Glutamate decarboxylase: Difference between revisions

Jump to navigation Jump to search
VisualWikitext
m (Robot: Automated text replacement (-{{SIB}} + & -{{EH}} + & -{{EJ}} + & -{{Editor Help}} + & -{{Editor Join}} +))
imported>JCW-CleanerBot
m (task, replaced: PloS One → PLOS One)
 
(2 intermediate revisions by 2 users not shown)
Line 1: Line 1:
{{protein
{{enzyme
| Name = glutamate decarboxylase
| EC_number = 4.1.1.15
| CAS_number = 9024-58-2m
| IUBMB_EC_number = 4/1/1/15
| GO_code = 0004351
| image =
| width =
| caption =
}}
{{infobox protein
| Name = [[GAD1|Glutamic acid decarboxylase 1]]
| Name = [[GAD1|Glutamic acid decarboxylase 1]]
| caption =  
| caption = GAD67 derived from {{PDB|2okj}}
| image =  
| image = PDB GAD67.jpg
| width =  
| width =  
| HGNCid = 4092
| HGNCid = 4092
| Symbol = [[GAD1]]
| Symbol = [[GAD1]]
| AltSymbols = GLUTAMATE DECARBOXYLASE, BRAIN, 67-KD; GAD67
| AltSymbols = glutamate decarboxylase 1<br />(brain, 67kD); GAD67
| EntrezGene = 2571
| EntrezGene = 2571
| OMIM = 605363
| OMIM = 605363
| RefSeq =
| RefSeq = NM_000817
| UniProt = Q99259
| UniProt = Q99259
| PDB =  
| PDB =  
Line 18: Line 28:
| LocusSupplementaryData =  
| LocusSupplementaryData =  
}}
}}
{{protein
{{infobox protein
| Name = [[GAD2|glutamic acid decarboxylase 2]]
| Name = [[GAD2|glutamic acid decarboxylase 2]]
| caption =  
| caption =  
Line 25: Line 35:
| HGNCid = 11284
| HGNCid = 11284
| Symbol = [[GAD2]]
| Symbol = [[GAD2]]
| AltSymbols =  
| AltSymbols = GAD65
| EntrezGene = 2572
| EntrezGene = 2572
| OMIM = 4093
| OMIM = 4093
| RefSeq =
| RefSeq = NM_001047
| UniProt = Q05329
| UniProt = Q05329
| PDB = 1ES0
| PDB =
| ECnumber = 4.1.1.15
| ECnumber = 4.1.1.15
| Chromosome = 10
| Chromosome = 10
Line 37: Line 47:
| LocusSupplementaryData =  
| LocusSupplementaryData =  
}}
}}
'''Glutamate decarboxylase''' or '''glutamic acid decarboxylase''' ('''GAD''') is an [[enzyme]] that catalyzes the decarboxylation of [[glutamate]] to [[GABA]] and CO<sub >2</sub>. GAD uses [[Pyridoxal-phosphate|PLP]] as a [[cofactor (biochemistry)|cofactor]]. The reaction proceeds as follows:
: HOOC-CH<sub >2</sub>-CH<sub >2</sub>-CH(NH<sub >2</sub>)-COOH → CO<sub >2</sub> + HOOC-CH<sub >2</sub>-CH<sub >2</sub>-CH<sub >2</sub>NH<sub >2</sub>
In mammals, GAD exists in two [[isoform]]s with molecular weights of 67 and 65 kDa (GAD<sub>67</sub> and GAD<sub>65</sub>), which are encoded by two different [[gene]]s on different [[chromosome]]s ([[GAD1]] and [[GAD2]] genes, chromosomes 4 and 10 respectively).<ref name="pmid2069816">{{cite journal | vauthors = Erlander MG, Tillakaratne NJ, Feldblum S, Patel N, Tobin AJ | title = Two genes encode distinct glutamate decarboxylases | journal = Neuron | volume = 7 | issue = 1 | pages = 91–100 | date = July 1991 | pmid = 2069816 | doi = 10.1016/0896-6273(91)90077-D }}</ref><ref name="ReferenceA">{{cite journal | vauthors = Langendorf CG, Tuck KL, Key TL, Fenalti G, Pike RN, Rosado CJ, Wong AS, Buckle AM, Law RH, Whisstock JC | display-authors = 6 | title = Structural characterization of the mechanism through which human glutamic acid decarboxylase auto-activates | journal = Bioscience Reports | volume = 33 | issue = 1 | pages = 137–44 | date = January 2013 | pmid = 23126365 | pmc = 3546353 | doi = 10.1042/BSR20120111 }}</ref> GAD<sub>67</sub> and GAD<sub>65</sub> are expressed in the brain where GABA is used as a [[neurotransmitter]], and they are also expressed in the [[insulin]]-producing [[beta cell|β-cells]] of the [[pancreas]], in varying ratios depending upon the species.<ref name="pmid8243826">{{cite journal | vauthors = Kim J, Richter W, Aanstoot HJ, Shi Y, Fu Q, Rajotte R, Warnock G, Baekkeskov S | display-authors = 6 | title = Differential expression of GAD65 and GAD67 in human, rat, and mouse pancreatic islets | journal = Diabetes | volume = 42 | issue = 12 | pages = 1799–808 | date = December 1993 | pmid = 8243826 | doi = 10.2337/diab.42.12.1799 }}</ref> Together, these two enzymes maintain the only physiological supply of GABA in mammals.<ref name="ReferenceA"/>
Several truncated transcripts and polypeptides of GAD<sub>67</sub> are detectable in the developing brain,<ref name="pmid7935469">{{cite journal | vauthors = Szabo G, Katarova Z, Greenspan R | title = Distinct protein forms are produced from alternatively spliced bicistronic glutamic acid decarboxylase mRNAs during development | journal = Molecular and Cellular Biology | volume = 14 | issue = 11 | pages = 7535–45 | date = November 1994 | pmid = 7935469 | pmc = 359290 | doi = 10.1128/mcb.14.11.7535 }}</ref> however their function, if any, is unknown.
==Regulation of GAD65 and GAD67==
Despite an extensive sequence similarity between the two genes, GAD65 and GAD67 fulfill very different roles within the human body. Additionally, research suggests that Gad65 and Gad67 are regulated by distinctly different cellular mechanisms.
GAD<sub>65</sub> and GAD<sub>67</sub> synthesize GABA at different locations in the cell, at different developmental times, and for functionally different purposes.<ref name="pmid9777629">{{cite journal | vauthors = Pinal CS, Tobin AJ | title = Uniqueness and redundancy in GABA production | journal = Perspectives on Developmental Neurobiology | volume = 5 | issue = 2-3 | pages = 109–18 | year = 1998 | pmid = 9777629 }}</ref><ref name="Soghomonian_1998">{{cite journal | vauthors = Soghomonian JJ, Martin DL | title = Two isoforms of glutamate decarboxylase: why? | journal = Trends in Pharmacological Sciences | volume = 19 | issue = 12 | pages = 500–5 | date = December 1998 | pmid = 9871412 | doi = 10.1016/s0165-6147(98)01270-x }}</ref> GAD<sub>67</sub> is spread evenly throughout the cell while GAD<sub>65</sub> is localized to nerve terminals.<ref name="pmid9777629" /><ref name="pmid1988566">{{cite journal | vauthors = Kaufman DL, Houser CR, Tobin AJ | title = Two forms of the gamma-aminobutyric acid synthetic enzyme glutamate decarboxylase have distinct intraneuronal distributions and cofactor interactions | journal = Journal of Neurochemistry | volume = 56 | issue = 2 | pages = 720–3 | date = February 1991 | pmid = 1988566 | doi = 10.1111/j.1471-4159.1991.tb08211.x }}</ref><ref name="pmid25647668">{{cite journal | vauthors = Kanaani J, Cianciaruso C, Phelps EA, Pasquier M, Brioudes E, Billestrup N, Baekkeskov S | title = Compartmentalization of GABA synthesis by GAD67 differs between pancreatic beta cells and neurons | journal = PLOS One | volume = 10 | issue = 2 | pages = e0117130 | year = 2015 | pmid = 25647668 | pmc = 4315522 | doi = 10.1371/journal.pone.0117130 }}</ref>  GAD<sub>67</sub> synthesizes GABA for neuron activity unrelated to neurotransmission, such as synaptogenesis and protection from neural injury.<ref name="pmid9777629" /><ref name="Soghomonian_1998" /> This function requires widespread, ubiquitous presence of GABA. GAD<sub>65</sub>, however, synthesizes GABA for neurotransmission,<ref name="pmid9777629" /> and therefore is only necessary at nerve terminals and synapses. In order to aid in neurotransmission, GAD<sub>65</sub> forms a complex with Heat Shock Cognate 70 (HSC<sub>70</sub>), cysteine string protein (CSP) and Vesicular GABA transporter VGAT, which, as a complex, helps package GABA into vesicles for release during neurotransmission.<ref>{{cite journal | vauthors = Jin H, Wu H, Osterhaus G, Wei J, Davis K, Sha D, Floor E, Hsu CC, Kopke RD, Wu JY | display-authors = 6 | title = Demonstration of functional coupling between gamma -aminobutyric acid (GABA) synthesis and vesicular GABA transport into synaptic vesicles | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 100 | issue = 7 | pages = 4293–8 | date = April 2003 | pmid = 12634427 | pmc = 153086 | doi = 10.1073/pnas.0730698100 }}</ref> GAD<sub>67</sub> is transcribed during early development, while GAD<sub>65</sub> is not transcribed until later in life.<ref name="pmid9777629" /> This developmental difference in GAD<sub>67</sub> and GAD<sub>65</sub> reflects the functional properties of each isoform; GAD<sub>67</sub> is needed throughout development for normal cellular functioning, while GAD<sub>65</sub> is not needed until slightly later in development when synaptic inhibition is more prevalent.<ref name="pmid9777629" />
[[File:MouseGad65ThGad67.jpg|thumb|Gad65 in red, Gad67 in green, and Tyrosine Hydroxylase (blue) in the Ventral Tegmental Area of the mouse brain.]]
GAD<sub>67</sub> and GAD<sub>65</sub> are also regulated differently post-translationally. Both GAD<sub>65</sub> and GAD<sub>67</sub> are regulated via phosphorylation of a dynamic catalytic loop,<ref>{{cite journal | vauthors = Wei J, Davis KM, Wu H, Wu JY | title = Protein phosphorylation of human brain glutamic acid decarboxylase (GAD)65 and GAD67 and its physiological implications | journal = Biochemistry | volume = 43 | issue = 20 | pages = 6182–9 | date = May 2004 | pmid = 15147202 | pmc =  | doi = 10.1021/bi0496992 }}</ref><ref>{{cite journal | vauthors = Fenalti G, Law RH, Buckle AM, Langendorf C, Tuck K, Rosado CJ, Faux NG, Mahmood K, Hampe CS, Banga JP, Wilce M, Schmidberger J, Rossjohn J, El-Kabbani O, Pike RN, Smith AI, Mackay IR, Rowley MJ, Whisstock JC | display-authors = 6 | title = GABA production by glutamic acid decarboxylase is regulated by a dynamic catalytic loop | journal = Nature Structural & Molecular Biology | volume = 14 | issue = 4 | pages = 280–6 | date = April 2007 | pmid = 17384644 | doi = 10.1038/nsmb1228 }}</ref> but the regulation of these isoforms differs; GAD<sub>65</sub> is activated by phosphorylation while GAD<sub>67</sub> is inhibited by phosphorylation. GAD67 is predominantly found activated (~92%), whereas GAD65 is predominantly found inactivated (~72%).<ref name="pmid12887686"/> GAD<sub>67</sub> is phosphorylated at threonine 91 by protein kinase A (PKA), while GAD<sub>65</sub> is phosphorylated, and therefore regulated by, protein kinase C (PKC). Both GAD<sub>67</sub> and GAD<sub>65</sub> are also regulated post-translationally by [[Pyridoxal phosphate|Pyridoxal 5’-phosphate]] (PLP); GAD is activated when bound to PLP and inactive when not bound to PLP.<ref name="pmid12887686">{{cite journal | vauthors = Battaglioli G, Liu H, Martin DL | title = Kinetic differences between the isoforms of glutamate decarboxylase: implications for the regulation of GABA synthesis | journal = Journal of Neurochemistry | volume = 86 | issue = 4 | pages = 879–87 | date = August 2003 | pmid = 12887686 | doi = 10.1046/j.1471-4159.2003.01910.x }}</ref> Majority of GAD<sub>67</sub> is bound to PLP at any given time, whereas GAD<sub>65</sub> binds PLP when GABA is needed for neurotransmission.<ref name="pmid12887686" /> This reflects the functional properties of the two isoforms; GAD<sub>67</sub> must be active at all times for normal cellular functioning, and is therefore constantly activated by PLP, while GAD<sub>65</sub> must only be activated when GABA neurotransmission occurs, and is therefore regulated according to the synaptic environment.
