Ubiquitin-conjugating enzyme E2 (PubMed:19553937). Accepts ubiquitin from the E1 complex and catalyzes its covalent attachment to other proteins (PubMed:19553937). Required for diet restriction-mediated lifespan extension, probably acting as part of a complex with ubiquitin-protein ligase wwp-1 (PubMed:19553937). Acts redundantly with lin-35/Rb in the regulation of pharyngeal morphogenesis during embryonic development by negatively regulating the expression of proteins such as sup-35 (PubMed:12783801, PubMed:19521497). S-ubiquitinyl-[E1 ubiquitin-activating enzyme]-L-cysteine + [E2 ubiquitin-conjugating enzyme]-L-cysteine = [E1 ubiquitin-activating enzyme]-L-cysteine + S-ubiquitinyl-[E2 ubiquitin-conjugating enzyme]-L-cysteine. Interacts with E3 ubiquitin-protein ligase wwp-1 (PubMed:19553937). Interacts with RBR-type E3 ubiquitin transferase ari-1.1 (PubMed:16457801). Expressed in neurons localized in the head and tail of adults. RNAi-mediated knockdown very slightly reduces viability and brood size; phenotype is exacerbated on a mutant background which enhances the overall efficacy of RNAi (PubMed:12783801). Increases sensitivity to paraquat and reduces lifespan at 25 degrees Celsius, but not at 20 degrees Celsius (PubMed:19553937). Abolishes lifespan extension completely on an eat-2 mutant background (PubMed:19553937). Substantially increases embryonic expression of sup-35 (PubMed:19521497). Belongs to the ubiquitin-conjugating enzyme family.