Human complement factor H-related protein 4 binds and recruits native pentameric C-reactive protein to necrotic cells

Monomeric CRP contributes to complement control in fluid phase and on cellular surfaces and increases phagocytosis by recruiting factor H

“…However, CFHR4A, an additional Factor H family protein, binds pCRP but not mCRP. 25 CRP contacts Factor H at three sites. In addition to the two previously identified sites in SCR 7 and SCRs 8-11, a novel third C-terminal-binding region was identified (Figure 1a-e and 2b).…”

Factor H-related Protein 4 Activates Complement by Serving as a Platform for the Assembly of Alternative Pathway C3 Convertase via Its Interaction with C3b Protein

“…Recently, we described native pentameric C-reactive protein (CRP) as a ligand for CFHR4A and CFHR4B, and we showed that this interaction via a binding site in SCR1 leads to enhanced opsonization of necrotic cells with CRP and promotes complement activation via C4-dependent pathways (11,12).…”

Monomeric C-reactive protein inhibits renal cell-directed complement activation mediated by properdin

“…For endothelial progenitor cells, mCRP induced a proinflammatory response in particular in interferonresponsive genes, with pCRP exhibiting no such response (2). With regard to complement, complement factor H-related protein 4 binds pCRP but not mCRP (27). Furthermore, mCRP has been shown to interact with other complement proteins, including C4bp, FH, and FHL-1 protein, indicating its diverse role in the complement system (5,26,28).…”

“…Previous studies have demonstrated that CRP, both pCRP and mCRP, can interact with various complement proteins (5,27,28). To investigate whether pCRP or mCRP can interact with properdin in solution, we used an ELISA system.…”