AKAPs act as scaffolding proteins co-ordinating phosphotase:kinase signaling at the cytoskeleton. They interact with PKAs and anchor them to specific sub-cellular compartments and participate in multiple cellular processes including growth, metabolism and differentiation. ASP, a 26KD protein, is a novel AKAP-interacting protein. It interacts with the amphipathic helix of AKAP3 and facilitates AKAP3-PKA interactions. It consists of a conserved N-terminal AKAP-binding domain and a central cysteine-rich Fz domain. It is specifically expressed in the sperms and might play a significant role in sperm motily and also facilitate cytoskeletal reorganization during spermiogenesis.