This gene encodes a protein with an N-terminal thioredoxin domain and three C-terminal nucleoside diphosphate kinase (NDK) domains, but the NDK domains are thought to be catalytically inactive. The sea urchin ortholog of this gene encodes a component of sperm outer dynein arms, and the protein is implicated in ciliary function. Mutations in this gene are implicated in primary ciliary dyskinesia type 6.[provided by RefSeq, Nov 2009].
Function: Probably required during the final stages of sperm tail maturation in the testis and/or epididymis, where extensive disulfide bonding of fibrous sheath (FS) proteins occurs. May be involved in the reduction of disulfide bonds within the sperm FS components. In vitro, it has neither NDP kinase nor reducing activity on disulfide bonds.