Biopolym. Cell. 2011; 27(4):306-309.
Short Communications
Novel isoform of adaptor protein ITSN1 forms homodimers via its C-terminus
1Dergai M. V., 1Dergai O. V., 1Tsyba L. O., 1Novokhatska O. V., 1Skrypkina I. Ya., 1Rynditch A. V.
  1. Institute of Molecular Biology and Genetics, NAS of Ukraine
    150, Akademika Zabolotnoho Str., Kyiv, Ukraine, 03680


Aim. Previously we have identified a novel isoform of endocytic adaptor protein ITSN1 designated as ITSN1- 22a. Western blot revealed two immunoreactive bands of 120 and 250 kDa that corresponded to ITSN1-22a. The goal of this study was to investigate the possibility of dimer formation by the novel isoform. Methods. Dimerization ability of ITSN1-22a was tested by immunoprecipitation and subsequent Western blot analysis. To specify the region responsible for dimerization, site-directed mutagenesis and truncation analysis were carried out. Inhibition of endocytosis by potassium depletion and EGF stimulation of HEK293 were performed. Results. We have found that ITSN1-22a forms dimers in HEK293 cells. The dimerization of ITSN1-22a was mediated by C-terminal domain. We showed that cysteines C1016 and C1019 were involved in homodimerization. Inhibition of clathrin-mediated endocytosis and mitogen stimulation did not affect ITSN1-22a dimer formation. Conclusions. ITSN1-22a is the only one known ITSN1 isoform, which is capable to form homodimers via disulphide bonds. This could be important for the formation of protein complexes containing ITSN1 molecules.
Keywords: intersectin 1, isoform, homodimer


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