PPA1 (inorganic pyrophosphatase 1) is a metabolic enzyme that catalyzes pyrophosphate hydrolysis, playing critical roles across multiple physiological systems. In adipose tissue, PPA1 promotes adipogenesis by stabilizing C/EBPβ and C/EBPδ proteins in a catalytic-activity-independent manner 1, and facilitates adipocyte browning through regulation of mitochondrial biogenesis as a target gene of NRF1 2. PPA1 deficiency causes lipodystrophy, hepatic steatosis, and insulin resistance, while overexpression restores adipogenesis in diabetic models. In the nervous system, cell-penetrating TAT-PPA1 protects dopaminergic neurons against oxidative stress and MPTP-induced damage by suppressing MAPK signaling and ROS production, suggesting potential for Parkinson's disease treatment 3. Conversely, PPA1 is significantly upregulated in multiple cancers—particularly lung, ovarian, gastric, and pancreatic cancers—where high expression correlates with advanced stages, poor prognosis, and metastasis 456. In cancer cells, PPA1 promotes proliferation through Wnt/β-catenin and TP53/p21 pathways; its suppression increases apoptosis. PPA1 was identified as a therapeutic target for diabetic microangiopathy through genome-wide Mendelian randomization analysis 7. Recent molecular docking studies identified devazepide and quinotolast as potential PPA1 inhibitors for cancer repurposing 8. These findings position PPA1 as a dual-function protein: beneficial in metabolic and neurodegenerative contexts, but oncogenic in cancer.