CRK is a member of signaling adapter protein family that binds to several tyrosine-phosphorylated proteins. This protein is involved in many cellular processes including apoptosis, proliferation, and differentiation. It has a modular domain architecture consisting of an SH2 followed by two SH3 domains (src-homology domains). The N-terminal SH2 domain of this protein functions as a positive regulator of transformation whereas the C-terminal SH3 domain functions as a negative regulator of transformation. Recombinant human CRK protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography. Synonyms: Adapter molecule crk, Proto-oncogene c-Crk, p38, CRKII. NCBI no.: NP_005197