Regulates mitotic spindle assembly, microtubule (MT)-kinetochore attachment and chromosome separation via recruitment of HAUS augmin-like complex and TUBG1 to the existing MTs and promoting MT-based MT nucleation (By similarity). Required for proper alignnment of chromosomes during metaphase (By similarity). Homotrimer; self-association is mediated by the N-terminal coiled coil (By similarity). Interacts with EML2 but not with EML1 (By similarity). Interacts (phosphorylated at Thr-882) with TUBG1, HAUS1, HAUS2, HAUS3, HAUS4, HAUS5, HAUS6, HAUS7 and HAUS8. Localizes to microtubules throughout all mitotic stages and localizes to the midbody during cytokinesis. Phosphorylation at Thr-882 during mitosis is required for interaction with TUBG1, HAUS1, HAUS2, HAUS3, HAUS4, HAUS5, HAUS6, HAUS7 and HAUS8 and their recruitment to spindle microtubules. Belongs to the WD repeat EMAP family.