IGF-1 LR3

IGF-1 LR3 activates the IGF-1 receptor (IGF-1R), a receptor tyrosine kinase, initiating autophosphorylation of intracellular tyrosine residues and downstream activation of the PI3K/Akt/mTOR and Ras/MAPK/ERK signaling cascades, which are studied in the context of cell proliferation, protein synthesis regulation, and apoptosis suppression across a broad range of cell lines. The Arg3 substitution and N-terminal extension substantially reduce IGFBP-3 and IGFBP-5 binding affinity, making IGF-1 LR3 a preferred research tool over native IGF-1 for long-duration cell culture experiments where IGFBP-mediated sequestration would otherwise limit bioavailability. Published research has employed this analog to study myoblast differentiation, satellite cell activation, and skeletal muscle hypertrophy signaling in C2C12 cultures, as well as hepatocyte glucose uptake via GLUT4 translocation. It is also used in comparative receptor binding studies examining IGF-1R versus insulin receptor (IR) cross-reactivity and downstream signal divergence.