| Structural highlights
Disease
[PCSK9_HUMAN] Defects in PCSK9 are the cause of hypercholesterolemia autosomal dominant type 3 (HCHOLA3) [MIM:603776]. A familial condition characterized by elevated circulating cholesterol contained in either low-density lipoproteins alone or also in very-low-density lipoproteins.[1]
Function
[PCSK9_HUMAN] Crucial player in the regulation of plasma cholesterol homeostasis. Binds to low-density lipid receptor family members: low density lipoprotein receptor (LDLR), very low density lipoprotein receptor (VLDLR), apolipoprotein E receptor (LRP1/APOER) and apolipoprotein receptor 2 (LRP8/APOER2), and promotes their degradation in intracellular acidic compartments. Acts via a non-proteolytic mechanism to enhance the degradation of the hepatic LDLR through a clathrin LDLRAP1/ARH-mediated pathway. May prevent the recycling of LDLR from endosomes to the cell surface or direct it to lysosomes for degradation. Can induce ubiquitination of LDLR leading to its subsequent degradation. Inhibits intracellular degradation of APOB via the autophagosome/lysosome pathway in a LDLR-independent manner. Involved in the disposal of non-acetylated intermediates of BACE1 in the early secretory pathway. Inhibits epithelial Na(+) channel (ENaC)-mediated Na(+) absorption by reducing ENaC surface expression primarily by increasing its proteasomal degradation. Regulates neuronal apoptosis via modulation of LRP8/APOER2 levels and related anti-apoptotic signaling pathways.[2] [3] [4] [5] [6] [7] [8]
Publication Abstract from PubMed
Proprotein convertase subtilisin-like/kexin type 9 regulates LDL cholesterol levels by inhibiting LDL-receptor mediated cellular LDL uptake. We have identified a fragment of antibody (Fab) 1D05 which binds PCSK9 with nanomolar affinity. The fully human antibody 1D05-IgG2 completely blocks the inhibitory effects of wildtype PCSK9 and two gain-of-function human PCSK9 mutants, S127R and D374Y. The crystal structure of 1D05-Fab bound to PCSK9 reveals that 1D05-Fab binds to an epitope on the PCSK9 catalytic domain which includes the entire LDL-receptor EGF(A) binding site. Notably, the 1D05-Fab CDR-H3 and CDR-H2 loops structurally mimic the EGF(A) domain of LDL-receptor. In a transgenic mouse model (CETP/LDL-receptor-hemi) with plasma lipid and PCSK9 profiles comparable to those of humans, 1D05-IgG2 reduces plasma LDL cholesterol 40% and raises hepatic LDL-receptor protein levels approximately five fold. Similarly, in healthy rhesus monkeys, 1D05-IgG2 effectively reduces LDL cholesterol 20-50% for over two weeks, despite its relatively short terminal half life (t1/2=3.2 days). Importantly, the decrease in circulating LDL cholesterol corresponds closely to the reduction in free PCSK9 levels. Together these results clearly demonstrate the LDL-lowering effect of the neutralizing anti-PCSK9 1D05-IgG2 is mediated by reducing the amount of PCSK9 that can bind to the LDL-receptor.
