A ZYXIN-RELATED PROTEIN WHOSE SYNTHESIS IS REDUCED IN VIRALLY TRANSFORMED FIBROBLASTS

We have cloned the gene for a novel LIM-domain protein from human fibr oblasts whose expression is substantially decreased in simian-virus-40 -(SV4O)-transformed cells. This protein has a calculated molecular mas s of 61 kDa and comprises a proline-rich domain followed by three LIM motifs. It appears to be identical to the focal adhesion protein p83 t hat has recently been isolated and characterized from porcine and huma n platelets. Hybridization experiments demonstrate a very low degree o f evolutionary conservation of its sequence between mammals and birds. It is therefore possible that the novel protein represents the human equivalent of the chicken protein zyxin as the two proteins display a very similar overall structure, although their amino acid sequences di verge markedly from each other. The repression of this zyxin-related p rotein in virally transformed fibroblasts may explain, at least in par t, the dramatic morphological changes that occur at the cell surface a nd in the cytoskeleton of transformed cells.