Factor I cleaves iC3b

Stable Identifier
Reaction [transition]
Homo sapiens
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Factor I (CFI) cleaves iC3b into two molecules, C3c, which is released into solution, and C3dg, which remains attached to the membrane. This cleavage requires Complement receptor type 1 (CR1), which serves a cofactor for CFI (Medof et al. 1982). iC3b and C3dg can bind CR2 (CD21) to enhance B-cell immunity (Tuveson et al.1991, Sarrias et al. 2001).

Literature References
PubMed ID Title Journal Year
2971659 Identification of the C3b receptor-binding domain in third component of complement

Lambris, JD, Becherer, JD

J. Biol. Chem. 1988
6607952 Physiologic inactivation of fluid phase C3b: isolation and structural analysis of C3c, C3d,g (alpha 2D), and C3g

Harrison, RA, Davis, AE, Lachmann, PJ

J. Immunol. 1984
21788512 Unique structure of iC3b resolved at a resolution of 24 Å by 3D-electron microscopy

de Córdoba, SR, Fernández, FJ, Round, A, Alcorlo, M, Martínez-Barricarte, R, Llorca, O, Harris, CL, Vega, MC, Rodríguez-Gallego, C

Proc. Natl. Acad. Sci. U.S.A. 2011
Catalyst Activity

serine-type endopeptidase activity of CFI [extracellular region]

Orthologous Events
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