| Structural highlights
Disease
CO3_HUMAN Defects in C3 are the cause of complement component 3 deficiency (C3D) [MIM:613779. A rare defect of the complement classical pathway. Patients develop recurrent, severe, pyogenic infections because of ineffective opsonization of pathogens. Some patients may also develop autoimmune disorders, such as arthralgia and vasculitic rashes, lupus-like syndrome and membranoproliferative glomerulonephritis.[1] [2] [3] [4] [5] [:] Genetic variation in C3 is associated with susceptibility to age-related macular degeneration type 9 (ARMD9) [MIM:611378. ARMD is a multifactorial eye disease and the most common cause of irreversible vision loss in the developed world. In most patients, the disease is manifest as ophthalmoscopically visible yellowish accumulations of protein and lipid that lie beneath the retinal pigment epithelium and within an elastin-containing structure known as Bruch membrane.[6] [7] Defects in C3 are a cause of susceptibility to hemolytic uremic syndrome atypical type 5 (AHUS5) [MIM:612925. An atypical form of hemolytic uremic syndrome. It is a complex genetic disease characterized by microangiopathic hemolytic anemia, thrombocytopenia, renal failure and absence of episodes of enterocolitis and diarrhea. In contrast to typical hemolytic uremic syndrome, atypical forms have a poorer prognosis, with higher death rates and frequent progression to end-stage renal disease. Note=Susceptibility to the development of atypical hemolytic uremic syndrome can be conferred by mutations in various components of or regulatory factors in the complement cascade system. Other genes may play a role in modifying the phenotype.[8] [9] [10] Note=Increased levels of C3 and its cleavage product ASP, are associated with obesity, diabetes and coronary heart disease. Short-term endurance training reduces baseline ASP levels and subsequently fat storage.[11]
Function
CO3_HUMAN C3 plays a central role in the activation of the complement system. Its processing by C3 convertase is the central reaction in both classical and alternative complement pathways. After activation C3b can bind covalently, via its reactive thioester, to cell surface carbohydrates or immune aggregates.[12] [13] [14] [15] [16] [17] [18] [19] Derived from proteolytic degradation of complement C3, C3a anaphylatoxin is a mediator of local inflammatory process. It induces the contraction of smooth muscle, increases vascular permeability and causes histamine release from mast cells and basophilic leukocytes.[20] [21] [22] [23] [24] [25] [26] [27] Acylation stimulating protein (ASP): adipogenic hormone that stimulates triglyceride (TG) synthesis and glucose transport in adipocytes, regulating fat storage and playing a role in postprandial TG clearance. Appears to stimulate TG synthesis via activation of the PLC, MAPK and AKT signaling pathways. Ligand for GPR77. Promotes the phosphorylation, ARRB2-mediated internalization and recycling of GPR77.[28] [29] [30] [31] [32] [33] [34] [35]
Publication Abstract from PubMed
The complement system labels microbes and host debris for clearance. Degradation of surface-bound C3b is pivotal to direct immune responses and protect host cells. How the serine protease factor I (FI), assisted by regulators, cleaves either two or three distant peptide bonds in the CUB domain of C3b remains unclear. We present a crystal structure of C3b in complex with FI and regulator factor H (FH; domains 1-4 with 19-20). FI binds C3b-FH between FH domains 2 and 3 and a reoriented C3b C-terminal domain and docks onto the first scissile bond, while stabilizing its catalytic domain for proteolytic activity. One cleavage in C3b does not affect its overall structure, whereas two cleavages unfold CUB and dislodge the thioester-containing domain (TED), affecting binding of regulators and thereby determining the number of cleavages. These data explain how FI generates late-stage opsonins iC3b or C3dg in a context-dependent manner, to react to foreign, danger or healthy self signals.
