May play a role in spermatogenesis. May be involved in differentiation or function of ciliated cells (By similarity). Interacts with alpha-tubulin. Localizes to the manchette in elongating spermatids. Predominantly perinuclear in bronchial epithelial cells but also detected in the nucleus in some primary epithelial cells and in a number of cell lines (By similarity). Belongs to the SMRP1 family. Truncated C-terminus.