IGF-1 LR3 (Research Overview)
IGF-1 LR3 (Long R3 Insulin-like Growth Factor-1) is an 83-amino-acid analog of human IGF-1 that carries an arginine substitution at position 3 and a 13-amino-acid N-terminal extension. It is widely used in cell-culture and signaling research.
Mechanism of Action
IGF-1 LR3 activates the IGF-1 receptor, a receptor tyrosine kinase, which signals mainly through the PI3K–Akt and MAPK–ERK pathways that regulate protein synthesis, survival, and proliferation in cultured cells. The Arg3 substitution and N-terminal extension greatly reduce binding to IGF-binding proteins (IGFBPs), which is why the analog has a much longer active half-life than native IGF-1 in experimental systems.
Because IGFBPs normally sequester free IGF-1, the reduced binding makes LR3 a potent and stable ligand for receptor-signaling studies. Receptor affinity and potency relative to native IGF-1 have been characterized in published binding and signaling assays.
Research Areas
A long-standing research use is as a growth-factor supplement in serum-free cell-culture media, where it supports proliferation and viability of many cell lines.
Published studies have also used IGF-1 LR3 in myoblast and satellite-cell cultures, to examine differentiation, hypertrophy signaling, and the interaction between IGF-1 and other growth-factor pathways. Additional work has examined its role in cell-survival and anti-apoptotic signaling in vitro.
Findings from animal or in-vitro systems do not establish safety or efficacy for any indication and should not be interpreted as medical claims.
Specification summary
IGF-1 LR3
Stated purity ≥99%. For laboratory research use only.
Related materials
References
- King R, Wells JR, Krieg P, Snoswell M, Brazier J, Bagley CJ, et al. Production and characterization of recombinant insulin-like growth factor-I (IGF-I) and potent analogues of IGF-I, with Gly or Arg substituted for Glu3, following their expression in Escherichia coli as fusion proteins. J Mol Endocrinol. 1992;8(1):29-41. PMID 1311930 · DOI
- Francis GL, Ross M, Ballard FJ, Milner SJ, Senn C, McNeil KA, et al. Novel recombinant fusion protein analogues of insulin-like growth factor (IGF)-I indicate the relative importance of IGF-binding protein and receptor binding for enhanced biological potency. J Mol Endocrinol. 1992;8(3):213-23. PMID 1378742 · DOI
- Tomas FM, Lemmey AB, Read LC, Ballard FJ. Superior potency of infused IGF-I analogues which bind poorly to IGF-binding proteins is maintained when administered by injection. J Endocrinol. 1996;150(1):77-84. PMID 8708565 · DOI
- Werner H. The IGF1 Signaling Pathway: From Basic Concepts to Therapeutic Opportunities. Int J Mol Sci. 2023;24(19). PMID 37834331 · DOI
- Bach LA. IGF-binding proteins. J Mol Endocrinol. 2018;61(1):T11-T28. PMID 29255001 · DOI
Cited literature is provided for scientific context only and does not describe or endorse any use of these products.
For laboratory research use only. Not for human or veterinary use. Not intended to diagnose, treat, cure, or prevent any disease.