View source for Tropomyosin receptor kinase B

{{Infobox_gene}}
'''Tropomyosin receptor kinase B''' ('''TrkB'''),<ref name="NHM-TrkB">{{cite book |vauthors=Malenka RC, Nestler EJ, Hyman SE |veditors=Sydor A, Brown RY | title = Molecular Neuropharmacology: A Foundation for Clinical Neuroscience | year = 2009 | publisher = McGraw-Hill Medical | location = New York | isbn = 9780071481274 | pages = – | edition = 2nd | chapter = Chapter 8: Atypical neurotransmitters | quote =  Another common feature of neurotrophins is that they produce their physiologic effects by means of the tropomyosin receptor kinase (Trk) receptor family (also known as the tyrosine receptor kinase family).&nbsp;...Trk receptors All neurotrophins bind to a class of highly homologous receptor tyrosine kinases known as Trk receptors, of which three types are known: TrkA, TrkB, and TrkC. These transmembrane receptors are glycoproteins whose molecular masses range from 140 to 145 kDa. Each type of Trk receptor tends to bind specific neurotrophins: TrkA is the receptor for NGF, TrkB the receptor for BDNF and NT-4, and TrkC the receptor for NT-3.However, some overlap in the specificity of these receptors has been noted.}}</ref> also known as '''tyrosine receptor kinase B''',<ref name="NHM-TrkB" /> or '''BDNF/NT-3 growth factors receptor''' or '''neurotrophic tyrosine kinase, receptor, type 2''' is a [[protein]] that in humans is encoded by the ''NTRK2'' [[gene]].<ref name="NHM-TrkB" /><ref name="pmid7789988">{{cite journal | vauthors = Nakagawara A, Liu XG, Ikegaki N, White PS, Yamashiro DJ, Nycum LM, Biegel JA, Brodeur GM | title = Cloning and chromosomal localization of the human TRK-B tyrosine kinase receptor gene (NTRK2) | journal = Genomics | volume = 25 | issue = 2 | pages = 538–46  | date = January 1995 | pmid = 7789988 | doi = 10.1016/0888-7543(95)80055-Q }}</ref>  TrkB is a receptor for [[brain-derived neurotrophic factor]] (BDNF).

== Function ==
Tropomyosin receptor kinase B is the high affinity [[catalytic receptor]] for several "[[neurotrophin]]s", which are small protein growth factors that induce the survival and differentiation of distinct cell populations.  The neurotrophins that activate TrkB are: [[BDNF]] (Brain Derived Neurotrophic Factor), [[neurotrophin-4]] (NT-4), and [[neurotrophin-3]] (NT-3).<ref name="NHM-TrkB" /> As such, TrkB mediates the multiple effects of these neurotrophic factors, which includes neuronal differentiation and survival. Research has shown that activation of the TrkB receptor can lead to down regulation of the KCC2 chloride transporter in cells of the CNS.<ref>{{cite news| title = BDNF-induced TrkB activation down-regulates the K+-Cl- cotransporter KCC2 and impairs neuronal Cl- extrusion.| pmc = 2173387 }}</ref>

The TrkB receptor is part of the large family of receptor tyrosine kinases. A "tyrosine [[kinase]]" is an enzyme which is capable of adding a phosphate group to certain tyrosines on target proteins, or "substrates". A receptor tyrosine kinase is a "tyrosine kinase" which is located at the cellular membrane, and is activated by binding of a ligand to the receptor's extracellular domain. Other examples of tyrosine kinase receptors include the [[insulin receptor]], the IGF1 receptor, the [[MuSK protein]] receptor, the Vascular Endothelial Growth Factor (or VEGF) receptor, etc.

[[Image:TrkB-schema-eng.png|thumb|left|300px|TrkB signaling]]

Currently, there are three TrkB isoforms in the mammalian CNS. The full-length isoform (TK+) is a typical tyrosine kinase receptor, and transduces the BDNF signal via Ras-ERK, PI3K, and PLCγ. In contrast, two truncated isoforms (TK-: T1 and T2) possess the same extracellular domain, transmembrane domain, and first 12 intracellular amino acid sequences as TK+. However, the C-terminal sequences are the isoform-specific (11 and 9 amino acids, respectively). T1 has the original signaling cascade that is involved in the regulation of cell morphology and calcium influx.

