IDENTIFICATION OF TYROSINE-PHOSPHORYLATED ADHESION PROTEINS IN HUMAN CANCER-CELLS

Tyrosine phosphorylation is a form of signal transduction that regulat es cell growth, differentiation, migration, and survival. This knowled ge has promoted much interest in the role of tyrosine kinases and phos phatases in regulating cell behavior during development and tumorigene sis. However, it is generally less well appreciated that tyrosine phos phorylated proteins are enriched within sites of cell adhesion, partic ularly in transformed cells. To identify these, we developed a panel o f monoclonal antibodies specific for tyrosine phosphorylated proteins in breast cancer cells, using extensive modifications of existing tech nologies for immunization, somatic fusion, and antibody screening. Mic e were immunized with a complex mixture of phosphotyrosine containing proteins using the newly developed RIMMS method. By increasing the sen sitivity of antigen recognition, we isolated reagents specific for a w ide diversity of tyrosine phosphorylated adhesion proteins in breast c ancer cells.