View source for Membrane-bound transcription factor site-1 protease

 {{Infobox_gene}}
'''Membrane-bound transcription factor site-1 protease''', or '''site-1 protease''' ('''S1P''') for short, also known as '''subtilisin/kexin-isozyme 1''' ('''SKI-1'''), is an [[enzyme]] (EC 3.4.21.112) that in humans is encoded by the MBTPS1 [[gene]].<ref name="entrez">{{cite web | title = Entrez Gene: Membrane-bound transcription factor peptidase, site 1 | url = https://www.ncbi.nlm.nih.gov/gene/8720 }}</ref> S1P cleaves the [[endoplasmic reticulum]] loop of [[sterol regulatory element-binding protein]] (SREBP) [[transcription factor]]s.<ref name="pmid10500120">{{cite journal | vauthors = Brown MS, Goldstein JL | title = A proteolytic pathway that controls the cholesterol content of membranes, cells, and blood | journal = Proc. Natl. Acad. Sci. U.S.A. | volume = 96 | issue = 20 | pages = 11041–8 | year = 1999 | pmid = 10500120 | doi = 10.1073/pnas.96.20.11041 | pmc = 34238 }}</ref><ref name="pmid10944850">{{cite journal | vauthors = Nakajima T, Iwaki K, Kodama T, Inazawa J, Emi M | title = Genomic structure and chromosomal mapping of the human site-1 protease (S1P) gene | journal = J. Hum. Genet. | volume = 45 | issue = 4 | pages = 212–7 | year = 2000 | pmid = 10944850 | doi = 10.1007/s100380070029 }}</ref>

== Function ==

This gene encodes a member of the [[subtilisin]]-like proprotein convertase family, which includes proteases that process protein and peptide precursors trafficking through regulated or constitutive branches of the secretory pathway. The encoded protein undergoes an initial autocatalytic processing event in the [[endoplasmic reticulum]] (ER) to generate a [[heterodimer]] which exits the ER and sorts to the cis/medial-[[Golgi apparatus|Golgi]] where a second autocatalytic event takes place and the catalytic activity is acquired. It encodes a type 1 membrane bound protease which is ubiquitously expressed and regulates cholesterol or lipid homeostasis via cleavage of substrates at non-basic residues.<ref name="entrez"/>

== Clinical significance ==

Mutations in this gene may be associated with lysosomal dysfunction.<ref name="entrez"/>

== See also ==
* [[Membrane-bound transcription factor site-2 protease]]

== References ==
{{Reflist}}

== External links ==
* {{MeshName|site-1+protease}}

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{{Serine endopeptidases}}
{{Enzymes}}
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[[Category:EC 3.4.21]]