== Family members ==
TrkB is part of a sub-family of protein kinases which includes [[TrkA]] and [[TrkC]].  Also, there are other neurotrophic factors structurally related to BDNF: NGF (for [[Nerve Growth Factor]]), NT-3 (for Neurotrophin-3) and NT-4 (for Neurotrophin-4). While TrkB mediates the effects of [[BDNF]], NT-4 and NT-3, TrkA  is bound and thereby activated only by NGF. Further, TrkC binds and is activated by NT-3.

TrkB binds BDNF and NT-4 more strongly than it binds NT-3.  TrkC binds NT-3 more strongly than TrkB does.

== LNGFR ==
There is one other BDNF receptor besides TrkB, called the "LNGFR" (for "[[low-affinity nerve growth factor receptor]]"). As opposed to TrkB, the LNGFR plays a somewhat less clear role in BDNF biology. Some researchers have shown the LNGFR binds and serves as a "sink" for neurotrophins. Cells which express both the LNGFR and the Trk receptors might therefore have a greater activity - since they have a higher "microconcentration" of the neurotrophin. It has also been shown, however, that the LNGFR may signal a cell to die via apoptosis - so therefore cells expressing the LNGFR in the absence of Trk receptors may die rather than live in the presence of a neurotrophin.

== Role in cancer ==
Although originally identified as an oncogenic fusion in 1982,<ref>{{cite journal | vauthors = Pulciani S, Santos E, Lauver AV, Long LK, Aaronson SA, Barbacid M | title = Oncogenes in solid human tumours | journal = Nature | volume = 300 | issue = 5892 | pages = 539–42 | date = December 1982 | pmid = 7144906 | doi = 10.1038/300539a0 }}</ref> only recently has there been a renewed interest in the Trk family as it relates to its role in human cancers because of the identification of NTRK1 (TrkA), NTRK2 (TrkB) and NTRK3 (TrkC) gene fusions and other oncogenic alterations in a number of tumor types. A number of [[Trk inhibitor]]s are (in 2015) in clinical trials and have shown early promise in shrinking human tumors.<ref>{{cite journal | vauthors = Doebele RC, Davis LE, Vaishnavi A, Le AT, Estrada-Bernal A, Keysar S, Jimeno A, Varella-Garcia M, Aisner DL, Li Y, Stephens PJ, Morosini D, Tuch BB, Fernandes M, Nanda N, Low JA | title = An Oncogenic NTRK Fusion in a Patient with Soft-Tissue Sarcoma with Response to the Tropomyosin-Related Kinase Inhibitor LOXO-101 | language = en | journal = Cancer Discovery | volume = 5 | issue = 10 | pages = 1049–57 | date = October 2015 | pmid = 26216294 | pmc = 4635026 | doi = 10.1158/2159-8290.CD-15-0443 | url = http://cancerdiscovery.aacrjournals.org/content/5/10/1049 }}</ref>

=== As a drug target ===
[[Entrectinib]] (formerly RXDX-101) is an investigational drug developed by Ignyta, Inc., which has potential antitumor activity. It is a selective pan-trk receptor [[tyrosine kinase inhibitor]] (TKI) targeting gene fusions in [[Tropomyosin receptor kinase A|trkA]], trkB (this gene), and [[Tropomyosin receptor kinase C|trkC]] (respectively, coded by [[Tropomyosin receptor kinase A|NTRK1]], NTRK2, and [[Tropomyosin receptor kinase C|NTRK3]] genes) that is currently in phase 2 clinical testing.<ref>{{cite web |url= https://www.sciencedaily.com/releases/2016/04/160418092429.htm |title= Promising entrectinib clinical trial data |work= ScienceDaily |date= 18 April 2016 }}</ref>

