Protein phosphatase 1 regulatory subunit 1A

Protein phosphatase 1 regulatory subunit 1A (PPP1R1A) is an inhibitor of protein phosphatase 1 that plays a regulatory role in hormonal control of glycogen metabolism (UniProt: Q13522). The protein functions by inhibiting PP1 activity in response to elevated intracellular cAMP, allowing cAMP-dependent signaling to regulate proteins beyond those directly phosphorylated by PKA. It is also subject to inactivation by calcineurin following calcium elevation, providing a mechanism for cross-talk between signaling pathways.

PPP1R1A is expressed broadly across tissues involved in metabolic regulation and signal transduction (UniProt: Q13522). The protein's role in cAMP-dependent phosphorylation cascades positions it at a key control point in hormonal signaling networks.

In Alzheimer's Disease, PPP1R1A is significantly upregulated in post-mortem brain tissue from AD patients compared to age-matched controls (Chaparral AD proteomics). The mean log2 fold-change is 0.8464, indicating approximately 1.8-fold elevation. This upregulation was detected across subcellular fractions in a TMT-labeled quantitative proteomics study, suggesting altered PP1 inhibitory signaling may contribute to pathological changes in AD brain metabolism and phosphorylation dynamics.