Regulator-dependent mechanisms of C3b processing by factor I allow differentiation of immune responses.,Xue X, Wu J, Ricklin D, Forneris F, Di Crescenzio P, Schmidt CQ, Granneman J, Sharp TH, Lambris JD, Gros P Nat Struct Mol Biol. 2017 Aug;24(8):643-651. doi: 10.1038/nsmb.3427. Epub 2017, Jul 3. PMID:28671664[36]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Onat A, Hergenc G, Can G, Kaya Z, Yuksel H. Serum complement C3: a determinant of cardiometabolic risk, additive to the metabolic syndrome, in middle-aged population. Metabolism. 2010 May;59(5):628-34. doi: 10.1016/j.metabol.2009.09.006. Epub 2009 , Nov 14. PMID:19913840 doi:10.1016/j.metabol.2009.09.006
- ↑ Nagar B, Jones RG, Diefenbach RJ, Isenman DE, Rini JM. X-ray crystal structure of C3d: a C3 fragment and ligand for complement receptor 2. Science. 1998 May 22;280(5367):1277-81. PMID:9596584
- ↑ Szakonyi G, Guthridge JM, Li D, Young K, Holers VM, Chen XS. Structure of complement receptor 2 in complex with its C3d ligand. Science. 2001 Jun 1;292(5522):1725-8. PMID:11387479 doi:10.1126/science.1059118
- ↑ Gilbert HE, Eaton JT, Hannan JP, Holers VM, Perkins SJ. Solution structure of the complex between CR2 SCR 1-2 and C3d of human complement: an X-ray scattering and sedimentation modelling study. J Mol Biol. 2005 Feb 25;346(3):859-73. Epub 2005 Jan 12. PMID:15713468 doi:10.1016/j.jmb.2004.12.006
- ↑ Singer L, Whitehead WT, Akama H, Katz Y, Fishelson Z, Wetsel RA. Inherited human complement C3 deficiency. An amino acid substitution in the beta-chain (ASP549 to ASN) impairs C3 secretion. J Biol Chem. 1994 Nov 11;269(45):28494-9. PMID:7961791
- ↑ Onat A, Hergenc G, Can G, Kaya Z, Yuksel H. Serum complement C3: a determinant of cardiometabolic risk, additive to the metabolic syndrome, in middle-aged population. Metabolism. 2010 May;59(5):628-34. doi: 10.1016/j.metabol.2009.09.006. Epub 2009 , Nov 14. PMID:19913840 doi:10.1016/j.metabol.2009.09.006
- ↑ Yates JR, Sepp T, Matharu BK, Khan JC, Thurlby DA, Shahid H, Clayton DG, Hayward C, Morgan J, Wright AF, Armbrecht AM, Dhillon B, Deary IJ, Redmond E, Bird AC, Moore AT. Complement C3 variant and the risk of age-related macular degeneration. N Engl J Med. 2007 Aug 9;357(6):553-61. Epub 2007 Jul 18. PMID:17634448 doi:NEJMoa072618
- ↑ Onat A, Hergenc G, Can G, Kaya Z, Yuksel H. Serum complement C3: a determinant of cardiometabolic risk, additive to the metabolic syndrome, in middle-aged population. Metabolism. 2010 May;59(5):628-34. doi: 10.1016/j.metabol.2009.09.006. Epub 2009 , Nov 14. PMID:19913840 doi:10.1016/j.metabol.2009.09.006
- ↑ Fremeaux-Bacchi V, Miller EC, Liszewski MK, Strain L, Blouin J, Brown AL, Moghal N, Kaplan BS, Weiss RA, Lhotta K, Kapur G, Mattoo T, Nivet H, Wong W, Gie S, Hurault de Ligny B, Fischbach M, Gupta R, Hauhart R, Meunier V, Loirat C, Dragon-Durey MA, Fridman WH, Janssen BJ, Goodship TH, Atkinson JP. Mutations in complement C3 predispose to development of atypical hemolytic uremic syndrome. Blood. 2008 Dec 15;112(13):4948-52. doi: 10.1182/blood-2008-01-133702. Epub 2008 , Sep 16. PMID:18796626 doi:10.1182/blood-2008-01-133702
- ↑ Maga TK, Nishimura CJ, Weaver AE, Frees KL, Smith RJ. Mutations in alternative pathway complement proteins in American patients with atypical hemolytic uremic syndrome. Hum Mutat. 2010 Jun;31(6):E1445-60. doi: 10.1002/humu.21256. PMID:20513133 doi:10.1002/humu.21256