Studies with mice also show functional differences between Gad67 and Gad65. GAD67−/− mice are born with cleft palate and die within a day after birth while GAD65−/− mice survive with a slightly increased tendency in seizures. Additionally, GAD65+/- have symptoms defined similarly to ADHD in humans.<ref>{{Cite journal | vauthors = Ueno H | title = Enzymatic and structural aspects on glutamate decarboxylase. | journal = Journal of Molecular Catalysis B: Enzymatic. | date = October 2000 | volume = 10 | issue = 1–3 | pages = 67–79 | doi = 10.1016/S1381-1177(00)00114-4 }}</ref>
== Role in the Nervous System ==
Both GAD67 and GAD65 are present in all types of synapses within the human nervous system. This includes dendrodendritic, axosomatic, and axodendritic synapses. Preliminary evidence suggests that GAD65 is dominant in the visual and neuroendocrine systems, which undergo more phasic changes. It is also believed that GAD67 is present at higher amounts in tonically active neurons.<ref>{{cite journal | vauthors = Feldblum S, Erlander MG, Tobin AJ | title = Different distributions of GAD65 and GAD67 mRNAs suggest that the two glutamate decarboxylases play distinctive functional roles | journal = Journal of Neuroscience Research | volume = 34 | issue = 6 | pages = 689–706 | date = April 1993 | pmid = 8315667 | doi = 10.1002/jnr.490340612 }}</ref>
== Role in pathology ==
=== Autism ===
Both GAD65 and GAD67 experience significant downregulation in cases of autism. In a comparison of autistic versus control brains, GAD65 and GAD67 experienced a downregulation average of 50% in parietal and cerebellar cortices of autistic brains.<ref name = "Fatemi_2002">{{cite journal | vauthors = Fatemi SH, Halt AR, Stary JM, Kanodia R, Schulz SC, Realmuto GR | title = Glutamic acid decarboxylase 65 and 67 kDa proteins are reduced in autistic parietal and cerebellar cortices | language = English | journal = Biological Psychiatry | volume = 52 | issue = 8 | pages = 805–10 | date = October 2002 | pmid = 12372652 | doi = 10.1016/S0006-3223(02)01430-0 }}</ref> Cerebellar purjinke cells also reported a 40% downregulation, suggesting that affected cerebellar nuclei may disrupt output to higher order motor and cognitive areas of the brain.<ref name="Soghomonian_1998" />
=== Diabetes ===
Both GAD<sub>67</sub> and GAD<sub>65</sub> are targets of [[autoantibody|autoantibodies]] in people who later develop type 1 [[diabetes mellitus]] or [[latent autoimmune diabetes]].<ref name="pmid1697648">{{cite journal | vauthors = Baekkeskov S, Aanstoot HJ, Christgau S, Reetz A, Solimena M, Cascalho M, Folli F, Richter-Olesen H, De Camilli P, Camilli PD | title = Identification of the 64K autoantigen in insulin-dependent diabetes as the GABA-synthesizing enzyme glutamic acid decarboxylase | journal = Nature | volume = 347 | issue = 6289 | pages = 151–6 | date = September 1990 | pmid = 1697648 | doi = 10.1038/347151a0 }}</ref><ref name="pmid1370298">{{cite journal | vauthors = Kaufman DL, Erlander MG, Clare-Salzler M, Atkinson MA, Maclaren NK, Tobin AJ | title = Autoimmunity to two forms of glutamate decarboxylase in insulin-dependent diabetes mellitus | journal = The Journal of Clinical Investigation | volume = 89 | issue = 1 | pages = 283–92 | date = January 1992 | pmid = 1370298 | pmc = 442846 | doi = 10.1172/JCI115573 }}</ref> Injections with GAD<sub>65</sub> in ways that induce immune tolerance have been shown to prevent type 1 diabetes in rodent models.<ref name="pmid8232539">{{cite journal | vauthors = Tisch R, Yang XD, Singer SM, Liblau RS, Fugger L, McDevitt HO | title = Immune response to glutamic acid decarboxylase correlates with insulitis in non-obese diabetic mice | journal = Nature | volume = 366 | issue = 6450 | pages = 72–5 | date = November 1993 | pmid = 8232539 | doi = 10.1038/366072a0 }}</ref><ref name="pmid7694152">{{cite journal | vauthors = Kaufman DL, Clare-Salzler M, Tian J, Forsthuber T, Ting GS, Robinson P, Atkinson MA, Sercarz EE, Tobin AJ, Lehmann PV | title = Spontaneous loss of T-cell tolerance to glutamic acid decarboxylase in murine insulin-dependent diabetes | journal = Nature | volume = 366 | issue = 6450 | pages = 69–72 | date = November 1993 | pmid = 7694152 | doi = 10.1038/366069a0 }}</ref><ref name="pmid8946834">{{cite journal | vauthors = Tian J, Clare-Salzler M, Herschenfeld A, Middleton B, Newman D, Mueller R, Arita S, Evans C, Atkinson MA, Mullen Y, Sarvetnick N, Tobin AJ, Lehmann PV, Kaufman DL | title = Modulating autoimmune responses to GAD inhibits disease progression and prolongs islet graft survival in diabetes-prone mice | journal = Nature Medicine | volume = 2 | issue = 12 | pages = 1348–53 | date = December 1996 | pmid = 8946834 | doi = 10.1038/nm1296-1348 }}</ref> In clinical trials, injections with GAD<sub>65</sub> have been shown to preserve some insulin production for 30 months in humans with type 1 diabetes.<ref name="pmid18843118">{{cite journal | vauthors = Ludvigsson J, Faresjö M, Hjorth M, Axelsson S, Chéramy M, Pihl M, Vaarala O, Forsander G, Ivarsson S, Johansson C, Lindh A, Nilsson NO, Aman J, Ortqvist E, Zerhouni P, Casas R | title = GAD treatment and insulin secretion in recent-onset type 1 diabetes | journal = The New England Journal of Medicine | volume = 359 | issue = 18 | pages = 1909–20 | date = October 2008 | pmid = 18843118 | doi = 10.1056/NEJMoa0804328 }}</ref><ref name="url_Diamyd">{{cite web | url = http://www.diamyd.com/docs/pressClip.aspx?section=investor&ClipID=420 | title = Diamyd announces completion of type 1 diabetes vaccine trial with long term efficacy demonstrated at 30 months | author = | date = 2008-01-28 | work = Press Release | publisher = Diamyd Medical AB | pages = | access-date = 2010-01-13 }}</ref>
===Stiff person syndrome===
[[File:Stiff man human cerebellum.JPG|thumb|Stiff man human cerebellum stained with a reference anti-GAD65 monoclonal antibody. Thin arrows show presynaptic terminals staining only with the anti-GAD65 monoclonal antibody]]
High [[titer]]s of autoantibodies to glutamic acid decarboxylase (GAD) are well documented in association with [[stiff person syndrome]] (SPS).<ref>{{cite journal | vauthors = Dalakas MC, Fujii M, Li M, Lutfi B, Kyhos J, McElroy B | title = High-dose intravenous immune globulin for stiff-person syndrome | journal = The New England Journal of Medicine | volume = 345 | issue = 26 | pages = 1870–6 | date = December 2001 | pmid = 11756577 | doi = 10.1056/NEJMoa01167 }}</ref> Glutamic acid decarboxylase is the rate-limiting enzyme in the synthesis of γ-aminobutyric acid (GABA), and impaired function of GABAergic neurons has been implicated in the pathogenesis of SPS. Autoantibodies to GAD might be the causative agent or a disease marker.<ref>{{cite journal | vauthors = Chang T, Alexopoulos H, McMenamin M, Carvajal-González A, Alexander SK, Deacon R, Erdelyi F, Szabó G, Gabor S, Lang B, Blaes F, Brown P, Vincent A | title = Neuronal surface and glutamic acid decarboxylase autoantibodies in Nonparaneoplastic stiff person syndrome | journal = JAMA Neurology | volume = 70 | issue = 9 | pages = 1140–9 | date = September 2013 | pmid = 23877118 | doi = 10.1001/jamaneurol.2013.3499 }}</ref>
=== Schizophrenia and bipolar disorder ===
Substantial dysregulation of GAD mRNA expression, coupled with downregulation of [[reelin]], is observed in [[schizophrenia]] and [[bipolar disorder]].<ref name="pmid15237077">{{cite journal | vauthors = Woo TU, Walsh JP, Benes FM | title = Density of glutamic acid decarboxylase 67 messenger RNA-containing neurons that express the N-methyl-D-aspartate receptor subunit NR2A in the anterior cingulate cortex in schizophrenia and bipolar disorder | journal = Archives of General Psychiatry | volume = 61 | issue = 7 | pages = 649–57 | date = July 2004 | pmid = 15237077 | doi = 10.1001/archpsyc.61.7.649 }}</ref> The most pronounced downregulation of GAD<sub>67</sub> was found in hippocampal [[stratum oriens]] layer in both disorders and in other layers and structures of hippocampus with varying degrees.<ref name="pmid17553960">{{cite journal | vauthors = Benes FM, Lim B, Matzilevich D, Walsh JP, Subburaju S, Minns M | title = Regulation of the GABA cell phenotype in hippocampus of schizophrenics and bipolars | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 104 | issue = 24 | pages = 10164–9 | date = June 2007 | pmid = 17553960 | pmc = 1888575 | doi = 10.1073/pnas.0703806104 }}</ref>


