Protein phosphatase-1 (PP1) is a major serine/threonine phosphatase that regulates a variety of cellular functions. PP1 consists of a catalytic subunit (see PPP1CA; MIM 176875) and regulatory subunits that determine the subcellular localization of PP1 or regulate its function. PPP1R1C belongs to a group of PP1 inhibitory subunits that are themselves regulated by phosphorylation (Wang et al., 2008 [PubMed 18310074]).[supplied by OMIM, Feb 2010].