- ↑ Onat A, Hergenc G, Can G, Kaya Z, Yuksel H. Serum complement C3: a determinant of cardiometabolic risk, additive to the metabolic syndrome, in middle-aged population. Metabolism. 2010 May;59(5):628-34. doi: 10.1016/j.metabol.2009.09.006. Epub 2009 , Nov 14. PMID:19913840 doi:10.1016/j.metabol.2009.09.006
- ↑ Baldo A, Sniderman AD, St-Luce S, Avramoglu RK, Maslowska M, Hoang B, Monge JC, Bell A, Mulay S, Cianflone K. The adipsin-acylation stimulating protein system and regulation of intracellular triglyceride synthesis. J Clin Invest. 1993 Sep;92(3):1543-7. PMID:8376604 doi:http://dx.doi.org/10.1172/JCI116733
- ↑ Cianflone KM, Sniderman AD, Walsh MJ, Vu HT, Gagnon J, Rodriguez MA. Purification and characterization of acylation stimulating protein. J Biol Chem. 1989 Jan 5;264(1):426-30. PMID:2909530
- ↑ Tao Y, Cianflone K, Sniderman AD, Colby-Germinario SP, Germinario RJ. Acylation-stimulating protein (ASP) regulates glucose transport in the rat L6 muscle cell line. Biochim Biophys Acta. 1997 Feb 18;1344(3):221-9. PMID:9059512
- ↑ Saleh J, Summers LK, Cianflone K, Fielding BA, Sniderman AD, Frayn KN. Coordinated release of acylation stimulating protein (ASP) and triacylglycerol clearance by human adipose tissue in vivo in the postprandial period. J Lipid Res. 1998 Apr;39(4):884-91. PMID:9555951
- ↑ Murray I, Kohl J, Cianflone K. Acylation-stimulating protein (ASP): structure-function determinants of cell surface binding and triacylglycerol synthetic activity. Biochem J. 1999 Aug 15;342 ( Pt 1):41-8. PMID:10432298
- ↑ Kalant D, MacLaren R, Cui W, Samanta R, Monk PN, Laporte SA, Cianflone K. C5L2 is a functional receptor for acylation-stimulating protein. J Biol Chem. 2005 Jun 24;280(25):23936-44. Epub 2005 Apr 14. PMID:15833747 doi:10.1074/jbc.M406921200
- ↑ Maslowska M, Legakis H, Assadi F, Cianflone K. Targeting the signaling pathway of acylation stimulating protein. J Lipid Res. 2006 Mar;47(3):643-52. Epub 2005 Dec 6. PMID:16333141 doi:10.1194/jlr.M500500-JLR200
- ↑ Cui W, Simaan M, Laporte S, Lodge R, Cianflone K. C5a- and ASP-mediated C5L2 activation, endocytosis and recycling are lost in S323I-C5L2 mutation. Mol Immunol. 2009 Sep;46(15):3086-98. Epub 2009 Jul 16. PMID:19615750 doi:S0161-5890(09)00421-0
- ↑ Baldo A, Sniderman AD, St-Luce S, Avramoglu RK, Maslowska M, Hoang B, Monge JC, Bell A, Mulay S, Cianflone K. The adipsin-acylation stimulating protein system and regulation of intracellular triglyceride synthesis. J Clin Invest. 1993 Sep;92(3):1543-7. PMID:8376604 doi:http://dx.doi.org/10.1172/JCI116733
- ↑ Cianflone KM, Sniderman AD, Walsh MJ, Vu HT, Gagnon J, Rodriguez MA. Purification and characterization of acylation stimulating protein. J Biol Chem. 1989 Jan 5;264(1):426-30. PMID:2909530
- ↑ Tao Y, Cianflone K, Sniderman AD, Colby-Germinario SP, Germinario RJ. Acylation-stimulating protein (ASP) regulates glucose transport in the rat L6 muscle cell line. Biochim Biophys Acta. 1997 Feb 18;1344(3):221-9. PMID:9059512
- ↑ Saleh J, Summers LK, Cianflone K, Fielding BA, Sniderman AD, Frayn KN. Coordinated release of acylation stimulating protein (ASP) and triacylglycerol clearance by human adipose tissue in vivo in the postprandial period. J Lipid Res. 1998 Apr;39(4):884-91. PMID:9555951
