c-Abl (Abelson murine leukemia viral homolog 1) is a cytosolic member of the ABL subfamily, protein tyrosine kinase family of enzymes. It is ubiquitously expressed, and participates in multiple processes such as cell migration, actin reorganization, DNA damage response and apoptosis. Human c-Abl (I-B) is 1149 amino acids (aa) in length. It is myristoylated on Gly2 and contains one SH3 domain (aa 80-140), an SH2 domain (aa 146-236), a protein kinase region (aa 261-512), three NLS's (aa 620-634; 726-739; 778-791), one DNA-binding region (aa 888-988), an NES motif (aa 1109-1119) and an actin F-binding domain (aa 1120-1149). There is one alternate splice form (I-A) that contains a 26 aa substitution for the N-terminal 45 amino acids. In chronic myelogenous leukemia, c-Abl is fused to the Bcr gene product, resulting in the production of a constitutively active tyrosine kinase.