RRAD (Ras-related glycolysis inhibitor and calcium channel regulator) is a small GTPase that functions as a multifaceted regulator of calcium signaling and cellular metabolism. In cardiac tissue, RRAD negatively regulates L-type calcium channels (LTCC) by binding to channel β subunits and inhibiting channel open probability 1. β-adrenergic stimulation relieves this inhibition through protein kinase A-mediated phosphorylation of RRAD, enabling increased calcium influx and enhanced contractility 1. RRAD also inhibits cardiac hypertrophy via the CaMKII pathway, suggesting a protective role in heart disease 2. Notably, RRAD knockout in a dilated cardiomyopathy model paradoxically rescued systolic function and pathological remodeling while restoring calcium handling 3, revealing complex therapeutic potential for heart failure treatment. In cancer, RRAD exhibits context-dependent roles as both oncogene and tumor suppressor. RRAD downregulation promotes glucose metabolism and tumor progression in oral squamous cell carcinoma and papillary thyroid cancer through calcium-dependent activation of transcription factors regulating glucose transporters 4, 5. Conversely, RRAD functions as a tumor suppressor in ovarian cancer, where Ras-mediated epigenetic silencing promotes oncogenic glucose uptake 6. Additionally, RRAD regulates cell surface tension in senescent cells 7. These findings establish RRAD as a crucial regulator linking calcium homeostasis, metabolic adaptation, and disease progression across multiple tissue types.