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 (PubMed:8972206). Required for the exit of adipsin (CFD/ADN), an adipocyte-secreted protein from the endoplasmic reticulum (By similarity). 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 (PubMed:23723238). It is negatively regulated by the upstream amino acid sensors SESN2 and CASTOR1 (PubMed:25457612, PubMed:27487210). 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 (PubMed:14517296, PubMed:16495487, PubMed:16957052, PubMed:18160040, PubMed:23723238). The GATOR2 complex interacts with CASTOR2 and CASTOR1; the interaction is negatively regulated by arginine (PubMed:26972053). The GATOR2 complex interacts with SESN1, SESN2 and SESN3; the interaction is negatively regulated by amino acids (PubMed:25263562, PubMed:25457612). Interacts with SEC16A (PubMed:17428803, PubMed:19638414, PubMed:25201882). Interacts with SEC16B (PubMed:22355596). In interphase, localizes at both sides of the NPC. Belongs to the WD repeat SEC13 family.