{{SI}}
GAD<sub>67</sub> is a key enzyme involved in the synthesis of inhibitory neurotransmitter [[GABA]] and people with schizophrenia have been shown to express lower amounts of GAD<sub>67</sub> in the dorsolateral prefrontal cortex compared to healthy controls.<ref name="pmid24874453">{{cite journal | vauthors = Kimoto S, Bazmi HH, Lewis DA | title = Lower expression of glutamic acid decarboxylase 67 in the prefrontal cortex in schizophrenia: contribution of altered regulation by Zif268 | journal = The American Journal of Psychiatry | volume = 171 | issue = 9 | pages = 969–78 | date = September 2014 | pmid = 24874453 | pmc = 4376371 | doi = 10.1176/appi.ajp.2014.14010004 }}</ref>  The mechanism underlying the decreased levels of GAD<sub>67</sub> in people with schizophrenia remains unclear.  Some have proposed that an immediate early gene, Zif268, which normally binds to the [[promoter (genetics)|promoter]] region of GAD<sub>67</sub> and increases transcription of GAD<sub>67</sub>, is lower in schizophrenic patients, thus contributing to decreased levels of GAD<sub>67</sub>.<ref name="pmid24874453"/>  Since the dorsolateral prefrontal cortex (DLPFC) is involved in working memory, and GAD<sub>67</sub> and Zif268 mRNA levels are lower in the DLPFC of schizophrenic patients, this molecular alteration may account, at least in part, for the working memory impairments associated with the disease.


