Forms a fork protection complex (FPC) with TOF1 and which is required for chromosome segregation during meiosis and DNA damage repair. FPC coordinates leading and lagging strand synthesis and moves with the replication fork. FPC stabilizes replication forks in a configuration that is recognized by replication checkpoint sensors (By similarity). Component of the fork protection complex (FPC) consisting of TOF1 and CSM3. Belongs to the CSM3 family.