Adapter protein which modulates coupling of cell surface receptor kinases with specific signaling pathways. Binds to, and suppresses signals from, the activated insulin receptor (INSR). Potent inhibitor of insulin-stimulated MAPK3 phosphorylation. Plays a critical role regulating PDPK1 membrane translocation in response to insulin stimulation and serves as an adapter protein to recruit PDPK1 to activated insulin receptor, thus promoting PKB/AKT1 phosphorylation and transduction of the insulin signal. {ECO:0000269|PubMed:15210700, ECO:0000269|PubMed:19648926}. This is the function of Ensembl gene identifier ENSG00000115290 (GRB14, growth factor receptor bound protein 14).