Tubulin binding protein that inhibits microtubule nucleation and growth, resulting in shorter microtubules. Interacts with GRID2 and may also interact with GRID1 (PubMed:11829466). Interacts with EML3 (By similarity). Binds unpolymerized tubulins via its WD repeat region (By similarity). Colocalizes with the microtubule cytoskeleton. Colocalizes with the mitotic spindle. Widely expressed in both brain and peripheral tissues, including brainstem and enrichment in the postsynaptic density, PSD. 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 (By similarity). Belongs to the WD repeat EMAP family.