Functions as a component of the nuclear pore complex (NPC) and the COPII coat (By similarity). Required for the nuclear import of hcp-4 during mitotic prophase, this step is essential for centrosome assembly and resolution (PubMed:28122936). As a component of the GATOR complex may function in the amino acid-sensing branch of the TORC1 signaling pathway. Component of a heterotertrameric COPII coat complex composed of npp-20 and sec-31 (Probable). Probably part of the GATOR complex. Localizes close to endoplasmic reticulum exit sites (ERES) and the nuclear envelopes of proliferating germ nuclei. RNAi-mediated knockdown results in embryonic lethality (PubMed:12937276, PubMed:28122936). Causes severe defects in mitosis (PubMed:28122936). Cytokinesis is blocked and nucleus formation is impaired after the first embryonic mitosis (PubMed:12937276). Centrosome assembly during prophase and prometaphase and their subsequent resolution are impaired which results from impaired nuclear import of hcp-4 (PubMed:28122936). Impaired sister chromatin segregation (PubMed:28122936). Belongs to the WD repeat SEC13 family.