Involved in microtubule formation, polymerization and assembly, regulating microtubule nucleation and length (PubMed:12956950, PubMed:12956951, PubMed:16054029). Plays a role in pronuclear migration and mitotic and meiotic spindle elongation during early embryogenesis (PubMed:12956950, PubMed:12956951). In complex with zyg-9, functions during the early stages of embryonic development to regulate microtubule assembly throughout the cell cycle (PubMed:12956950, PubMed:12956952). Specifically, the complex is required for the formation and growth of astral microtubules and spindle microtubules during mitotic spindle assembly (PubMed:12956952). At anaphase, the complex is required for mitotic spindle positioning in one-cell stage embryos (PubMed:17666432). The complex acts in a partially redundant manner with the tac-1/zyg-8 complex to regulate microtubule assembly and processes during interphase, mitosis and meiosis in embryos (PubMed:17666432). Plays a role in injury-induced axonal regrowth, regeneration and microtubule stability in PLM neurons and this may be downstream of efa-6 (PubMed:26339988). Interacts with zyg-9 to form a heterodimer (PubMed:12956950, PubMed:12956951, PubMed:12956952). Interacts with zyg-8 to form a heterodimer (PubMed:17666432). Interacts with efa-6 (via N-terminus) (PubMed:26339988). Initially enriched at meiotic spindle poles, but then recruited to the sperm centrosome (PubMed:12956950, PubMed:12956951). Localized to centrosomes early in pronuclear migration (PubMed:12956952). Centrosomal localization is dependent on air-1, tbg-1 and zyg-9 and is also controlled during the cell cycle, with high expression during prophase and metaphase, but with expression reducing from anaphase to telophase (PubMed:12956950, PubMed:12956951, PubMed:12956952). Accumulates at the centrosome during interphase, ready for the next mitotic cycle (PubMed:12956951). Cycles between cytoplasm and centrosome during mitosis in a cell cycle-dependent manner (PubMed:12956950, PubMed:17666432). Diffuse localization along the axon and localizes to perinuclear spots in the perikaryon (PubMed:26339988). Following injury co-localizes with efa-6 and ptrn-1 in puncta of the perikaryon (PubMed:26339988). The zyg-9/tac-1 complex localizes to centrosomes throughout the cell cycle and the kinetochore of metaphase and early anaphase chromosomes (PubMed:12956952). Expressed in touch neurons. Maternal-effect embryonic lethal (PubMed:23155404). RNAi-mediated knockdown results in a meiotic defect in 30% of early embryos and defective microtubule related processes during the first cell cycle in early embryogenesis (PubMed:12956950, PubMed:12956951, PubMed:12956952). In one-cell embryos, the maternal pronuclei fail to migrate and the breakdown of the pronuclear envelope is delayed (PubMed:12956950, PubMed:12956951, PubMed:12956952). The sperm pronuclear complex also exhibits a migratory defect whereby it does not move to the center of the embryo or rotate on the anterior-posterior axis leading to the assembly of a misaligned spindle at the posterior of the embryo and ingression of the cleavage furrow from the posterior cortex (PubMed:12956950, PubMed:12956951, PubMed:12956952, PubMed:17666432). Reduced microtubule growth rate in embryos (PubMed:16054029). Defective microtubule elongation in one-cell embryos resulting in short microtubules that extend from the centrosome, but do not extend to the cortex, and mitotic spindles that are 20% shorter than in wild-type one-cell embryos (PubMed:12956950, PubMed:12956951). Specifically, one-cell embryos have shorter astral and mitotic spindle microtubules (PubMed:12956952). Reduced stability of the zyg-9/tac-1 complex with reduced accumulation of zyg-9 at the centrosomes (PubMed:12956950). Belongs to the TACC family.