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Csk‐homologous kinase interacts with SHPS‐1 and enhances neurite outgrowth of PC12 cells
Author(s) -
Mitsuhashi Hiroaki,
Futai Eugene,
Sasagawa Noboru,
Hayashi Yukiko,
Nishino Ichizo,
Ishiura Shoichi
Publication year - 2008
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2007.05121.x
Subject(s) - protein tyrosine phosphatase , proto oncogene tyrosine protein kinase src , microbiology and biotechnology , tyrosine phosphorylation , phosphorylation , biology , neurite , tyrosine , tyrosine kinase , receptor tyrosine kinase , sh2 domain , sh3 domain , signal transduction , biochemistry , in vitro
SHPS‐1 is an immunoglobulin superfamily protein with four immunoreceptor tyrosine‐based inhibitory motifs (ITIMs) in its cytoplasmic region. Various neurotrophic factors induce the tyrosine phosphorylation of SHPS‐1 and the association of SHPS‐1 with the protein tyrosine phosphatase SHP‐2. Using a yeast two‐hybrid screen, we identified a protein tyrosine kinase, Csk‐homologous kinase (CHK), as an SHPS‐1‐interacting protein. Immunoprecipitation and pull‐down assays using glutathione S ‐transferase (GST) fusion proteins containing the Src homology 2 (SH2) domain of CHK revealed that CHK associates with tyrosine‐phosphorylated SHPS‐1 via its SH2 domain. HIS3 assay in a yeast two‐hybrid system using the tyrosine‐to‐phenylalanine mutants of SHPS‐1 indicated that the first and second ITIMs of SHPS‐1 are required to bind CHK. Over‐expression of wild‐type CHK, but not a kinase‐inactive CHK mutant, enhanced the phosphorylation of SHPS‐1 and its subsequent association with SHP‐2. CHK phosphorylated each of four tyrosines in the cytoplasmic region of SHPS‐1 in vitro . Co‐expression of SHPS‐1 and CHK enhanced neurite outgrowth in PC12 cells. Thus, CHK phosphorylates and associates with SHPS‐1 and is involved in neural differentiation via SHP‐2 activation.