This gene is a protooncogene that encodes a protein tyrosine kinase involved in a variety of cellular processes| including cell division| adhesion| differentiation| and response to stress. The activity of the protein is negatively regulated by its SH3 domain| whereby deletion of the region encoding this domain results in an oncogene. The ubiquitously expressed protein has DNA-binding activity that is regulated by CDC2-mediated phosphorylation| suggesting a cell cycle function. This gene has been found fused to a variety of translocation partner genes in various leukemias| most notably the t(9;22) translocation that results in a fusion with the 5' end of the breakpoint cluster region gene (BCR; MIM:151410). Alternative splicing of this gene results in two transcript variants| which contain alternative first exons that are spliced to the remaining common exons.