Microtubule-associated protein that promotes microtubule bundling and stabilizes microtubules against depolymerization in response to cold shock (PubMed:16206169). Microtubule-associated protein involved in the stabilization of microtubules along the axis of migration during radial intercalation. Promotes the establishment and stabilization of an axis of microtubules required for the active migration of cells into the outer epithelium (By similarity). Essential for ciliary central apparatus formation which requires both its microtubule-binding and bundling activities and for ciliary localization of HYDIN and SPAG6 in ependymal cilia (PubMed:30535028). Binds actin in intestinal epithelial cells (IECs), essential for IECs survival and contributes to formation of filopodia and lamellipodia in migrating IECs (By similarity). Regulates planar cell polarity signaling pathway and asymmetric microtubule accumulation in ciliated epithelia (By similarity). Homodimer (PubMed:30535028). Interacts with actin, TJP1, CGN and CDH1 (By similarity). Also found at the apical tip of cilia (PubMed:30535028). Present in the tails of developing and epididymal sperm, internal to the fibrous sheath and around the outer dense fibers of the sperm flagellum (PubMed:15979255). Colocalizes with TJP1 and CGN at sites of cell-cell contact in intestinal epithelial cells (By similarity). Expressed predominantly in the seminiferous epithelium of adult testis (PubMed:15979255). Expressed in pillar cells of the organ of Corti (at protein level). Expressed in brain, kidney, lung and testis (PubMed:16206169, PubMed:30535028). Highly expressed in the trachea, lung and oviduct (PubMed:30535028). Expression is first detected in the testis at 3 weeks and continues to adulthood. The Calponin-homology domain mediates its binding to microtubules. Depletion in ependymal cells by RNAi completely abolishes the central pair microtubules and markedly attenuates ciliary localizations of HYDIN and SPAG6, resulting in rotational beat of the ependymal cilia. Radial intercalation is a developmentally reiterated form of migration by which cells move in a direction orthogonal to the plane of the tissue from an inner layer to an outer layer.