Modulates the assembly and organization of the microtubule cytoskeleton, and probably plays a role in regulating the orientation of the mitotic spindle and the orientation of the plane of cell division. Required for normal proliferation of neuronal progenitor cells in the developing brain and for normal brain development. Does not affect neuron migration per se. Homotrimer; self-association is mediated by the N-terminal coiled coil (By similarity). Does not interact with EML3 (By similarity). Binds repolymerizing microtubules (By similarity). Binds unpolymerized tubulins via its WD repeat region (By similarity). Interacts with TASOR (By similarity). Detected in cytoplasmic punctae. Co-localizes with microtubules. Enriched in perinuclear regions during interphase and in the region of spindle microtubules during metaphase. Enriched at the midzone during telophase and cytokinesis. Detected at growth cones in neurons. Contains a tandem atypical propeller in EMLs (TAPE) domain. The N-terminal beta-propeller is formed by canonical WD repeats; in contrast, the second beta-propeller contains one blade that is formed by discontinuous parts of the polypeptide chain. The N-terminal coiled coil is required for association with microtubules. Belongs to the WD repeat EMAP family.