- ↑ Murray I, Kohl J, Cianflone K. Acylation-stimulating protein (ASP): structure-function determinants of cell surface binding and triacylglycerol synthetic activity. Biochem J. 1999 Aug 15;342 ( Pt 1):41-8. PMID:10432298
- ↑ Kalant D, MacLaren R, Cui W, Samanta R, Monk PN, Laporte SA, Cianflone K. C5L2 is a functional receptor for acylation-stimulating protein. J Biol Chem. 2005 Jun 24;280(25):23936-44. Epub 2005 Apr 14. PMID:15833747 doi:10.1074/jbc.M406921200
- ↑ Maslowska M, Legakis H, Assadi F, Cianflone K. Targeting the signaling pathway of acylation stimulating protein. J Lipid Res. 2006 Mar;47(3):643-52. Epub 2005 Dec 6. PMID:16333141 doi:10.1194/jlr.M500500-JLR200
- ↑ Cui W, Simaan M, Laporte S, Lodge R, Cianflone K. C5a- and ASP-mediated C5L2 activation, endocytosis and recycling are lost in S323I-C5L2 mutation. Mol Immunol. 2009 Sep;46(15):3086-98. Epub 2009 Jul 16. PMID:19615750 doi:S0161-5890(09)00421-0
- ↑ Baldo A, Sniderman AD, St-Luce S, Avramoglu RK, Maslowska M, Hoang B, Monge JC, Bell A, Mulay S, Cianflone K. The adipsin-acylation stimulating protein system and regulation of intracellular triglyceride synthesis. J Clin Invest. 1993 Sep;92(3):1543-7. PMID:8376604 doi:http://dx.doi.org/10.1172/JCI116733
- ↑ Cianflone KM, Sniderman AD, Walsh MJ, Vu HT, Gagnon J, Rodriguez MA. Purification and characterization of acylation stimulating protein. J Biol Chem. 1989 Jan 5;264(1):426-30. PMID:2909530
- ↑ Tao Y, Cianflone K, Sniderman AD, Colby-Germinario SP, Germinario RJ. Acylation-stimulating protein (ASP) regulates glucose transport in the rat L6 muscle cell line. Biochim Biophys Acta. 1997 Feb 18;1344(3):221-9. PMID:9059512
- ↑ Saleh J, Summers LK, Cianflone K, Fielding BA, Sniderman AD, Frayn KN. Coordinated release of acylation stimulating protein (ASP) and triacylglycerol clearance by human adipose tissue in vivo in the postprandial period. J Lipid Res. 1998 Apr;39(4):884-91. PMID:9555951
- ↑ Murray I, Kohl J, Cianflone K. Acylation-stimulating protein (ASP): structure-function determinants of cell surface binding and triacylglycerol synthetic activity. Biochem J. 1999 Aug 15;342 ( Pt 1):41-8. PMID:10432298
- ↑ Kalant D, MacLaren R, Cui W, Samanta R, Monk PN, Laporte SA, Cianflone K. C5L2 is a functional receptor for acylation-stimulating protein. J Biol Chem. 2005 Jun 24;280(25):23936-44. Epub 2005 Apr 14. PMID:15833747 doi:10.1074/jbc.M406921200
- ↑ Maslowska M, Legakis H, Assadi F, Cianflone K. Targeting the signaling pathway of acylation stimulating protein. J Lipid Res. 2006 Mar;47(3):643-52. Epub 2005 Dec 6. PMID:16333141 doi:10.1194/jlr.M500500-JLR200
- ↑ Cui W, Simaan M, Laporte S, Lodge R, Cianflone K. C5a- and ASP-mediated C5L2 activation, endocytosis and recycling are lost in S323I-C5L2 mutation. Mol Immunol. 2009 Sep;46(15):3086-98. Epub 2009 Jul 16. PMID:19615750 doi:S0161-5890(09)00421-0
- ↑ Xue X, Wu J, Ricklin D, Forneris F, Di Crescenzio P, Schmidt CQ, Granneman J, Sharp TH, Lambris JD, Gros P. Regulator-dependent mechanisms of C3b processing by factor I allow differentiation of immune responses. Nat Struct Mol Biol. 2017 Aug;24(8):643-651. doi: 10.1038/nsmb.3427. Epub 2017, Jul 3. PMID:28671664 doi:http://dx.doi.org/10.1038/nsmb.3427
|
