Interactome Analysis and Docking Sites of PCNA Subunits Reveal New Function in Arabidopsis thaliana

Proliferating Cell Nuclear Antigen (PCNA) is a protein known for its function in DNA replication in all eukaryotic cells. PCNA also has a role in DNA repair when exterior factors, like mutagenic UV-B radiation of sunlight, free radicals, ionizing radiations, chemical mutagens, etc., result in damage to DNA either genetoxically or cytotoxically. PCNA is usually of a toroidal shape and is made-up of either homo- or hetero-trimers. PCNA in Arabidopsis thaliana has two subunits; PCNA1 and PCNA2 that forms a homotrimeric structure. We found that the two subunits (PCNA1 and PCNA2) have a 97% similarity in their structures. Many studies have been conducted on PCNA from humans or yeast, but there is very little research done on plant PCNA. This study aims to close that gap, by conducting a study on PCNA subunits in Arabidopsis thaliana by predicting its 3D structure, domain analysis, subcellular localization, docking site prediction and PCNA interactome. Interactome analysis of PCNA revealed that it interacts with many proteins in DNA repair, such as Rad5, RAD9, RFC3, RFC5, RFC1, which are all a part of pathways involved in DNA repair. Interestingly we found that PCNA interacts with AtBRD1which is controlling shoot differentiation and meristem organization.