Ghai Rohit, Waters Patrick, Roumenina Lubka T, Gadjeva Mihaela, Kojouharova Mihaela S, Reid Kenneth B M, Sim Robert B, Kishore Uday
Institute of Medical Microbiology, Justus-Liebig-University, Frankfurter Strasse 107, 35392 Giessen, Germany.
Immunobiology. 2007;212(4-5):253-66. doi: 10.1016/j.imbio.2006.11.001. Epub 2006 Dec 12.
C1q is the target recognition protein of the classical complement pathway and a major connecting link between innate and acquired immunity. As a charge pattern recognition molecule of innate immunity, C1q can engage a broad range of self and non-self ligands via its heterotrimeric globular (gC1q) domain and thus trigger the classical pathway. The trimeric gC1q signature domain has been identified in a variety of non-complement proteins that can be grouped together as a C1q family. The X-ray crystal structures of the gC1q domain of a few members of the C1q family reveal a compact jelly-roll beta-sandwich fold similar to that of the multifunctional tumor necrosis factor (TNF) ligand family, hence the C1q and TNF superfamily. This review is an update on the structural and functional aspects of the gC1q domain of human C1q. We also mention the diverse range of proteins that utilize a gC1q domain in order to reflect on its importance as a versatile scaffold to support a variety of functions.
C1q是经典补体途径的靶标识别蛋白，也是固有免疫和获得性免疫之间的主要连接环节。作为固有免疫的一种电荷模式识别分子，C1q可通过其异源三聚体球状（gC1q）结构域与多种自身和非自身配体结合，从而触发经典途径。在多种非补体蛋白中已鉴定出三聚体gC1q特征结构域，这些蛋白可归为C1q家族。C1q家族一些成员的gC1q结构域的X射线晶体结构显示出一种紧凑的果冻卷β-三明治折叠，类似于多功能肿瘤坏死因子（TNF）配体家族，因此称为C1q和TNF超家族。本综述是关于人C1q的gC1q结构域的结构和功能方面的最新进展。我们还提及了利用gC1q结构域的多种蛋白质，以反映其作为支持多种功能的通用支架的重要性。
