Table 1.

Major features of the common protein serine/threonine phosphatases

Family	Common name	Regulation	References
PPP	Protein Phosphatse 1 (PP1)	activity regulated by targeting/inhibitory subunits	(Cohen 2002)
	Protein Phosphatase 2A (PP2A)	Heterotrimer of A/B/C subunits; activity B subunit and C subunit methylation regulates	(Xu, Xing et al. 2006; Wang, Zhang et al. 2008)
	Protein Phosphatase 2B (PP2B), Calcineurin	Ca2+/Calmodulin	(Rusnak and Mertz 2000; Shibasaki, Hallin et al. 2002)
PPM	Protein Phosphatase 2C (PP2C)	Isoform specific mechanisms	(Lu and Wang 2008)