Identification of the interacting proteins of hHBRK1, an over-expressed gene in the α particles-transformed human bronchial epithelial cells

抄録

HHBrk1, human homology of maize Brick1 gene, was primarily identified to be an over-expressed novel gene in the α particles-transformed human bronchial epithelial cells in our laboratory. While maize Brike1 gene functions in promoting polarified cell division and cell morphogenesis in the maize leaf epidermis. HHBrk1 is predominantly expressed in the heart and skeletal muscle. The vector encoding GFP-hHBRK1 fusion protein was constructed and transfected the 95D lung cancer cells. GFP-hHBRK1 fusion protein was found to specifically recruited to the actomyosin ring and the tips of lamellipodia in cultured 95D cells, indicating that the gene product is a filament actin related protein and might be involved in actin filament assembly. To gain more information for elucidation the detail function of hHBRK1, the interacting protein of hHBRK1 was identified in heart tissues of mouse by GST pull-down assay and peptide mass fingerprint. The interaction between hHBRK1 and Ea isoform of cardiac troponin T (cTnT) was unveiled and further confirmed by coimmunoprecipitation and western blot analysis. Ea isoform is the result of alternative splicing in the N-terminal region of cTnT. These findings suggest that hHBRK1-cTnT interaction might function in the actin cytoskeletal organization