IGF-I/IGF-1 Protein, Human (P. pastoris, N-His)

The LR3 IGF-I/IGF-1 protein, structurally and functionally akin to insulin, boasts significantly heightened growth-promoting activity compared to its counterpart. Positioned as a potential physiological regulator, LR3 IGF-I may govern [1-14C]-2-deoxy-D-glucose (2DG) transport and glycogen synthesis in osteoblasts, demonstrating effective stimulation of glucose transport in bone-derived osteoblastic (PyMS) cells even at markedly lower concentrations than insulin. Its multifaceted roles extend to potential involvement in synapse maturation and the Ca(2+)-dependent exocytosis essential for sensory perception of smell in the olfactory bulb. Operating as a ligand for IGF1R, LR3 IGF-I binds to the alpha subunit, initiating the activation of intrinsic tyrosine kinase activity, autophosphorylating tyrosine residues in the beta subunit. This activation triggers a cascade of downstream signaling events leading to the activation of the PI3K-AKT/PKB and Ras-MAPK pathways. Further, LR3 IGF-I forms crucial ternary complexes with integrins (ITGAV:ITGB3 and ITGA6:ITGB4) and IGFR1, essential for comprehensive IGF1 signaling, influencing the phosphorylation and activation of IGFR1, MAPK3/ERK1, MAPK1/ERK2, and AKT1. It also exhibits diverse molecular interactions, including with SH2D3C isoform 2.