Essential for the stability of microtubules (MTs) (PubMed:17196341). Essential for the formation of MTs (By similarity). Required for the organization of the mitotic spindle and for the proper attachment of kinetochores to MTs (By similarity). Promotes the recruitment of NUDC to the mitotic spindle for mitotic progression (By similarity). Homotrimer; self-association is mediated by the N-terminal coiled coil (By similarity). Interacts (via WD repeats) with NUDC (By similarity). Interacts with alpha- and beta-tubulin during mitosis (By similarity). Localizes to microtubules (MTs) during interphase with a significantly reduced affinity for MTs during mitosis. Phosphorylated during mitosis (By similarity). Phosphorylation at Ser-144 and Ser-146 promotes its dissociation from microtubules during mitosis which is required for efficient chromosome congression (By similarity). Belongs to the WD repeat EMAP family.