Distinct melanization pathways in the mosquito Aedes aegypti.
Serine protease cascades are involved in blood coagulation and immunity. In arthropods, they regulate melanization, which plays an important role in immune defense and wound healing. However, the mechanisms underlying melanization pathways are not completely characterized. We found that in the mosquito Aedes aegypti, there are two distinct melanization activation pathways carried out by different modules of serine proteases and their specific inhibitors serpins. Immune melanization proteases (IMP-1 and IMP-2) and Serpin-1 mediate hemolymph prophenoloxidase cleavage and immune response against the malaria parasite. Tissue melanization, exemplified by the formation of melanotic tumors, is controlled by tissue melanization protease (CLIPB8), IMP-1, and Serpin-2. In addition, serine proteases CLIPB5 and CLIPB29 are involved in activation of Toll pathway by fungal infection or by infection-independent manner, respectively. Serpin-2 is implicated in the latter activation of Toll pathway. This study revealed the complexity underlying melanization and Toll pathway in mosquitoes.
Department of Entomology and the Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA 92521, USA.
Zhen
Z
Zou
Sang Woon
SW
Shin
Kanwal S
KS
Alvarez
Vladimir
V
Kokoza
Alexander S
AS
Raikhel
D000330:Aedes / Q000276:immunology* / Q000378:metabolism; D000818:Animals; D007113:Immunity, Innate / Q000276:immunology*; D015151:Immunoblotting; D008543:Melanins / Q000276:immunology* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D057057:Serine Proteases / Q000276:immunology* / Q000378:metabolism; D015843:Serpins; D051193:Toll-Like Receptors / Q000276:immunology* / Q000378:metabolism; D020798:Two-Hybrid System Techniques
D008543:Melanins; D015843:Serpins; D051193:Toll-Like Receptors; D057057:Serine Proteases