==Ligands==

=== Agonists ===
{{div col|colwidth=20em}}
* [[3,7-Dihydroxyflavone]]
* [[3,7,8,2'-Tetrahydroxyflavone]]
* [[4'-Dimethylamino-7,8-dihydroxyflavone]]<ref name="pmid21073191">{{cite journal | vauthors = Liu X, Chan CB, Jang SW, Pradoldej S, Huang J, He K, Phun LH, France S, Xiao G, Jia Y, Luo HR, Ye K | title = A synthetic 7,8-dihydroxyflavone derivative promotes neurogenesis and exhibits potent antidepressant effect | journal = J. Med. Chem. | volume = 53 | issue = 23 | pages = 8274–86  | date = November 2010 | pmid = 21073191 | doi = 10.1021/jm101206p | pmc=3150605}}</ref>
* [[7,3′-Dihydroxyflavone]]
* [[7,8-Dihydroxyflavone]]
* [[7,8,2'-Trihydroxyflavone]]
* [[7,8,3'-Trihydroxyflavone]]
* [[Amitriptyline]]<ref name="pmid19549602">{{cite journal | vauthors = Jang SW, Liu X, Chan CB, Weinshenker D, Hall RA, Xiao G, Ye K | title = Amitriptyline is a TrkA and TrkB receptor agonist that promotes TrkA/TrkB heterodimerization and has potent neurotrophic activity | journal = Chem. Biol. | volume = 16 | issue = 6 | pages = 644–56 | year = 2009 | pmid = 19549602 | pmc = 2844702 | doi = 10.1016/j.chembiol.2009.05.010 }}</ref>
* [[Brain-derived neurotrophic factor]] (BDNF)
* [[Deoxygedunin]]<ref name="pmid20644624">{{cite journal | vauthors = Jang SW, Liu X, Chan CB, France SA, Sayeed I, Tang W, Lin X, Xiao G, Andero R, Chang Q, Ressler KJ, Ye K | title = Deoxygedunin, a natural product with potent neurotrophic activity in mice | journal = PLoS ONE | volume = 5 | issue = 7 | pages = e11528 | year = 2010 | pmid = 20644624 | pmc = 2903477 | doi = 10.1371/journal.pone.0011528 }}</ref>
* [[Deprenyl]]
* [[Diosmetin]]
* [[DMAQ-B1]]
* [[HIOC]]
* [[LM22A-4]]
* [[N-Acetylserotonin]]
* [[Neurotrophin-3]] (NT-3)
* [[Neurotrophin-4]] (NT-4)
* [[Norwogonin|Norwogonin (5,7,8-THF)]]
* [[R7 (drug)|R7]]
* [[TDP6]]
{{Div col end}}

===Antagonists===
{{div col|colwidth=20em}}
* [[ANA-12]]
* [[Cyclotraxin B]]
* [[Gossypetin|Gossypetin (3,5,7,8,3',4'-HHF)]]
{{Div col end}}

== Interactions ==
TrkB has been shown to [[Protein-protein interaction|interact]] with:
{{div col|colwidth=20em}}
* [[Brain-derived neurotrophic factor]] (BDNF),<ref name="pmid9312147">{{cite journal | vauthors = Haniu M, Montestruque S, Bures EJ, Talvenheimo J, Toso R, Lewis-Sandy S, Welcher AA, Rohde MF | title = Interactions between brain-derived neurotrophic factor and the TRKB receptor. Identification of two ligand binding domains in soluble TRKB by affinity separation and chemical cross-linking | journal = J. Biol. Chem. | volume = 272 | issue = 40 | pages = 25296–303  | date = October 1997 | pmid = 9312147 | doi = 10.1074/jbc.272.40.25296 }}</ref><ref name="pmid11855816">{{cite journal | vauthors = Naylor RL, Robertson AG, Allen SJ, Sessions RB, Clarke AR, Mason GG, Burston JJ, Tyler SJ, Wilcock GK, Dawbarn D | title = A discrete domain of the human TrkB receptor defines the binding sites for BDNF and NT-4 | journal = Biochem. Biophys. Res. Commun. | volume = 291 | issue = 3 | pages = 501–7  | date = March 2002 | pmid = 11855816 | doi = 10.1006/bbrc.2002.6468 }}</ref>
* [[FYN]],<ref name="pmid9648856">{{cite journal | vauthors = Iwasaki Y, Gay B, Wada K, Koizumi S | title = Association of the Src family tyrosine kinase Fyn with TrkB | journal = J. Neurochem. | volume = 71 | issue = 1 | pages = 106–11  | date = July 1998 | pmid = 9648856 | doi = 10.1046/j.1471-4159.1998.71010106.x }}</ref>
* [[NCK2]],<ref name=pmid12074588/>
* [[PLCG1]],<ref name="pmid12074588">{{cite journal | vauthors = Suzuki S, Mizutani M, Suzuki K, Yamada M, Kojima M, Hatanaka H, Koizumi S | title = Brain-derived neurotrophic factor promotes interaction of the Nck2 adaptor protein with the TrkB tyrosine kinase receptor | journal = Biochem. Biophys. Res. Commun. | volume = 294 | issue = 5 | pages = 1087–92  | date = June 2002 | pmid = 12074588 | doi = 10.1016/S0006-291X(02)00606-X }}</ref><ref name="pmid10092678">{{cite journal | vauthors = Meakin SO, MacDonald JI, Gryz EA, Kubu CJ, Verdi JM | title = The signaling adapter FRS-2 competes with Shc for binding to the nerve growth factor receptor TrkA. A model for discriminating proliferation and differentiation | journal = J. Biol. Chem. | volume = 274 | issue = 14 | pages = 9861–70  | date = April 1999 | pmid = 10092678 | doi = 10.1074/jbc.274.14.9861 }}</ref>
* [[Sequestosome 1]],<ref name="pmid12471037">{{cite journal | vauthors = Geetha T, Wooten MW | title = Association of the atypical protein kinase C-interacting protein p62/ZIP with nerve growth factor receptor TrkA regulates receptor trafficking and Erk5 signaling | journal = J. Biol. Chem. | volume = 278 | issue = 7 | pages = 4730–9  | date = February 2003 | pmid = 12471037 | doi = 10.1074/jbc.M208468200 }}</ref> and
* [[SHC3]].<ref name=pmid12074588/><ref name="pmid9507002">{{cite journal | vauthors = Nakamura T, Muraoka S, Sanokawa R, Mori N | title = N-Shc and Sck, two neuronally expressed Shc adapter homologs. Their differential regional expression in the brain and roles in neurotrophin and Src signaling | journal = J. Biol. Chem. | volume = 273 | issue = 12 | pages = 6960–7  | date = March 1998 | pmid = 9507002 | doi = 10.1074/jbc.273.12.6960 }}</ref>
{{Div col end}}

