Transformation of normal rat kidney cells by v-K-ras enhances expression of transin 2 and an S-100-related calcium-binding protein

Abstract

v-K-ras transformants of normal rat kidney cells (KNRK) exhibit cell surface-related, transformation-specific properties, including cell-surface fibronectin depletion, induction of anchorage- and density-independent growth, and increased synthesis of transforming growth factors alpha and beta. To search for potential distal effectors of v-K-ras-mediated transformation, we prepared a rabbit antiserum directed against intact KNRK cells to immunoprecipitate and compare proteins from detergent lysates and conditioned media of labeled NRK, KNRK, B77-NRK (a v-src transformant) and ts-371-NRK cells (a Ki-MSV encoding a temperature-sensitive p21v-K-ras). Proteins with enhanced expression in both wild-type v-K-ras and v-src transformants included a cell-surface phosphoglycoprotein with apparent Mr of 79,000 (79K) modified from an 85K protein observed in NRK cell lysates, a cytoplasmic 47K and a 10K protein, and a 57K secreted glycoprotein. A KNRK-specific 21K membrane-associated protein and secreted 59K and 36K secreted glycoproteins were also detected. The expression of the 36K and 59K proteins best correlated with temperature-dependent activation of the ts-371-NRK p21v-K-ras. Immunoselection of recombinant clones from a KNRK-specific lambda gt11 cDNA library allowed identification of the 59K and 10K proteins as transin 2 and an S-100-related calcium-binding protein identified as p9Ka/42A but not previously associated with oncogenic transformation of rat cells. Transin 2 detection by a cell-derived antiserum may also suggest the presence of specific cell-surface binding sites for this enzyme.