SAPS3 also known as PP6R3 (protein Ser/Thr phosphatase 6 regulatory subunit 3) is a regulatory subunit for the protein phosphatase-6 catalytic subunit which is important for cell survival and is associated with TOR signaling in yeast. SAPS3 has been implicated in the transition from G1 to the S phase of mitosis. The SAPS3 subunit is one of three human versions of SAPs which may also have a role to play in regulation of NF-kappaB. Protein phosphatase regulatory subunits, such as SAPS3, modulate the activity of protein phosphatase catalytic subunits by restricting substrate specificity, recruiting substrates, and determining the intracellular localization of the holoenzyme.