== See also ==
* [[Trk receptor]]

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

== Further reading ==
{{Refbegin|33em}}
* {{cite journal | vauthors = Klein R, Conway D, Parada LF, Barbacid M | title = The trkB tyrosine protein kinase gene codes for a second neurogenic receptor that lacks the catalytic kinase domain | journal = Cell | volume = 61 | issue = 4 | pages = 647–56  | date = May 1990 | pmid = 2160854 | doi = 10.1016/0092-8674(90)90476-U }}
* {{cite journal | vauthors = Squinto SP, Stitt TN, Aldrich TH, Davis S, Bianco SM, Radziejewski C, Glass DJ, Masiakowski P, Furth ME, Valenzuela DM | title = trkB encodes a functional receptor for brain-derived neurotrophic factor and neurotrophin-3 but not nerve growth factor | journal = Cell | volume = 65 | issue = 5 | pages = 885–93  | date = May 1991 | pmid = 1710174 | doi = 10.1016/0092-8674(91)90395-F }}
* {{cite journal | vauthors = Rose CR, Blum R, Pichler B, Lepier A, Kafitz KW, Konnerth A | title = Truncated TrkB-T1 mediates neurotrophin-evoked calcium signalling in glia cells | journal = Nature | volume = 426 | issue = 6962 | pages = 74–8  | date = November 2003 | pmid = 14603320 | doi = 10.1038/nature01983 }}
* {{cite journal | vauthors = Ohira K, Kumanogoh H, Sahara Y, Homma KJ, Hirai H, Nakamura S, Hayashi M | title = A truncated tropomyosin-related kinase B receptor, T1, regulates glial cell morphology via Rho GDP dissociation inhibitor 1 | journal = J. Neurosci. | volume = 25 | issue = 6 | pages = 1343–53  | date = February 2005 | pmid = 15703388 | doi = 10.1523/JNEUROSCI.4436-04.2005 }}
* {{cite journal | vauthors = Yamada K, Nabeshima T | title = Brain-derived neurotrophic factor/TrkB signaling in memory processes | journal = J. Pharmacol. Sci. | volume = 91 | issue = 4 | pages = 267–70 | year = 2003 | pmid = 12719654 | doi = 10.1254/jphs.91.267 }}
* {{cite journal | vauthors = Soppet D, Escandon E, Maragos J, Middlemas DS, Reid SW, Blair J, Burton LE, Stanton BR, Kaplan DR, Hunter T, Nikolics K, Parada LF | title = The neurotrophic factors brain-derived neurotrophic factor and neurotrophin-3 are ligands for the trkB tyrosine kinase receptor | journal = Cell | volume = 65 | issue = 5 | pages = 895–903 | year = 1991 | pmid = 1645620 | doi = 10.1016/0092-8674(91)90396-G }}
* {{cite journal | vauthors = Squinto SP, Stitt TN, Aldrich TH, Davis S, Bianco SM, Radziejewski C, Glass DJ, Masiakowski P, Furth ME, Valenzuela DM | title = trkB encodes a functional receptor for brain-derived neurotrophic factor and neurotrophin-3 but not nerve growth factor | journal = Cell | volume = 65 | issue = 5 | pages = 885–93 | year = 1991 | pmid = 1710174 | doi = 10.1016/0092-8674(91)90395-F }}
* {{cite journal | vauthors = Haniu M, Talvenheimo J, Le J, Katta V, Welcher A, Rohde MF | title = Extracellular domain of neurotrophin receptor trkB: disulfide structure, N-glycosylation sites, and ligand binding | journal = Arch. Biochem. Biophys. | volume = 322 | issue = 1 | pages = 256–64 | year = 1995 | pmid = 7574684 | doi = 10.1006/abbi.1995.1460 }}
* {{cite journal | vauthors = Ip NY, Stitt TN, Tapley P, Klein R, Glass DJ, Fandl J, Greene LA, Barbacid M, Yancopoulos GD | title = Similarities and differences in the way neurotrophins interact with the Trk receptors in neuronal and nonneuronal cells | journal = Neuron | volume = 10 | issue = 2 | pages = 137–49 | year = 1993 | pmid = 7679912 | doi = 10.1016/0896-6273(93)90306-C }}
* {{cite journal | vauthors = Slaugenhaupt SA, Blumenfeld A, Liebert CB, Mull J, Lucente DE, Monahan M, Breakefield XO, Maayan C, Parada L, Axelrod FB | title = The human gene for neurotrophic tyrosine kinase receptor type 2 (NTRK2) is located on chromosome 9 but is not the familial dysautonomia gene | journal = Genomics | volume = 25 | issue = 3 | pages = 730–2 | year = 1995 | pmid = 7759111 | doi = 10.1016/0888-7543(95)80019-I }}
* {{cite journal | vauthors = Shelton DL, Sutherland J, Gripp J, Camerato T, Armanini MP, Phillips HS, Carroll K, Spencer SD, Levinson AD | title = Human trks: molecular cloning, tissue distribution, and expression of extracellular domain immunoadhesins | journal = J. Neurosci. | volume = 15 | issue = 1 Pt 2 | pages = 477–91 | year = 1995 | pmid = 7823156 | doi =  }}
* {{cite journal | vauthors = Allen SJ, Dawbarn D, Eckford SD, Wilcock GK, Ashcroft M, Colebrook SM, Feeney R, MacGowan SH | title = Cloning of a non-catalytic form of human trkB and distribution of messenger RNA for trkB in human brain | journal = Neuroscience | volume = 60 | issue = 3 | pages = 825–34 | year = 1994 | pmid = 7936202 | doi = 10.1016/0306-4522(94)90507-X }}
