Cloning and characterization of a possible adhesion molecule expressed by hepatic non-parenchymal cells

点击翻译按钮获取中文摘要

Cells change their phenotype and functions in response to the specificity of the extracellular matrix. We now report the cloning and characterization of a cDNA encoding a new member of the protein-kinase family, which can be involved in the cell-matrix interaction. The expression cDNA library obtained from a fat-storing cell (FSC) line was screened with an antibody prepared against a plasma membrane fraction of rat hepatocytes, which was supposed to contain the matrix receptor. The antibody reacted with a protein localized on the sinusoidal domain of hepatocytes. It also recognized various proteins synthesized by FSC.From 1.5x10^5 phages, 11 clones were isolated. Ten of the 11 clones derived from the same mRNA corresponding an unkown protein. Finally, we dtermined the nucleotide sequence of 6456bp. The predicted protein of this clone had two copies of serine/threonine protein-kinase domains in N-terminal end, which showed less than 40% homology with catalytic domains of previously reported protein kinases. In the C-terminus, it contained a leucine zipper domain. The cDNA recognized a 7kb mRNA in freshly isolated and cultured FSC,endothelial and Kupffer cells. In contrast, this mRNA was not detected in hepatocytes. The expression of this mRNA appeared to decrease in cultured FSC.The function of the cloned cDNA is currently under investigation.