PP2C beta/PPM1B: ProductsProtein phosphatase 2C beta (PP2C beta), also called protein phosphatase, magnesium-dependent type 1B (PPM1B), preferentially dephosphorylates serine and threonine residues on proteins. There are five splice variants with sizes of 53, 43, 42, 36, and 21 kDa. This enzyme is resistant to inhibitors of other protein phosphatases such as okadaic acid and calyculin. Association of PP2C beta with I-kappa-B kinase inhibits its phosphorylating activity and is regulated by TNF alpha stimulation. PP2C beta is found in many cell types and tissues, especially muscle. The mRNA for PP2C beta accumulates in mature spermatocytes and metaphase-arrested, unfertilized oocytes. Knockout of PP2C beta in mice is lethal prior to embryo implantation.