=== Parkinson disease ===


==Overview==
The bilateral delivery of [[glutamic acid decarboxylase]] (GAD) by an [[adeno-associated viral vector]] into the subthalamic nucleus of patients between 30 and 75 years of age with advanced, progressive, levodopa-responsive [[Parkinson disease]] resulted in significant improvement over baseline during the course of a six-month study.<ref name="pmid21419704">{{cite journal | vauthors = LeWitt PA, Rezai AR, Leehey MA, Ojemann SG, Flaherty AW, Eskandar EN, Kostyk SK, Thomas K, Sarkar A, Siddiqui MS, Tatter SB, Schwalb JM, Poston KL, Henderson JM, Kurlan RM, Richard IH, Van Meter L, Sapan CV, During MJ, Kaplitt MG, Feigin A | title = AAV2-GAD gene therapy for advanced Parkinson's disease: a double-blind, sham-surgery controlled, randomised trial | journal = The Lancet. Neurology | volume = 10 | issue = 4 | pages = 309–19 | date = April 2011 | pmid = 21419704 | doi = 10.1016/S1474-4422(11)70039-4 }}</ref>
'''Glutamate decarboxylase''' (GAD) is an [[enzyme]] that catalyzes the decarboxylation of [[glutamate]] to [[GABA]] and CO<sub >2</sub >. GAD uses [[Pyridoxal-phosphate|PLP]] as a [[cofactor]]. The reaction proceeds as follows:


HOOC-CH<sub >2</sub >-CH<sub >2</sub >-CH(NH<sub >2</sub >)-COOH → CO<sub >2</sub > + HOOC-CH<sub >2</sub >-CH<sub >2</sub >-CH<sub >2</sub >NH<sub >2</sub >
=== Cerebellar disorders ===


In mammals, GAD exists in two [[isoform]]s encoded by two different [[gene]]s - ''Gad1'' and ''Gad2''. These isoforms are GAD<sub>67</sub> and GAD<sub>65</sub> with molecular weights of 67 and 65 [[kDa]], respectively.<ref name="pmid2069816">{{cite journal | author = Erlander MG, Tillakaratne NJ, Feldblum S, Patel N, Tobin AJ | title = Two genes encode distinct glutamate decarboxylases | journal = Neuron | volume = 7 | issue = 1 | pages = 91–100 | year = 1991 | pmid = 2069816 | doi = 10.1016/0896-6273(91)90077-D | issn = }}</ref> GAD1 and GAD2 are expressed in the brain where GABA is used as a [[neurotransmitter]], GAD2 is also expressed in the pancreas.  
Intracerebellar administration of GAD autoantibodies to animals increases the excitability of motoneurons and impairs the production of [[Biological functions of nitric oxide|nitric oxide]] (NO), a molecule involved in learning. Epitope recognition contributes to cerebellar involvement.<ref>{{cite journal | vauthors = Manto MU, Hampe CS, Rogemond V, Honnorat J | title = Respective implications of glutamate decarboxylase antibodies in stiff person syndrome and cerebellar ataxia | journal = Orphanet Journal of Rare Diseases | volume = 6 | issue = 3 | pages = 3 | date = February 2011 | pmid = 21294897 | pmc = 3042903 | doi = 10.1186/1750-1172-6-3 }}</ref> Reduced GABA levels increase glutamate levels as a consequence of lower inhibition of  subtypes of GABA receptors. Higher glutamate levels activate microglia and activation of xc(−) increases the extracellular glutamate release.<ref>{{cite journal | vauthors = Mitoma H, Manto M, Hampe CS | title = Pathogenic Roles of Glutamic Acid Decarboxylase 65 Autoantibodies in Cerebellar Ataxias | journal = Journal of Immunology Research | volume = 2017 | pages = 2913297 | date = 2017-03-12 | pmid = 28386570 | doi = 10.1155/2017/2913297 }}</ref>


