Dynamin (dyn-1) functions via calcineurin, a Ca2+/calmodulin dependent Ser/Thr protein phosphatase, in endocytosis

Abstract

C. elegans has been an ideal model organism to reveal the in vivo mechanism of clathrin-mediated endocytosis. One major clathrin-mediated endocytosis in C. elegans is using coelomocytes, 6 macrophage-like scavenger cells, to endocytose foreign molecules from body cavity. Dynamin, a large GTPase protein, is involved in clathrin-mediated endocytosis. Here, we report a possible function of calcineurin, a Ca2+/calmodulin-dependent Ser/Thr protein phosphatase, in C. elegans coelomocyte endocytosis using previously reported in vivo monitoring assay systems. We observe that calcineurin A gain of function tax-6(jh107) and calcineurin B null cnb-1(jh103) mutants display 20% and 60% of defective endocytosis in coelomocytes, respectively. Calcineurin probably regulates coelomocyte endocytosis by dephosphorylating DYN-1. Epistatic analysis proposes that CUP-5, nicotinic acetylcholine receptor homolog, may functionally act in the downstream of this pathway.