Biopolym. Cell. 2015; 31(5):338-344.
Structure and Function of Biopolymers
Identification of Ca2+/calmodulin-dependent phosphorylation sites of endocytic scaffold ITSN1 by tandem mass spectrometry
1Morderer D. Ye., 2Nikolaienko O. V., 1Rynditch A. V.
  1. Institute of Molecular Biology and Genetics, NAS of Ukraine
    150, Akademika Zabolotnoho Str., Kyiv, Ukraine, 03680
  2. Department of Biomedicine, University of Bergen
    91, Jonas Lies vei, Bergen, Norway, 5009


ITSN1 is a scaffold protein involved in endocytosis, signal transduction and cytoskeleton regulation. It has been previously shown that ITSN1 undergoes Ca2+/calmodulin-dependent phosphorylation in vitro. Aim. We intend to identify these phosphorylation sites. Methods. In vitro kinase reaction; liquid chromatography-tandem mass spectrometry (LC/MS/MS). Results. We identified five sites of Ca2+/calmodulin-dependent phosphorylation in the recombinant fragments of ITSN1. Conclusions. We have shown that the ITSN1 coiled-coil region (CCR) and the interdomain linkers between EH2 and CCR, SH3A and SH3B, SH3B and SH3C domains were phosphorylated in a Ca2+/calmodulin-dependent manner in vitro.
Keywords: ITSN1, Ca2+, phosphorylation, LC/MS/MS


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