==Role in pathology==
=== Neuropathic pain ===


===Diabetes===
[[Peripheral nerve injury]] of the sciatic nerve (a [[neuropathic pain]] model) induces a transient loss of GAD<sub>65</sub> immunoreactive terminals in the [[spinal cord]] [[posterior horn of spinal cord|dorsal horn]] and suggests a potential involvement for these alterations in the development and amelioration of pain behaviour.<ref name="pmid 25189404">{{cite journal | vauthors = Lorenzo LE, Magnussen C, Bailey AL, St Louis M, De Koninck Y, Ribeiro-da-Silva A | title = Spatial and temporal pattern of changes in the number of GAD65-immunoreactive inhibitory terminals in the rat superficial dorsal horn following peripheral nerve injury | journal = Molecular Pain | volume = 10 | issue = 1 | pages = 57 | date = September 2014 | pmid = 25189404 | pmc = 4164746 | doi = 10.1186/1744-8069-10-57 }}</ref>
Both GAD<sub>67</sub> and GAD<sub>65</sub> are targets of autoantibodies in people who later develop insulin-dependent [[diabetes mellitus]].<ref name="pmid1697648">{{cite journal | author = Baekkeskov S, Aanstoot HJ, Christgau S, Reetz A, Solimena M, Cascalho M, Folli F, Richter-Olesen H, De Camilli P, Camilli PD | title = Identification of the 64K autoantigen in insulin-dependent diabetes as the GABA-synthesizing enzyme glutamic acid decarboxylase | journal = Nature | volume = 347 | issue = 6289 | pages = 151–6 | year = 1990 | pmid = 1697648 | doi = 10.1038/347151a0 | issn = }}</ref> <ref name="pmid1370298">{{cite journal | author = Kaufman DL, Erlander MG, Clare-Salzler M, Atkinson MA, Maclaren NK, Tobin AJ | title = Autoimmunity to two forms of glutamate decarboxylase in insulin-dependent diabetes mellitus | journal = J. Clin. Invest. | volume = 89 | issue = 1 | pages = 283–92 | year = 1992 | pmid = 1370298 | doi = | issn = | url = http://www.pubmedcentral.gov/articlerender.fcgi?tool=pubmed&pubmedid=1370298}}</ref> Injections with GAD<sub>65</sub> has been shown to preserve some insulin production for 30 months in humans with type 1 diabetes.<ref>[http://www.diamyd.se/docs/PressClip.aspx?PageID=4&LangID=2&ClipID=420&sm=b_b Diamyd press release]</ref>


===Schizophrenia and Bipolar disorder===
==Other Anti-GAD-associated neurologic disorders==
Substantial dysregulation of GAD mRNA expression, coupled with downregulation of [[reelin]], is observed in [[schizophrenia]] and [[bipolar disorder]].<ref name="pmid15237077">{{cite journal | author = Woo TU, Walsh JP, Benes FM | title = Density of glutamic acid decarboxylase 67 messenger RNA-containing neurons that express the N-methyl-D-aspartate receptor subunit NR2A in the anterior cingulate cortex in schizophrenia and bipolar disorder | journal = Arch. Gen. Psychiatry | volume = 61 | issue = 7 | pages = 649–57 | year = 2004 | pmid = 15237077 | doi = 10.1001/archpsyc.61.7.649 | issn = }}</ref> The most pronounced downregulation of GAD67 was found in hippocampal [[stratum oriens]] layer in both disorders and in other layers and structures of hippocampus with varying degrees.<ref name="pmid17553960">{{cite journal | author = Benes FM, Lim B, Matzilevich D, Walsh JP, Subburaju S, Minns M | title = Regulation of the GABA cell phenotype in hippocampus of schizophrenics and bipolars | journal = Proc. Natl. Acad. Sci. U.S.A. | volume = 104 | issue = 24 | pages = 10164–9 | year = 2007 | pmid = 17553960 | doi = 10.1073/pnas.0703806104 | issn = }}</ref>
 
Antibodies directed against glutamic acid decarboxylase (GAD) are increasingly found in patients with other symptoms indicative of central nervous system (CNS) dysfunction, such as [[ataxia]], progressive encephalomyelitis with rigidity and myoclonus [[(PERM)]], [[limbic encephalitis]], and [[epilepsy]].<ref>{{cite journal | vauthors = Dayalu P, Teener JW | title = Stiff Person syndrome and other anti-GAD-associated neurologic disorders | journal = Seminars in Neurology | volume = 32 | issue = 5 | pages = 544–9 | date = November 2012 | pmid = 23677666 | doi = 10.1055/s-0033-1334477 }}</ref> The pattern of anti-GAD antibodies in epilepsy differs from type 1 diabetes and stiff-person syndrome.<ref>{{cite journal | vauthors = Liimatainen S, Honnorat J, Pittock SJ, McKeon A, Manto M, Radtke JR, Hampe CS | title = GAD65 autoantibody characteristics in patients with co-occurring type 1 diabetes and epilepsy may help identify underlying epilepsy etiologies | journal = Orphanet Journal of Rare Diseases | volume = 13 | issue = 1 | pages = 55 | date = April 2018 | pmid = 29636076 | pmc = 5892043 | doi = 10.1186/s13023-018-0787-5 }}</ref>
 
== Role of glutamate decarboxylase in Citrus ==
It is also believed that the control of glutamate decarboxylase has the prospect of improving citrus produce quality post-harvest. In Citrus plants, research has shown that glutamate decarboxylase plays a key role in citrate metabolism. With the increase of glutamate decarboxylase via direct exposure, citrate levels have been seen to significantly increase within plants, and in conjunction post-harvest quality maintenance was significantly improved, and rot rates decreased.<ref>{{cite journal | vauthors = Sheng L, Shen D, Luo Y, Sun X, Wang J, Luo T, Zeng Y, Xu J, Deng X, Cheng Y | title = Exogenous γ-aminobutyric acid treatment affects citrate and amino acid accumulation to improve fruit quality and storage performance of postharvest citrus fruit | journal = Food Chemistry | volume = 216 | pages = 138–45 | date = February 2017 | pmid = 27596402 | doi = 10.1016/j.foodchem.2016.08.024 }}</ref>


== References ==
== References ==
{{Reflist|2}}
{{reflist|33em}}


== External links ==
== External links ==
* [http://www.schizophreniaforum.org/new/detail.asp?id=1358 Genetics, Expression Profiling Support GABA Deficits in Schizophrenia] - Schizophrenia Research Forum, 25 June 2007.
* {{commons-inline|Category:Glutamate decarboxylase|Glutamate decarboxylase}}
* [https://web.archive.org/web/20070815162255/http://www.schizophreniaforum.org/new/detail.asp?id=1358 Genetics, Expression Profiling Support GABA Deficits in Schizophrenia] - Schizophrenia Research Forum, 25 June 2007.
 
{{Neurotransmitter metabolism enzymes}}
{{Carbon-carbon lyases}}
{{Enzymes}}
{{GABA metabolism and transport modulators}}
{{Glutamate metabolism and transport modulators}}
{{Portal bar|Molecular and Cellular Biology|border=no}}


[[Category:EC 4.1.1]]
[[Category:EC 4.1.1]]
[[Category:Molecular neuroscience]]
[[Category:Molecular neuroscience]]
 
[[Category:Biology of bipolar disorder]]
{{Carbon-carbon lyases}}
[[Category:GABA]]
{{Amino acid metabolism enzymes}}
[[Category:Glutamate (neurotransmitter)]]
 
 
[[ru:Глутаматдекарбоксилаза]]
{{WH}}
{{WS}}

Latest revision as of 18:27, 5 January 2019

glutamate decarboxylase
Identifiers
EC number4.1.1.15
CAS number9024-58-2m
Databases
IntEnzIntEnz view
BRENDABRENDA entry
ExPASyNiceZyme view
KEGGKEGG entry
MetaCycmetabolic pathway
PRIAMprofile
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO
Glutamic acid decarboxylase 1
File:PDB GAD67.jpg
GAD67 derived from PDB: 2okj​
Identifiers
SymbolGAD1
Alt. symbolsglutamate decarboxylase 1
(brain, 67kD); GAD67
Entrez2571
HUGO4092
OMIM605363
RefSeqNM_000817
UniProtQ99259
Other data
EC number4.1.1.15
LocusChr. 2 q31
glutamic acid decarboxylase 2
Identifiers
SymbolGAD2
Alt. symbolsGAD65
Entrez2572
HUGO11284
OMIM4093
RefSeqNM_001047
UniProtQ05329
Other data
EC number4.1.1.15
LocusChr. 10 p11.23

