PPP1R1A (protein phosphatase 1 regulatory inhibitor subunit 1A) functions as a potent inhibitor of protein phosphatase 1 (PP1), playing critical roles in cellular signaling and metabolic regulation 1. The protein requires PKA-mediated phosphorylation at Thr35 for activation, which enables PP1 binding and inhibition, thereby increasing phosphorylation levels of various PP1 substrates 1. In pancreatic β-cells, PPP1R1A is essential for proper insulin secretion and glucose homeostasis, with its expression regulated by the transcription factor MafA 23. PPP1R1A levels correlate with GLP1-mediated insulin secretion amplification, and reduced expression in type 2 diabetic islets contributes to β-cell dysfunction and dedifferentiation 2. The gene shows tissue-specific expression patterns, with highest levels in muscle tissues and α-cells within pancreatic islets 3. In cancer contexts, PPP1R1A demonstrates tumor-suppressive properties in hepatocellular carcinoma, where higher expression correlates with better prognosis 4, while it promotes tumorigenesis and metastasis in Ewing sarcoma through the PKA/PPP1R1A/PP1 pathway 1. PPP1R1A also serves as a potential biomarker, with elevated plasma levels associated with worse prognosis in colorectal cancer 5.