Acts as a regulator of cilium basal body docking and positioning in mono- and multiciliated cells. Regulates basal body docking and cilia formation in multiciliated lung cells. Regulates kinocilium positioning and stereocilia bundle morphogenesis in the inner ear. Interacts with DLG3. Localizes to the apical cell membrane, the basal body and the primary cilium in monociliated node cells. Microtubule inner protein (MIP) part of the dynein-decorated doublet microtubules (DMTs) in cilia axoneme (By similarity). Expressed in mono- and multiciliated tissues during planar cell polarity acquisition. First detected in the embryonic node at 7.5 dpc. At 8.5-13.5 dpc, strong expression is detected in tissues that are either mono- or multiciliated, such as the eye, notochord, floor plate of the neural tube and all 4 choroid plexi. Expressed during development and early postnatal life in all 6 sensory regions of the inner ear. mice were born at the expected Mendelian ratio and are viable and fertile but show basal body docking and ciliogenesis defects in multiciliated lung cells. Belongs to the Flattop family.