Glutamate decarboxylase or glutamic acid decarboxylase (GAD) is an enzyme that catalyzes the decarboxylation of glutamate to GABA and CO2. GAD uses PLP as a cofactor. The reaction proceeds as follows:

HOOC-CH2-CH2-CH(NH2)-COOH → CO2 + HOOC-CH2-CH2-CH2NH2

In mammals, GAD exists in two isoforms with molecular weights of 67 and 65 kDa (GAD67 and GAD65), which are encoded by two different genes on different chromosomes (GAD1 and GAD2 genes, chromosomes 4 and 10 respectively).[1][2] GAD67 and GAD65 are expressed in the brain where GABA is used as a neurotransmitter, and they are also expressed in the insulin-producing β-cells of the pancreas, in varying ratios depending upon the species.[3] Together, these two enzymes maintain the only physiological supply of GABA in mammals.[2]

Several truncated transcripts and polypeptides of GAD67 are detectable in the developing brain,[4] however their function, if any, is unknown.

Regulation of GAD65 and GAD67

Despite an extensive sequence similarity between the two genes, GAD65 and GAD67 fulfill very different roles within the human body. Additionally, research suggests that Gad65 and Gad67 are regulated by distinctly different cellular mechanisms.

GAD65 and GAD67 synthesize GABA at different locations in the cell, at different developmental times, and for functionally different purposes.[5][6] GAD67 is spread evenly throughout the cell while GAD65 is localized to nerve terminals.[5][7][8] GAD67 synthesizes GABA for neuron activity unrelated to neurotransmission, such as synaptogenesis and protection from neural injury.[5][6] This function requires widespread, ubiquitous presence of GABA. GAD65, however, synthesizes GABA for neurotransmission,[5] and therefore is only necessary at nerve terminals and synapses. In order to aid in neurotransmission, GAD65 forms a complex with Heat Shock Cognate 70 (HSC70), cysteine string protein (CSP) and Vesicular GABA transporter VGAT, which, as a complex, helps package GABA into vesicles for release during neurotransmission.[9] GAD67 is transcribed during early development, while GAD65 is not transcribed until later in life.[5] This developmental difference in GAD67 and GAD65 reflects the functional properties of each isoform; GAD67 is needed throughout development for normal cellular functioning, while GAD65 is not needed until slightly later in development when synaptic inhibition is more prevalent.[5]

File:MouseGad65ThGad67.jpg
Gad65 in red, Gad67 in green, and Tyrosine Hydroxylase (blue) in the Ventral Tegmental Area of the mouse brain.

GAD67 and GAD65 are also regulated differently post-translationally. Both GAD65 and GAD67 are regulated via phosphorylation of a dynamic catalytic loop,[10][11] but the regulation of these isoforms differs; GAD65 is activated by phosphorylation while GAD67 is inhibited by phosphorylation. GAD67 is predominantly found activated (~92%), whereas GAD65 is predominantly found inactivated (~72%).[12] GAD67 is phosphorylated at threonine 91 by protein kinase A (PKA), while GAD65 is phosphorylated, and therefore regulated by, protein kinase C (PKC). Both GAD67 and GAD65 are also regulated post-translationally by Pyridoxal 5’-phosphate (PLP); GAD is activated when bound to PLP and inactive when not bound to PLP.[12] Majority of GAD67 is bound to PLP at any given time, whereas GAD65 binds PLP when GABA is needed for neurotransmission.[12] This reflects the functional properties of the two isoforms; GAD67 must be active at all times for normal cellular functioning, and is therefore constantly activated by PLP, while GAD65 must only be activated when GABA neurotransmission occurs, and is therefore regulated according to the synaptic environment.

Studies with mice also show functional differences between Gad67 and Gad65. GAD67−/− mice are born with cleft palate and die within a day after birth while GAD65−/− mice survive with a slightly increased tendency in seizures. Additionally, GAD65+/- have symptoms defined similarly to ADHD in humans.[13]

Role in the Nervous System

Both GAD67 and GAD65 are present in all types of synapses within the human nervous system. This includes dendrodendritic, axosomatic, and axodendritic synapses. Preliminary evidence suggests that GAD65 is dominant in the visual and neuroendocrine systems, which undergo more phasic changes. It is also believed that GAD67 is present at higher amounts in tonically active neurons.[14]

Role in pathology

Autism

Both GAD65 and GAD67 experience significant downregulation in cases of autism. In a comparison of autistic versus control brains, GAD65 and GAD67 experienced a downregulation average of 50% in parietal and cerebellar cortices of autistic brains.[15] Cerebellar purjinke cells also reported a 40% downregulation, suggesting that affected cerebellar nuclei may disrupt output to higher order motor and cognitive areas of the brain.[6]

Diabetes

Both GAD67 and GAD65 are targets of autoantibodies in people who later develop type 1 diabetes mellitus or latent autoimmune diabetes.[16][17] Injections with GAD65 in ways that induce immune tolerance have been shown to prevent type 1 diabetes in rodent models.[18][19][20] In clinical trials, injections with GAD65 have been shown to preserve some insulin production for 30 months in humans with type 1 diabetes.[21][22]

Stiff person syndrome

File:Stiff man human cerebellum.JPG
Stiff man human cerebellum stained with a reference anti-GAD65 monoclonal antibody. Thin arrows show presynaptic terminals staining only with the anti-GAD65 monoclonal antibody

High titers of autoantibodies to glutamic acid decarboxylase (GAD) are well documented in association with stiff person syndrome (SPS).[23] Glutamic acid decarboxylase is the rate-limiting enzyme in the synthesis of γ-aminobutyric acid (GABA), and impaired function of GABAergic neurons has been implicated in the pathogenesis of SPS. Autoantibodies to GAD might be the causative agent or a disease marker.[24]

Schizophrenia and bipolar disorder

Substantial dysregulation of GAD mRNA expression, coupled with downregulation of reelin, is observed in schizophrenia and bipolar disorder.[25] The most pronounced downregulation of GAD67 was found in hippocampal stratum oriens layer in both disorders and in other layers and structures of hippocampus with varying degrees.[26]

GAD67 is a key enzyme involved in the synthesis of inhibitory neurotransmitter GABA and people with schizophrenia have been shown to express lower amounts of GAD67 in the dorsolateral prefrontal cortex compared to healthy controls.[27] The mechanism underlying the decreased levels of GAD67 in people with schizophrenia remains unclear. Some have proposed that an immediate early gene, Zif268, which normally binds to the promoter region of GAD67 and increases transcription of GAD67, is lower in schizophrenic patients, thus contributing to decreased levels of GAD67.[27] Since the dorsolateral prefrontal cortex (DLPFC) is involved in working memory, and GAD67 and Zif268 mRNA levels are lower in the DLPFC of schizophrenic patients, this molecular alteration may account, at least in part, for the working memory impairments associated with the disease.

