4j81
Crystal structure of beta'-COP/Insig-1 complexCrystal structure of beta'-COP/Insig-1 complex
FunctionFunction
[COPB2_YEAST] The coatomer is a cytosolic protein complex that binds to dilysine motifs and reversibly associates with Golgi non-clathrin-coated vesicles, which further mediate biosynthetic protein transport from the ER, via the Golgi up to the trans Golgi network. Coatomer complex is required for budding from Golgi membranes, and is essential for the retrograde Golgi-to-ER transport of dilysine-tagged proteins.[1] [INSI1_HUMAN] Mediates feedback control of cholesterol synthesis by controlling SCAP and HMGCR. Functions by blocking the processing of sterol regulatory element-binding proteins (SREBPs). Capable of retaining the SCAP-SREBF2 complex in the ER thus preventing it from escorting SREBPs to the Golgi. Initiates the sterol-mediated ubiquitin-mediated endoplasmic reticulum-associated degradation (ERAD) of HMGCR via recruitment of the reductase to the ubiquitin ligase, AMFR/gp78. May play a role in growth and differentiation of tissues involved in metabolic control. May play a regulatory role during G0/G1 transition of cell growth.[2][3][4][5][6]
About this StructureAbout this Structure
4j81 is a 4 chain structure with sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA.
ReferenceReference
- ↑ Gabriely G, Kama R, Gerst JE. Involvement of specific COPI subunits in protein sorting from the late endosome to the vacuole in yeast. Mol Cell Biol. 2007 Jan;27(2):526-40. Epub 2006 Nov 13. PMID:17101773 doi:MCB.00577-06
- ↑ Yang T, Espenshade PJ, Wright ME, Yabe D, Gong Y, Aebersold R, Goldstein JL, Brown MS. Crucial step in cholesterol homeostasis: sterols promote binding of SCAP to INSIG-1, a membrane protein that facilitates retention of SREBPs in ER. Cell. 2002 Aug 23;110(4):489-500. PMID:12202038
- ↑ Sever N, Yang T, Brown MS, Goldstein JL, DeBose-Boyd RA. Accelerated degradation of HMG CoA reductase mediated by binding of insig-1 to its sterol-sensing domain. Mol Cell. 2003 Jan;11(1):25-33. PMID:12535518
- ↑ Song BL, Sever N, DeBose-Boyd RA. Gp78, a membrane-anchored ubiquitin ligase, associates with Insig-1 and couples sterol-regulated ubiquitination to degradation of HMG CoA reductase. Mol Cell. 2005 Sep 16;19(6):829-40. PMID:16168377 doi:10.1016/j.molcel.2005.08.009
- ↑ Gong Y, Lee JN, Lee PC, Goldstein JL, Brown MS, Ye J. Sterol-regulated ubiquitination and degradation of Insig-1 creates a convergent mechanism for feedback control of cholesterol synthesis and uptake. Cell Metab. 2006 Jan;3(1):15-24. PMID:16399501 doi:10.1016/j.cmet.2005.11.014
- ↑ Gong Y, Lee JN, Brown MS, Goldstein JL, Ye J. Juxtamembranous aspartic acid in Insig-1 and Insig-2 is required for cholesterol homeostasis. Proc Natl Acad Sci U S A. 2006 Apr 18;103(16):6154-9. Epub 2006 Apr 10. PMID:16606821 doi:0601923103