This gene encodes a member of the ropporin family. The encoded protein is a sperm protein. It interacts with A-kinase anchoring protein, AKAP3, through the amphipathic helix region of AKAP3. Type II regulatory subunit of cAMP-dependent protein kinase (PKARII) also binds to this helix domain of AKAP3, which allows PKARII to be targeted to specific subcellular compartments. It is suggested that sperm contains several proteins that bind to AKAPs in a manner similar to PKARII, and this encoded protein may be one of them. Alternatively spliced transcript variants encoding the same protein have been found for this gene.[provided by RefSeq, Jan 2011]