Functions as a component of the nuclear pore complex (NPC) and the COPII coat. At the endoplasmic reticulum, SEC13 is involved in the biogenesis of COPII-coated vesicles. Required for the exit of adipsin (CFD/ADN), an adipocyte-secreted protein from the endoplasmic reticulum. As a component of the GATOR subcomplex GATOR2, functions within the amino acid-sensing branch of the TORC1 signaling pathway. Indirectly activates mTORC1 and the TORC1 signaling pathway through the inhibition of the GATOR1 subcomplex. It is negatively regulated by the upstream amino acid sensors SESN2 and CASTOR1. At the nuclear pore: component of the Y-shaped Nup107-160 subcomplex of the nuclear pore complex (NPC). The Nup107-160 subcomplex includes NUP160, NUP133, NUP107, NUP98, NUP85, NUP43, NUP37, SEH1 and SEC13. At the COPII coat complex: interacts with SEC31A and SEC31B. Within the GATOR complex, component of the GATOR2 subcomplex, made of MIOS, SEC13, SEH1L, WDR24 and WDR59. The GATOR complex strongly interacts with RRAGA/RRAGC and RRAGB/RRAGC heterodimers. The GATOR2 complex interacts with CASTOR2 and CASTOR1; the interaction is negatively regulated by arginine. The GATOR2 complex interacts with SESN1, SESN2 and SESN3; the interaction is negatively regulated by amino acids. Interacts with SEC16A. Interacts with SEC16B. In interphase, localizes at both sides of the NPC. Belongs to the WD repeat SEC13 family.