The CLIP-Domain Serine Protease Homolog SPCLIP1 Regulates Complement Recruitment to Microbial Surfaces in the Malaria Mosquito Anopheles gambiae

The complement c3-like protein tep1 of the mosquito anopheles gambiae is required for defense against malaria parasites and bacteria. two forms of tep1 are present in the mosquito hemolymph,the full-length tep1-f and the proteolytically processed tep1cut that is part of a complex including the leucine-rich repeat proteins lrim1 and apl1c. here we show that the non-catalytic serine protease spclip1 is a key regulator of the complement-like pathway. spclip1 is required for accumulation of tep1 on microbial surfaces,a reaction that leads to lysis of malaria parasites or triggers activation of a cascade culminating with melanization of malaria parasites and bacteria. we also demonstrate that the two forms of tep1 have distinct roles in the complement-like pathway and provide the first evidence for a complement convertase-like cascade in insects analogous to that in vertebrates. our findings establish that core principles of complement activation are conserved throughout the evolution of animals. © 2013 povelones et al.