The ADRB1 protein, also known as the beta-1 adrenergic receptor, is a G-protein coupled receptor (GPCR) encoded by the ADRB1 gene, which is located on chromosome 10q24-26. It is predominantly expressed in cardiac tissues such as the cardiac pacemaker and myocardium, where it plays a crucial role in mediating the physiological effects of epinephrine and norepinephrine. When activated by these catecholamines, ADRB1 increases heart rate, conduction, and contractility, contributing to the regulation of cardiovascular functions. Additionally, it is also found in the cerebral cortex and juxtaglomerular cells of the kidney, where it can influence renin release. The receptor is coupled to the Gs G-protein/adenyl cyclase signal transduction pathway, which is central to its regulatory functions. Variants of the ADRB1 gene, such as the Arg389Gly polymorphism, have been associated with differences in receptor functionality, impacting conditions like hypertension and heart failure. ADRB1 is a key target for beta-blockers, which are widely used in the treatment of cardiovascular diseases.