Ca2+/calmodulin-dependent phosphorylation of endocytic scaffold ITSN1

Abstract

ITSN1 is an endocytic scaffold protein with a prominent function in synaptic transmission. It is known that Ca2+ signaling is crucial for the regulation of synaptic proteins functioning. Aim. Checking the possibility of Ca2+/calmodulin-dependent phosphorylation of ITSN1. Methods. Affinity chromatography, in vitro kinase reaction, Western blotting, gel staining with fluorescent stains. Results. We show that the fraction of calmodulin- binding proteins is able to phosphorylate the recombinant fragments encoding the coiled-coil region and the SH3 domain-containing region of ITSN1 in the presence of Ca2+ ions and calmodulin. Conclusions. The coiledcoil region and the SH3 domain-containing region of ITSN1 undergo Ca2+/calmodulin-dependent phosphorylation in vitro, suggesting a possible regulation of ITSN1 by Ca signaling.