A proprotein convertase subtilisin-like/kexin type 9 (PCSK9)-binding antibody that structurally mimics the EGF(A) domain of LDL-receptor reduces free circulating PCSK9 and LDL-cholesterol.,Ni YG, Di Marco S, Condra JH, Peterson LB, Wang W, Wang F, Pandit S, Hammond HA, Rosa R, Cummings RT, Wood DD, Liu X, Bottomley MJ, Shen X, Cubbon RM, Wang SP, Johns DG, Volpari C, Hamuro L, Chin J, Huang L, Zhao JZ, Vitelli S, Haytko P, Wisniewski D, Mitnaul LJ, Sparrow CP, Hubbard B, Carfi A, Sitlani A J Lipid Res. 2010 Oct 19. PMID:20959675[9]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Abifadel M, Varret M, Rabes JP, Allard D, Ouguerram K, Devillers M, Cruaud C, Benjannet S, Wickham L, Erlich D, Derre A, Villeger L, Farnier M, Beucler I, Bruckert E, Chambaz J, Chanu B, Lecerf JM, Luc G, Moulin P, Weissenbach J, Prat A, Krempf M, Junien C, Seidah NG, Boileau C. Mutations in PCSK9 cause autosomal dominant hypercholesterolemia. Nat Genet. 2003 Jun;34(2):154-6. PMID:12730697 doi:10.1038/ng1161
- ↑ Nassoury N, Blasiole DA, Tebon Oler A, Benjannet S, Hamelin J, Poupon V, McPherson PS, Attie AD, Prat A, Seidah NG. The cellular trafficking of the secretory proprotein convertase PCSK9 and its dependence on the LDLR. Traffic. 2007 Jun;8(6):718-32. Epub 2007 Apr 25. PMID:17461796 doi:10.1111/j.1600-0854.2007.00562.x
- ↑ Fan D, Yancey PG, Qiu S, Ding L, Weeber EJ, Linton MF, Fazio S. Self-association of human PCSK9 correlates with its LDLR-degrading activity. Biochemistry. 2008 Feb 12;47(6):1631-9. doi: 10.1021/bi7016359. Epub 2008 Jan 16. PMID:18197702 doi:10.1021/bi7016359
- ↑ Jonas MC, Costantini C, Puglielli L. PCSK9 is required for the disposal of non-acetylated intermediates of the nascent membrane protein BACE1. EMBO Rep. 2008 Sep;9(9):916-22. doi: 10.1038/embor.2008.132. Epub 2008 Jul 25. PMID:18660751 doi:10.1038/embor.2008.132
- ↑ Poirier S, Mayer G, Benjannet S, Bergeron E, Marcinkiewicz J, Nassoury N, Mayer H, Nimpf J, Prat A, Seidah NG. The proprotein convertase PCSK9 induces the degradation of low density lipoprotein receptor (LDLR) and its closest family members VLDLR and ApoER2. J Biol Chem. 2008 Jan 25;283(4):2363-72. Epub 2007 Nov 26. PMID:18039658 doi:10.1074/jbc.M708098200
- ↑ Chen Y, Wang H, Yu L, Yu X, Qian YW, Cao G, Wang J. Role of ubiquitination in PCSK9-mediated low-density lipoprotein receptor degradation. Biochem Biophys Res Commun. 2011 Nov 25;415(3):515-8. doi:, 10.1016/j.bbrc.2011.10.110. Epub 2011 Nov 2. PMID:22074827 doi:10.1016/j.bbrc.2011.10.110
- ↑ Sun H, Samarghandi A, Zhang N, Yao Z, Xiong M, Teng BB. Proprotein convertase subtilisin/kexin type 9 interacts with apolipoprotein B and prevents its intracellular degradation, irrespective of the low-density lipoprotein receptor. Arterioscler Thromb Vasc Biol. 2012 Jul;32(7):1585-95. doi:, 10.1161/ATVBAHA.112.250043. Epub 2012 May 10. PMID:22580899 doi:10.1161/ATVBAHA.112.250043
- ↑ Sharotri V, Collier DM, Olson DR, Zhou R, Snyder PM. Regulation of epithelial sodium channel trafficking by proprotein convertase subtilisin/kexin type 9 (PCSK9). J Biol Chem. 2012 Jun 1;287(23):19266-74. doi: 10.1074/jbc.M112.363382. Epub 2012, Apr 9. PMID:22493497 doi:10.1074/jbc.M112.363382
- ↑ Ni YG, Di Marco S, Condra JH, Peterson LB, Wang W, Wang F, Pandit S, Hammond HA, Rosa R, Cummings RT, Wood DD, Liu X, Bottomley MJ, Shen X, Cubbon RM, Wang SP, Johns DG, Volpari C, Hamuro L, Chin J, Huang L, Zhao JZ, Vitelli S, Haytko P, Wisniewski D, Mitnaul LJ, Sparrow CP, Hubbard B, Carfi A, Sitlani A. A proprotein convertase subtilisin-like/kexin type 9 (PCSK9)-binding antibody that structurally mimics the EGF(A) domain of LDL-receptor reduces free circulating PCSK9 and LDL-cholesterol. J Lipid Res. 2010 Oct 19. PMID:20959675 doi:10.1194/jlr.M011445
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