| abstract |
dimerization/docking (D/D) domains found in the cAMP-dependent protein kinase regulatory subunit (PRKAR) and the DPY30/SDC1-like family. The ROP subfamily includes ropporin-1A (ROP1A, also called cancer/testis antigen 91, CT91, or rhophilin-associated protein 1A), ropporin-1B (ROP1B, also called rhophilin-associated protein 1B), and ropporin-1-like protein (ROPN1L, also called ROPN1-like protein, AKAP-associated sperm protein, or ASP). ROP1A, ROP1B and ROPN1L play important roles in male fertility. They are involved in fibrous sheath integrity and sperm motility and play roles in cAMP-dependent protein kinase (PKA)-dependent signaling processes required for spermatozoa capacitation. Members of this subfamily contain a conserved helical bundle domain that shows high sequence similarity to the dimerization/docking (D/D) domain of the regulatory subunit of PKA, which dimerizes to form a four-helix bundle that serves as a docking site for A-kinase-anchoring proteins (AKAPs). ROP1A and ROP1B have been shown to bind AKAP3. |