Functions as a component of the nuclear pore complex (NPC) and the COPII coat (By similarity). At the endoplasmic reticulum, SEC13 is involved in the biogenesis of COPII-coated vesicles (By similarity). Recruited to transcriptionally active chromatin at the time of transcription initiation by RNA polymerase II (PubMed:20144761). Required for proper expression of ecdysone-responsive genes such as Eip74EF and Eip75B during larval development (PubMed:20144761). Required for reactivation of transcription after heat shock (PubMed:20144761). Required for nuclear import of phosphorylated Mad via importin msk (PubMed:20547758). Has no role in classical nuclear localization signal (cNLS)-dependent nuclear import via importin-beta (PubMed:20547758). A component of the GATOR subcomplex GATOR2 which functions as an activator of the amino acid-sensing branch of the TORC1 signaling pathway (PubMed:27166823). The two GATOR subcomplexes, GATOR1 and GATOR2, regulate the TORC1 pathway in order to mediate metabolic homeostasis, female gametogenesis and the response to amino acid limitation and complete starvation (PubMed:27166823). GATOR2 activates the TORC1 signaling pathway through the inhibition of the GATOR1 subcomplex, controlling the switch to cell proliferation and growth under nutrient replete conditions and during female oocyte development (PubMed:27166823). Probable component of the nuclear pore complex (NPC) (By similarity). Component of the GATOR complex consisting of mio, Nup44A/Seh1, Im11, Nplr3, Nplr2, Wdr24, Wdr59 and Sec13 (PubMed:27166823). Within the GATOR complex, probable component of the GATOR2 subcomplex which is likely composed of mio, Nup44A/Seh1, Wdr24, Wdr59 and Sec13 (PubMed:27166823). Interacts with msk (PubMed:20547758). Interacts (preferentially when phosphorylated) with Mad (PubMed:20547758). Localizes to chromatin, specifically to areas undergoing transcriptional activation. Chromatin localization is independent of the nuclear pore complex (PubMed:20144761). Salivary glands. Expressed during larval development. RNAi-mediated knockdown in the larva results in reduced transcription of developmental genes Eip74EF and Eip75B in the salivary glands, compromised transcriptional recovery after heat shock and defective recruitment of Nup98. Belongs to the WD repeat SEC13 family. Extended N-terminus.