* {{cite journal | vauthors = Rydén M, Ibáñez CF | title = Binding of neurotrophin-3 to p75LNGFR, TrkA, and TrkB mediated by a single functional epitope distinct from that recognized by trkC | journal = J. Biol. Chem. | volume = 271 | issue = 10 | pages = 5623–7 | year = 1996 | pmid = 8621424 | doi = 10.1074/jbc.271.10.5623 }}
* {{cite journal | vauthors = Yamamoto M, Sobue G, Yamamoto K, Terao S, Mitsuma T | title = Expression of mRNAs for neurotrophic factors (NGF, BDNF, NT-3, and GDNF) and their receptors (p75NGFR, trkA, trkB, and trkC) in the adult human peripheral nervous system and nonneural tissues | journal = Neurochem. Res. | volume = 21 | issue = 8 | pages = 929–38 | year = 1996 | pmid = 8895847 | doi = 10.1007/BF02532343 }}
* {{cite journal | vauthors = Valent A, Danglot G, Bernheim A | title = Mapping of the tyrosine kinase receptors trkA (NTRK1), trkB (NTRK2) and trkC(NTRK3) to human chromosomes 1q22, 9q22 and 15q25 by fluorescence in situ hybridization | journal = Eur. J. Hum. Genet. | volume = 5 | issue = 2 | pages = 102–4 | year = 1997 | pmid = 9195161 | doi =  }}
* {{cite journal | vauthors = Haniu M, Montestruque S, Bures EJ, Talvenheimo J, Toso R, Lewis-Sandy S, Welcher AA, Rohde MF | title = Interactions between brain-derived neurotrophic factor and the TRKB receptor. Identification of two ligand binding domains in soluble TRKB by affinity separation and chemical cross-linking | journal = J. Biol. Chem. | volume = 272 | issue = 40 | pages = 25296–303 | year = 1997 | pmid = 9312147 | doi = 10.1074/jbc.272.40.25296 }}
* {{cite journal | vauthors = Nakamura T, Muraoka S, Sanokawa R, Mori N | title = N-Shc and Sck, two neuronally expressed Shc adapter homologs. Their differential regional expression in the brain and roles in neurotrophin and Src signaling | journal = J. Biol. Chem. | volume = 273 | issue = 12 | pages = 6960–7 | year = 1998 | pmid = 9507002 | doi = 10.1074/jbc.273.12.6960 }}
* {{cite journal | vauthors = Hackett SF, Friedman Z, Freund J, Schoenfeld C, Curtis R, DiStefano PS, Campochiaro PA | title = A splice variant of trkB and brain-derived neurotrophic factor are co-expressed in retinal pigmented epithelial cells and promote differentiated characteristics | journal = Brain Res. | volume = 789 | issue = 2 | pages = 201–12 | year = 1998 | pmid = 9573364 | doi = 10.1016/S0006-8993(97)01440-6 }}
* {{cite journal | vauthors = Iwasaki Y, Gay B, Wada K, Koizumi S | title = Association of the Src family tyrosine kinase Fyn with TrkB | journal = J. Neurochem. | volume = 71 | issue = 1 | pages = 106–11 | year = 1998 | pmid = 9648856 | doi = 10.1046/j.1471-4159.1998.71010106.x }}
* {{cite journal | vauthors = Qian X, Riccio A, Zhang Y, Ginty DD | title = Identification and characterization of novel substrates of Trk receptors in developing neurons | journal = Neuron | volume = 21 | issue = 5 | pages = 1017–29 | year = 1998 | pmid = 9856458 | doi = 10.1016/S0896-6273(00)80620-0 }}
* {{cite journal | vauthors = Bibel M, Hoppe E, Barde YA | title = Biochemical and functional interactions between the neurotrophin receptors trk and p75NTR | journal = EMBO J. | volume = 18 | issue = 3 | pages = 616–22 | year = 1999 | pmid = 9927421 | pmc = 1171154 | doi = 10.1093/emboj/18.3.616 }}
* {{cite journal | vauthors = Yamada M, Ohnishi H, Sano S, Araki T, Nakatani A, Ikeuchi T, Hatanaka H | title = Brain-derived neurotrophic factor stimulates interactions of Shp2 with phosphatidylinositol 3-kinase and Grb2 in cultured cerebral cortical neurons | journal = J. Neurochem. | volume = 73 | issue = 1 | pages = 41–9 | year = 1999 | pmid = 10386953 | doi = 10.1046/j.1471-4159.1999.0730041.x }}
* {{cite journal | vauthors = Ultsch MH, Wiesmann C, Simmons LC, Henrich J, Yang M, Reilly D, Bass SH, de Vos AM | title = Crystal structures of the neurotrophin-binding domain of TrkA, TrkB and TrkC | journal = J. Mol. Biol. | volume = 290 | issue = 1 | pages = 149–59 | year = 1999 | pmid = 10388563 | doi = 10.1006/jmbi.1999.2816 }}
{{Refend}}

== External links ==
* [https://www.newscientist.com/channel/being-human/brain/mg19325864.500-memories-are-made-of-this-molecule.html Memories are made of this molecule] - New Scientist, 15 January 2007.

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{{DEFAULTSORT:Trkb}}
[[Category:Tyrosine kinase receptors]]
[[Category:Developmental neuroscience]]