Microtubule-associated protein which regulates cell division and neuronal migration during cortical development. Necessary for mitotic spindle organization (PubMed:19734894, PubMed:28370826). Necessary for radial and tangential cell migration during brain development, possibly acting as a regulator of cell morphology and process formation during migration (PubMed:22926142). May enhance calcium influx through CACNA1E and stimulate programmed cell death (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 (PubMed:15258581). Interacts with alpha-tubulin (PubMed:19734894). Widely expressed. Not detected in lymphocytes. Disease susceptibility is associated with variants affecting the gene represented in this entry. Disease susceptibility is associated with variants affecting the gene represented in this entry. Mutation Leu-229 may be a cause of intractable epilepsy of infancy. Affected individuals have seizures of multiple type, manifested as tonic, clonic, and myoclonic seizures in the neonatal period, and as tonic seizures activated frequently by sleep, and repeated frequent myoclonic seizures in later infancy. The seizures are unresponsive to numerous antiepileptic drugs, and infants die in the first years of life. Although heterozygosity for Leu-229 has been associated with relatively benign forms of epilepsy in adolescence, homozygosity for the same mutation has much more severe consequences. May be due to intron retention.