Growth factor receptor-bound protein 14 (GRB14)

Growth factor receptor-bound protein 14 (GRB14) is an adaptor protein that negatively regulates receptor tyrosine kinase (RTK) signaling, particularly insulin and insulin-like growth factor receptor pathways. It contains several functional domains, including a proline-rich region, RA domain, PH domain, BPS domain, and SH2 domain, enabling it to interact with membrane lipids and phosphorylated tyrosine residues. GRB14 modulates cell proliferation, metabolism, and possibly differentiation. It is highly expressed in liver, kidney, pancreas, testis, ovary, heart, and skeletal muscle. Phosphorylation of GRB14 can be mediated by serine and tyrosine kinases. GRB14 interacts with several RTKs and signaling proteins, including the insulin receptor, insulin-like growth factor receptor, epidermal growth factor receptor, fibroblast growth factor receptor 1, TNKS2, and CNGA1 channel subunit. By inhibiting key steps downstream of activated RTKs, GRB14 plays critical roles in physiological conditions and disease states such as diabetes and cancer. Mouse models lacking Grb14 exhibit altered lipid metabolism and changes in hepatic insulin sensitivity.

Inhibition or modulation of key steps downstream from activated tyrosine kinase receptors (e.g., INSR, IGF-1R), often through direct binding and steric hindrance or altered protein recruitment.