Proprotein convertase subtilisin/kexin type 9, also known as PCSK9, is an enzyme which in humans is encoded by the PCSK9 gene[1] with orthologs found across many species.

Function

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This gene encodes a proprotein convertase belonging to the proteinase K subfamily of the secretory subtilase family. The encoded protein is synthesized as a soluble zymogen that undergoes autocatalytic intramolecular processing in the endoplasmic reticulum. The protein may function as a proprotein convertase.

This protein plays a major regulatory role in cholesterol homeostasis. PCSK9 binds to the epidermal growth factor-like repeat A (EGF-A) domain of the low-density lipoprotein receptor (LDLR), inducing LDLR degradation. Reduced LDLR levels result in decreased metabolism of low-density lipoproteins, which could lead to hypercholesterolemia.

PCSK9 may also have a role in the differentiation of cortical neurons.[1]

Clinical significance

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Several variants of PCSK9 have also been shown to significantly reduce circulating cholesterol. Some variants, which only reduce cholesterol by 15% in whites, has been shown to produce a concurrent reduction in coronary heart disease by 50%,[citation needed] which has major implications for public health.

Inhibition of PCSK9 function is currently being explored as a means of lowering cholesterol levels.[2][3][4][5]

Alnylam Pharmaceuticals has recently shown, in initial clinical trials, positive results of ALN-PCS, which acts by means of RNA interference, as an effective means of PCSK9 inhibition.[6]

Mutations in this gene have been associated with a rare form of autosomal dominant familial hypercholesterolemia (HCHOLA3).[7][8][9] The mutations appear to cause the disease by increasing its protease activity, reducing LDL receptor levels and thereby preventing the uptake of cholesterol into the cells.[8]

References

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  1. ^ a b Seidah NG, Benjannet S, Wickham L, Marcinkiewicz J, Jasmin SB, Stifani S, Basak A, Prat A, Chretien M (February 2003). "The secretory proprotein convertase neural apoptosis-regulated convertase 1 (NARC-1): Liver regeneration and neuronal differentiation". Proc. Natl. Acad. Sci. U.S.A. 100 (3): 928–33. doi:10.1073/pnas.0335507100. PMC 298703. PMID 12552133.{{cite journal}}: CS1 maint: date and year (link) CS1 maint: multiple names: authors list (link)
  2. ^ Lopez D (2008). "Inhibition of PCSK9 as a novel strategy for the treatment of hypercholesterolemia". Drug News Perspect. 21 (6): 323–30. doi:10.1358/dnp.2008.21.6.1246795. PMID 18836590.
  3. ^ Steinberg D, Witztum JL (June 2009). "Inhibition of PCSK9: A powerful weapon for achieving ideal LDL cholesterol levels". Proc. Natl. Acad. Sci. U.S.A. 106 (24): 9546–7. doi:10.1073/pnas.0904560106. PMC 2701045. PMID 19506257.{{cite journal}}: CS1 maint: date and year (link)
  4. ^ Mayer G, Poirier S, Seidah NG (November 2008). "Annexin A2 is a C-terminal PCSK9-binding protein that regulates endogenous low density lipoprotein receptor levels". J. Biol. Chem. 283 (46): 31791–801. doi:10.1074/jbc.M805971200. PMID 18799458.{{cite journal}}: CS1 maint: date and year (link) CS1 maint: multiple names: authors list (link)
  5. ^ "Bristol-Myers Squibb selects Isis drug targeting PCSK9 as development candidate for prevention and treatment of cardiovascular disease". Press Release. FierceBiotech. 2008-04-08. Retrieved 2010-09-18.
  6. ^ "Alnylam Reports Positive Preliminary Clinical Results for ALN-PCS, an RNAi Therapeutic Targeting PCSK9 for the Treatment of Severe Hypercholesterolemia". Press Release. BusinessWire. 2011-01-04. Retrieved 2011-01-04.
  7. ^ "Entrez Gene: PCSK9 proprotein convertase subtilisin/kexin type 9".
  8. ^ a b Abifadel M, Varret M, Rabès JP, Allard D, Ouguerram K, Devillers M, Cruaud C, Benjannet S, Wickham L, Erlich D, Derré A, Villéger 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 (June 2003). "Mutations in PCSK9 cause autosomal dominant hypercholesterolemia". Nat. Genet. 34 (2): 154–6. doi:10.1038/ng1161. PMID 12730697.{{cite journal}}: CS1 maint: date and year (link) CS1 maint: multiple names: authors list (link)
  9. ^ Dubuc G, Chamberland A, Wassef H, Davignon J, Seidah NG, Bernier L, Prat A (August 2004). "Statins upregulate PCSK9, the gene encoding the proprotein convertase neural apoptosis-regulated convertase-1 implicated in familial hypercholesterolemia". Arterioscler. Thromb. Vasc. Biol. 24 (8): 1454–9. doi:10.1161/01.ATV.0000134621.14315.43. PMID 15178557.{{cite journal}}: CS1 maint: date and year (link) CS1 maint: multiple names: authors list (link)

Further reading

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