GRK2 is a serine/threonine kinase that primarily functions as a desensitizer of G protein-coupled receptors (GPCRs) through agonist-dependent phosphorylation 1. It phosphorylates activated β-adrenergic receptors and anaphylatoxin receptors (C3AR1, C5AR1), inducing receptor desensitization 23. GRK2 regulates lysophosphatidic acid receptor (LPAR1) signaling through both phosphorylation-dependent and independent mechanisms 4. The kinase also positively regulates Hedgehog signaling by facilitating smoothened trafficking into cilia. Structurally, GRK2 creates distinct phosphorylation 'barcodes' on receptor C-terminal tails that differentially engage arrestin isoforms, potentially generating unique downstream cellular outcomes 5. Beyond canonical GPCR desensitization, GRK2 exhibits broader physiological roles. It regulates vascular smooth muscle cell phenotype through DNMT1-mediated epigenetic reprogramming 6 and controls glucose metabolism in macrophages via PKM2 phosphorylation and de-succinylation 7. Emerging evidence indicates GRK2 localizes to mitochondria and influences mitochondrial dynamics, oxidative phosphorylation, and apoptosis 8. Clinically, GRK2 dysregulation is implicated in multiple pathologies including heart failure, pulmonary arterial hypertension 9, rheumatoid arthritis, and hepatocellular carcinoma 10. GRK2 inhibition represents a promising therapeutic strategy for cardiovascular and immune-inflammatory diseases 1112.