BRPK, a novel protein kinase showing increased expression in mouse cancer cell lines with higher metastatic potential.

A novel protein kinase named BRPK was isolated and partially characterized. BRPK was expressed at a higher level in three carcinoma cell lines with higher metastatic potential. Mouse and human BRPK cDNAs are well conserved and encode 580 and 581 amino acids, respectively. BRPK has a serine/threonine-type protein kinase domain, and the recombinant proteins of BRPK were capable of autophosphorylation. The results of a comparative sequence analysis indicated a possible link of BRPK to BRAP2. BRAP2 is known to bind the nuclear localization signal of BRCA1. We cloned mouse BRAP2 cDNA and showed the presence of isoforms.