Forms a fork protection complex (FPC) with swi3. FPC coordinates leading and lagging strand synthesis and moves with the replication fork. It is required for programmed fork-pausing which is necessary for mating-type switching. FPC stabilizes replication forks in a configuration that is recognized by replication checkpoint sensors. It is involved in termination at the mat1-proximal polar-terminator of replication (RTS1) and also required for activation of the Rad53-like checkpoint kinase cds1. Fork protection complex (FPC) consisting of swi1 and swi3 interacts with mat1 cis-acting sequences and mat1-proximal polar-terminator of replication (RTS1). Associated with chromatin during S phase. Nuclear accumulation requires swi3.