User:Matthew Chien/Sandbox 1: Difference between revisions

'''Complement component 1q''', or <scene name='10/1078778/C1q_globular_head/1'>C1q</scene>, is the first component of the classical pathway of the complement system. C1q is a subcomponent of the Complement component 1 (C1), along with C1r and C1s. C1q consists of six globular-head regions all connected to a collagen-like region (<scene name='10/1078778/Collagen-like_region_of_c1q/4'>CLR</scene>), with each globular head consisting of 3 separate <scene name='10/1078778/Domains/4'>domains</scene>, having a total mass of roughly 460 kDa. The globular heads entirely consist of β-sheets. The activation of C1q through the binding of the globular head to a variety of epitopes induces structural changes in the collagen-like region of C1q. This activates C1r, which cleaves C1s, which splits into other complement proteins to further activate other aspects of the classical complement system pathway. C1q binds to a variety of different antigens, such as phagocytes to induce phagocytosis, apoptotic cells through phosphatidylserine and DNA to induce apoptosis, and the Fc region of IgG and IgM to activate the complement system as described. C1q acts as a crucial protein that bridges the adaptive and innate immune system. <ref>PMID:29692784</ref><ref>Janeway CA Jr, Travers P, Walport M, et al. Immunobiology: The Immune System in Health and Disease. 5th edition. New York: Garland Science; 2001. The complement system and innate immunity. Available from: https://www.ncbi.nlm.nih.gov/books/NBK27100/</ref>