The present invention relates generally to a newly identified adaptor protein FRS2 and related products and methods. FRS2 links protein kinases to activating partners in cells. The invention also relates to nucleic acid molecules encoding portions of FRS2, nucleic acid vectors containing FRS2 related nucleic acid molecules, recombinant cells containing such nucleic acid vectors, polypeptides purified from such recombinant cells, antibodies to such polypeptides, and methods of identifying compounds that enhance or block FRS2 interactions with natural binding partners. Also disclosed are methods for diagnosing abnormal conditions in an organism with FRS2 related molecules or compounds.