Component of the eukaryotic translation initiation factor 3 (eIF-3) complex, which is involved in protein synthesis of a specialized repertoire of mRNAs and, together with other initiation factors, stimulates binding of mRNA and methionyl-tRNAi to the 40S ribosome. The eIF-3 complex specifically targets and initiates translation of a subset of mRNAs involved in cell proliferation (Potential). Component of the COP9 signalosome complex (CSN), a complex involved in various cellular and developmental processes (PubMed:17403899). The CSN complex is an essential regulator of the ubiquitin (Ubl) conjugation pathway by mediating the deneddylation of the cullin subunits of the SCF-type E3 ligase complexes, leading to decrease the Ubl ligase activity of SCF (PubMed:17403899). The CSN complex plays an essential role in embryogenesis and oogenesis and is required to regulate microtubule stability in the early embryo. Mediates mei-1 targeting for degradation at the meiosis to mitosis transition via deneddylation of cul-3 (PubMed:17403899). Component of the eukaryotic translation initiation factor 3 (eIF-3) complex. Within the eIF-3 complex, interacts directly with eif-3.F. Component of the CSN complex, composed of csn-1, csn-2, csn-3, csn-4, csn-5, csn-6 and csn-7. Within the CSN complex, interacts directly with csn-1 and csn-4. Belongs to the eIF-3 subunit M family.