Replication Protein A4 (RPA4)

Replication protein A (RPA) is single-stranded DNA (ssDNA)-binding complex essential for cell viability and chromosome stability. The canonical RPA complex contains RPA1, RPA2, and RPA3. However, RPA4 can substitute for RPA2 to form an alternative RPA complex.The deduced 261-amino acid protein has a calculated molecular mass of 28.9 kD. RPA4 shares 47% amino acid identity with RPA2, and both proteins have glycine- and serine-rich N-terminal sequences. Western blot analysis detected RPA4 as a 30-kD protein with strong expression in human placenta and low expression in colon. RPA4 expression was also detected in neuroblastoma, colon carcinoma, and Ewing sarcoma cell lines.