PCNAs

PCNA is a protein that functions as a homotrimer and is found in the nucleus of eukaryotic cells. It is also known as cyclin-dependent cell proliferation nuclear antigen. PCNA is a highly conserved protein, meaning its structure is similar across different species. Its primary role is as a processivity factor for DNA polymerase delta and epsilon. In simpler terms, PCNA helps these enzymes to synthesize DNA more efficiently and for longer stretches. This is crucial for DNA replication, a fundamental process for cell division.

Beyond its role in replication, PCNA is also involved in DNA repair pathways. It acts as a scaffold, recruiting other proteins to sites of DNA damage to facilitate repair. This dual function highlights its importance in maintaining genomic integrity. The expression of PCNA is tightly regulated and generally correlates with cell proliferation. Therefore, PCNA is often used as a marker for actively dividing cells in research and diagnostic settings. Its interaction with various proteins makes it a key player in coordinating DNA replication and repair, ensuring accurate duplication of genetic material during cell division and in response to cellular damage.