Microtubule-associated protein which regulates cell division and neuronal migration during cortical development. Necessary for mitotic spindle organization. Necessary for radial and tangential cell migration during brain development, possibly acting as a regulator of cell morphology and process formation during migration (By similarity). May enhance calcium influx through CACNA1E and stimulate programmed cell death. Overexpression of EFHC1 in hippocampal primary culture neurons induced apoptosis (PubMed:15258581). Microtubule inner protein (MIP) part of the dynein-decorated doublet microtubules (DMTs) in cilia axoneme, which is required for motile cilia beating (By similarity). Interacts with the C-terminus of CACNA1E. InteractS with alpha-tubulin. Expressed in adult brain including hippocampus, cerebellum, cerebral cortex, thalamus, hypothalamus, amygdala and upper brainstem. Expressed in soma and dentrites of pyramidal neurons of the hippocampal CA1 region, pyramidal neurons of the cerebral cortex and Purkinje cells of cerebellum. Highly expressed in testis, trachea, and oviduct, moderately in lung, and slightly in brain. Highly expressed in sperm flagella and tracheal cilia (at protein level).