Based on limited published evidence, PP2D1 is a metal-dependent serine/threonine protein phosphatase belonging to the PP2C (PPM) phosphatase family 1. The protein contains a conserved catalytic core domain that binds manganese/magnesium ions and exhibits protein serine/threonine phosphatase activity. GO annotations indicate PP2D1 localizes to the cytoplasm and nucleus, where it participates in signal transduction and negative regulation of the MAPK cascade. PP2D1 is expressed in male reproductive tissues; however, CRISPR/Cas9 knockout studies demonstrate it is individually dispensable for male mouse fertility 2.