Microtubule inner protein (MIP) part of the dynein-decorated doublet microtubules (DMTs) in flagellum axoneme. May serve to reinforce and thus stabilize the microtubule structure in the sperm flagella.
Subcellular locations: Cytoplasm, Cytoskeleton, Flagellum axoneme
Localizes to the A-tubules of DMTs.
Expressed in testis, prostate and placenta.