Brk: Proteins and Enzymes

Brk is an intracellular non-receptor tyrosine kinase. It was first identified in human breast tumor cell lines, is frequently overexpressed in primary breast tumors, and is absent from normal breast tissue. Other sites of expression include colon, small intestine and prostate. Brk contains one SH3 domain, one SH2 domain, and a Tyr-kinase catalytic domain.