The function of SIMC1 (SUMO interacting motifs containing 1, ENSG00000170085) is as follows. Plays a role in SMC5-SMC6 complex recruitment for viral restriction. Forms a complex with SLF2 and this complex is required to recruit SMC5-SMC6 complex to PML nuclear bodies and sites of viral replication. . [Isoform 1]: Inhibits the protease activity of CAPN3. . [Isoform 5]: Inhibits the protease activity of CAPN3. .