Updated project metadata. Phosphoprotein phosphatase 1 catalytic subunit gamma 2 (PPP1CC2), a PPP1 isoform restricted to testicular germ cells and spermatozoa, is essential for completion of spermatogenesis and highly similar PPP1C isoforms are capable of compensating for the loss of Ppp1cc in every tissue except in testis. In addition, inhibition of the enzymatic activity of PPP1C in spermatozoa stimulates motility. The key to understand the regulation of PPP1CC2 lies in the identification and characterization of its interacting partners. By integrating tissue-specific protein expression and protein-protein interaction data, we identified testis/sperm-enriched/specific PPP1CC complexes and potential key PPP1 interacting proteins (PIPs) for male reproduction. We constructed a testis/sperm-enriched network, analyzed several topological properties and specified the biological/physiological properties of the proteins in the network. Proteins were classified into modules according to their topological features and functional annotations, which clarified the mechanisms underlying testis and sperm function and, more specifically, the role of PPP1CC in spermatogenesis and sperm motility. Previously uncharacterized PIPs, such as AKAP4, were identified based on analyses of the interaction network. The PPP1CC2 interaction with AKAP4 in human sperm was also validated by different methods and the complex was proposed as potential targets for male contraception due to its significance in spermatozoa motility.