The GRK (G protein-coupled receptor kinase) family includes several members that regulate signaling by phosphorylating G protein-coupled receptors (GPCRs). The structure of GRKs features a conserved kinase domain and regulatory regions, allowing specific recognition and action on GPCRs. These kinases are primarily located in the cytoplasm and on the cell membrane, participating in regulating a variety of physiological processes, including the cardiovascular system, vision, and neurotransmission. The expression of GRKs varies among different tissues, with mutations or changes in expression associated with the development of various diseases, including heart disease, depression, and cancer.