The Role of SPATA5 and SPATA5L1 in Replisome Turnover
SPATA5 and SPATA5L1 are poorly characterized proteins belonging to the AAA+ ATPase superfamily. Our lab first identified SPATA5/5L1 as part of a four membered complex with likely cofactors C1ORF and CINP, all of which are required for complex stability and cell survival. SPATA5/5L1 were shown to be crucial for genome stability, cell cycle progression, and cell viability. SPATA5/5L1 show high sequence similarities to p97, a well characterized AAA+ ATPase. Prior research has shown that through unfoldase activity, p97 regulates protein dynamics and turnover at chromatin in DNA damage repair, DNA replication, and cell cycle progression. Prior work from our lab showed that the SPATA5/5L1 complex localizes to chromatin and interacts with replisome components. SPATA5/5L1 also mediate proteolytic cleavage of replisome components PolD3 and RFC1. Given these observations, SPATA5/5L1’s similarity to p97, and the importance of SPATA5/5L1 for cellular functioning, we wondered if the cleavage of PolD3 and RFC1 are processes through which SPATA5/5L1 regulate turnover of chromatin-associated replisome proteins. Using a Halo tag approach followed by pulse-chase experiments, we investigate SPATA5/5L1’s potential role in protein turnover and its larger role in DNA replication and genome stability.