Parkinson disease

The bilateral delivery of glutamic acid decarboxylase (GAD) by an adeno-associated viral vector into the subthalamic nucleus of patients between 30 and 75 years of age with advanced, progressive, levodopa-responsive Parkinson disease resulted in significant improvement over baseline during the course of a six-month study.[28]

Cerebellar disorders

Intracerebellar administration of GAD autoantibodies to animals increases the excitability of motoneurons and impairs the production of nitric oxide (NO), a molecule involved in learning. Epitope recognition contributes to cerebellar involvement.[29] Reduced GABA levels increase glutamate levels as a consequence of lower inhibition of subtypes of GABA receptors. Higher glutamate levels activate microglia and activation of xc(−) increases the extracellular glutamate release.[30]

Neuropathic pain

Peripheral nerve injury of the sciatic nerve (a neuropathic pain model) induces a transient loss of GAD65 immunoreactive terminals in the spinal cord dorsal horn and suggests a potential involvement for these alterations in the development and amelioration of pain behaviour.[31]

Other Anti-GAD-associated neurologic disorders

Antibodies directed against glutamic acid decarboxylase (GAD) are increasingly found in patients with other symptoms indicative of central nervous system (CNS) dysfunction, such as ataxia, progressive encephalomyelitis with rigidity and myoclonus (PERM), limbic encephalitis, and epilepsy.[32] The pattern of anti-GAD antibodies in epilepsy differs from type 1 diabetes and stiff-person syndrome.[33]

Role of glutamate decarboxylase in Citrus

It is also believed that the control of glutamate decarboxylase has the prospect of improving citrus produce quality post-harvest. In Citrus plants, research has shown that glutamate decarboxylase plays a key role in citrate metabolism. With the increase of glutamate decarboxylase via direct exposure, citrate levels have been seen to significantly increase within plants, and in conjunction post-harvest quality maintenance was significantly improved, and rot rates decreased.[34]

