Claim: PP1 is involved in regulation of various cellular processes and cardiac function hence observed in the end stage of heart failure.
Evidence: PP1 plays a crucial role in the regulation of blood-glucose levels in the liver and glycogen metabolism. PP1 is important to the reciprocal regulation of glycogen metabolism by ensuring the opposite regulation of glycogen breakdown and glycogen synthesis. Phosphorylase a serves as a glucose sensor in liver cells. This suggests that dysfunctional phosphatases play a role in Alzheimer's disease. It has been recognized that protein phosphatase-1 (PP1) serves as an important regulator of HIV-1 transcription. The protein also contributes to ebolavirus pathogenesis by dephosphorylating the viral transcription activator VP30, allowing it to produce viral mRNAs. The herpes simplex virus protein ICP34.5 also activates protein phosphatase 1, which overcomes the cellular stress response to viral infection; protein kinase R is activated by the virus' double-stranded RNA, and protein kinase R then phosphorylates a protein called eukaryotic initiation factor-2A (eIF-2A), which inactivates eIF-2A. Herpesviruses in turn evolved ICP34.5 to defeat the defense; ICP34.5 activates protein phosphatase-1A which dephosphorylates eIF-2A, allowing translation to occur again.