Csk-homologous kinase interacts with SHPS-1 and enhances neurite outgrowth of PC12 cells.

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.
Mesh Terms:
Animals, Bacterial Proteins, Cells, Cultured, Cercopithecus aethiops, Cerebral Cortex, Cloning, Molecular, Embryo, Mammalian, Gene Expression, Glutathione Transferase, Humans, Luminescent Proteins, Mutation, Neurites, Neurons, PC12 Cells, Phosphorylation, Proto-Oncogene Proteins pp60(c-src), Rats, Receptors, Immunologic, Transfection, Two-Hybrid System Techniques, Tyrosine, src Homology Domains
J. Neurochem.
Date: Apr. 01, 2008
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