| Abstract: | Background Sperm protein 17 (Sp17) is a three-domain protein that contains: 1) a highly conserved N-terminal domain that is 45% identical to the human type II alpha regulatory subunit (RII alpha) of protein kinase A (PKA); 2) a central sulphated carbohydrate-binding domain; and 3) a C-terminal Ca++/calmodulin (CaM) binding domain. Although Sp17 was originally discovered and characterized in spermatozoa, its mRNA has now been found in a variety of normal mouse and human tissues. However, Sp17 protein is found predominantly in spermatozoa, cilia and human neoplastic cell lines. This study demonstrates that Sp17 from spermatozoa binds A-kinase anchoring protein 3 (AKAP3), confirming the functionality of the N-terminal domain. |