References

  1. ↑ Erlander MG, Tillakaratne NJ, Feldblum S, Patel N, Tobin AJ (July 1991). "Two genes encode distinct glutamate decarboxylases". Neuron. 7 (1): 91–100. doi:10.1016/0896-6273(91)90077-D. PMID 2069816.
  2. ↑ 2.0 2.1 Langendorf CG, Tuck KL, Key TL, Fenalti G, Pike RN, Rosado CJ, et al. (January 2013). "Structural characterization of the mechanism through which human glutamic acid decarboxylase auto-activates". Bioscience Reports. 33 (1): 137–44. doi:10.1042/BSR20120111. PMC 3546353. PMID 23126365.
  3. ↑ Kim J, Richter W, Aanstoot HJ, Shi Y, Fu Q, Rajotte R, et al. (December 1993). "Differential expression of GAD65 and GAD67 in human, rat, and mouse pancreatic islets". Diabetes. 42 (12): 1799–808. doi:10.2337/diab.42.12.1799. PMID 8243826.
  4. ↑ Szabo G, Katarova Z, Greenspan R (November 1994). "Distinct protein forms are produced from alternatively spliced bicistronic glutamic acid decarboxylase mRNAs during development". Molecular and Cellular Biology. 14 (11): 7535–45. doi:10.1128/mcb.14.11.7535. PMC 359290. PMID 7935469.
  5. ↑ 5.0 5.1 5.2 5.3 5.4 5.5 Pinal CS, Tobin AJ (1998). "Uniqueness and redundancy in GABA production". Perspectives on Developmental Neurobiology. 5 (2–3): 109–18. PMID 9777629.
  6. ↑ 6.0 6.1 6.2 Soghomonian JJ, Martin DL (December 1998). "Two isoforms of glutamate decarboxylase: why?". Trends in Pharmacological Sciences. 19 (12): 500–5. doi:10.1016/s0165-6147(98)01270-x. PMID 9871412.
  7. ↑ Kaufman DL, Houser CR, Tobin AJ (February 1991). "Two forms of the gamma-aminobutyric acid synthetic enzyme glutamate decarboxylase have distinct intraneuronal distributions and cofactor interactions". Journal of Neurochemistry. 56 (2): 720–3. doi:10.1111/j.1471-4159.1991.tb08211.x. PMID 1988566.
  8. ↑ Kanaani J, Cianciaruso C, Phelps EA, Pasquier M, Brioudes E, Billestrup N, Baekkeskov S (2015). "Compartmentalization of GABA synthesis by GAD67 differs between pancreatic beta cells and neurons". PLOS One. 10 (2): e0117130. doi:10.1371/journal.pone.0117130. PMC 4315522. PMID 25647668.
  9. ↑ Jin H, Wu H, Osterhaus G, Wei J, Davis K, Sha D, et al. (April 2003). "Demonstration of functional coupling between gamma -aminobutyric acid (GABA) synthesis and vesicular GABA transport into synaptic vesicles". Proceedings of the National Academy of Sciences of the United States of America. 100 (7): 4293–8. doi:10.1073/pnas.0730698100. PMC 153086. PMID 12634427.
  10. ↑ Wei J, Davis KM, Wu H, Wu JY (May 2004). "Protein phosphorylation of human brain glutamic acid decarboxylase (GAD)65 and GAD67 and its physiological implications". Biochemistry. 43 (20): 6182–9. doi:10.1021/bi0496992. PMID 15147202.
  11. ↑ Fenalti G, Law RH, Buckle AM, Langendorf C, Tuck K, Rosado CJ, et al. (April 2007). "GABA production by glutamic acid decarboxylase is regulated by a dynamic catalytic loop". Nature Structural & Molecular Biology. 14 (4): 280–6. doi:10.1038/nsmb1228. PMID 17384644.
  12. ↑ 12.0 12.1 12.2 Battaglioli G, Liu H, Martin DL (August 2003). "Kinetic differences between the isoforms of glutamate decarboxylase: implications for the regulation of GABA synthesis". Journal of Neurochemistry. 86 (4): 879–87. doi:10.1046/j.1471-4159.2003.01910.x. PMID 12887686.
  13. ↑ Ueno H (October 2000). "Enzymatic and structural aspects on glutamate decarboxylase". Journal of Molecular Catalysis B: Enzymatic. 10 (1–3): 67–79. doi:10.1016/S1381-1177(00)00114-4.
  14. ↑ Feldblum S, Erlander MG, Tobin AJ (April 1993). "Different distributions of GAD65 and GAD67 mRNAs suggest that the two glutamate decarboxylases play distinctive functional roles". Journal of Neuroscience Research. 34 (6): 689–706. doi:10.1002/jnr.490340612. PMID 8315667.
  15. ↑ Fatemi SH, Halt AR, Stary JM, Kanodia R, Schulz SC, Realmuto GR (October 2002). "Glutamic acid decarboxylase 65 and 67 kDa proteins are reduced in autistic parietal and cerebellar cortices". Biological Psychiatry. 52 (8): 805–10. doi:10.1016/S0006-3223(02)01430-0. PMID 12372652.
  16. ↑ Baekkeskov S, Aanstoot HJ, Christgau S, Reetz A, Solimena M, Cascalho M, Folli F, Richter-Olesen H, De Camilli P, Camilli PD (September 1990). "Identification of the 64K autoantigen in insulin-dependent diabetes as the GABA-synthesizing enzyme glutamic acid decarboxylase". Nature. 347 (6289): 151–6. doi:10.1038/347151a0. PMID 1697648.
  17. ↑ Kaufman DL, Erlander MG, Clare-Salzler M, Atkinson MA, Maclaren NK, Tobin AJ (January 1992). "Autoimmunity to two forms of glutamate decarboxylase in insulin-dependent diabetes mellitus". The Journal of Clinical Investigation. 89 (1): 283–92. doi:10.1172/JCI115573. PMC 442846. PMID 1370298.
  18. ↑ Tisch R, Yang XD, Singer SM, Liblau RS, Fugger L, McDevitt HO (November 1993). "Immune response to glutamic acid decarboxylase correlates with insulitis in non-obese diabetic mice". Nature. 366 (6450): 72–5. doi:10.1038/366072a0. PMID 8232539.
  19. ↑ Kaufman DL, Clare-Salzler M, Tian J, Forsthuber T, Ting GS, Robinson P, Atkinson MA, Sercarz EE, Tobin AJ, Lehmann PV (November 1993). "Spontaneous loss of T-cell tolerance to glutamic acid decarboxylase in murine insulin-dependent diabetes". Nature. 366 (6450): 69–72. doi:10.1038/366069a0. PMID 7694152.
  20. ↑ Tian J, Clare-Salzler M, Herschenfeld A, Middleton B, Newman D, Mueller R, Arita S, Evans C, Atkinson MA, Mullen Y, Sarvetnick N, Tobin AJ, Lehmann PV, Kaufman DL (December 1996). "Modulating autoimmune responses to GAD inhibits disease progression and prolongs islet graft survival in diabetes-prone mice". Nature Medicine. 2 (12): 1348–53. doi:10.1038/nm1296-1348. PMID 8946834.
  21. ↑ Ludvigsson J, Faresjö M, Hjorth M, Axelsson S, Chéramy M, Pihl M, Vaarala O, Forsander G, Ivarsson S, Johansson C, Lindh A, Nilsson NO, Aman J, Ortqvist E, Zerhouni P, Casas R (October 2008). "GAD treatment and insulin secretion in recent-onset type 1 diabetes". The New England Journal of Medicine. 359 (18): 1909–20. doi:10.1056/NEJMoa0804328. PMID 18843118.
  22. ↑ "Diamyd announces completion of type 1 diabetes vaccine trial with long term efficacy demonstrated at 30 months". Press Release. Diamyd Medical AB. 2008-01-28. Retrieved 2010-01-13.
  23. ↑ Dalakas MC, Fujii M, Li M, Lutfi B, Kyhos J, McElroy B (December 2001). "High-dose intravenous immune globulin for stiff-person syndrome". The New England Journal of Medicine. 345 (26): 1870–6. doi:10.1056/NEJMoa01167. PMID 11756577.
  24. ↑ Chang T, Alexopoulos H, McMenamin M, Carvajal-González A, Alexander SK, Deacon R, Erdelyi F, Szabó G, Gabor S, Lang B, Blaes F, Brown P, Vincent A (September 2013). "Neuronal surface and glutamic acid decarboxylase autoantibodies in Nonparaneoplastic stiff person syndrome". JAMA Neurology. 70 (9): 1140–9. doi:10.1001/jamaneurol.2013.3499. PMID 23877118.
  25. ↑ Woo TU, Walsh JP, Benes FM (July 2004). "Density of glutamic acid decarboxylase 67 messenger RNA-containing neurons that express the N-methyl-D-aspartate receptor subunit NR2A in the anterior cingulate cortex in schizophrenia and bipolar disorder". Archives of General Psychiatry. 61 (7): 649–57. doi:10.1001/archpsyc.61.7.649. PMID 15237077.
  26. ↑ Benes FM, Lim B, Matzilevich D, Walsh JP, Subburaju S, Minns M (June 2007). "Regulation of the GABA cell phenotype in hippocampus of schizophrenics and bipolars". Proceedings of the National Academy of Sciences of the United States of America. 104 (24): 10164–9. doi:10.1073/pnas.0703806104. PMC 1888575. PMID 17553960.
  27. ↑ 27.0 27.1 Kimoto S, Bazmi HH, Lewis DA (September 2014). "Lower expression of glutamic acid decarboxylase 67 in the prefrontal cortex in schizophrenia: contribution of altered regulation by Zif268". The American Journal of Psychiatry. 171 (9): 969–78. doi:10.1176/appi.ajp.2014.14010004. PMC 4376371. PMID 24874453.
  28. ↑ LeWitt PA, Rezai AR, Leehey MA, Ojemann SG, Flaherty AW, Eskandar EN, Kostyk SK, Thomas K, Sarkar A, Siddiqui MS, Tatter SB, Schwalb JM, Poston KL, Henderson JM, Kurlan RM, Richard IH, Van Meter L, Sapan CV, During MJ, Kaplitt MG, Feigin A (April 2011). "AAV2-GAD gene therapy for advanced Parkinson's disease: a double-blind, sham-surgery controlled, randomised trial". The Lancet. Neurology. 10 (4): 309–19. doi:10.1016/S1474-4422(11)70039-4. PMID 21419704.
  29. ↑ Manto MU, Hampe CS, Rogemond V, Honnorat J (February 2011). "Respective implications of glutamate decarboxylase antibodies in stiff person syndrome and cerebellar ataxia". Orphanet Journal of Rare Diseases. 6 (3): 3. doi:10.1186/1750-1172-6-3. PMC 3042903. PMID 21294897.
  30. ↑ Mitoma H, Manto M, Hampe CS (2017-03-12). "Pathogenic Roles of Glutamic Acid Decarboxylase 65 Autoantibodies in Cerebellar Ataxias". Journal of Immunology Research. 2017: 2913297. doi:10.1155/2017/2913297. PMID 28386570.
  31. ↑ Lorenzo LE, Magnussen C, Bailey AL, St Louis M, De Koninck Y, Ribeiro-da-Silva A (September 2014). "Spatial and temporal pattern of changes in the number of GAD65-immunoreactive inhibitory terminals in the rat superficial dorsal horn following peripheral nerve injury". Molecular Pain. 10 (1): 57. doi:10.1186/1744-8069-10-57. PMC 4164746. PMID 25189404.
  32. ↑ Dayalu P, Teener JW (November 2012). "Stiff Person syndrome and other anti-GAD-associated neurologic disorders". Seminars in Neurology. 32 (5): 544–9. doi:10.1055/s-0033-1334477. PMID 23677666.
  33. ↑ Liimatainen S, Honnorat J, Pittock SJ, McKeon A, Manto M, Radtke JR, Hampe CS (April 2018). "GAD65 autoantibody characteristics in patients with co-occurring type 1 diabetes and epilepsy may help identify underlying epilepsy etiologies". Orphanet Journal of Rare Diseases. 13 (1): 55. doi:10.1186/s13023-018-0787-5. PMC 5892043. PMID 29636076.
  34. ↑ Sheng L, Shen D, Luo Y, Sun X, Wang J, Luo T, Zeng Y, Xu J, Deng X, Cheng Y (February 2017). "Exogenous γ-aminobutyric acid treatment affects citrate and amino acid accumulation to improve fruit quality and storage performance of postharvest citrus fruit". Food Chemistry. 216: 138–45. doi:10.1016/j.foodchem.2016.08.024. PMID 27596402.

External links

Retrieved from "https://www.wikidoc.org/index.php?title=Glutamate_decarboxylase&oldid=1541676"