K4 Elite
K4 Elite
A splice variant of insulin-like growth factor 1 expressed in mechanically stressed and damaged muscle, whose unique C-terminal E-domain peptide is studied for roles in satellite-cell activation and early tissue-repair signaling.
Mechano Growth Factor (MGF) is an alternatively spliced isoform of insulin-like growth factor 1, also designated IGF-1Ec. It is produced locally in skeletal muscle in response to mechanical loading and tissue damage. What distinguishes MGF from systemic IGF-1 is its distinct C-terminal E-domain, an inserted peptide sequence generated by the alternative splicing event.
Research interest centers on this E-domain peptide, which in experimental systems appears to act independently of the mature IGF-1 domain to influence muscle stem (satellite) cells. Many laboratory studies use a synthetic peptide corresponding to the unique MGF C-terminal region rather than the full-length protein.
MGF is handled exclusively as a research reagent for the study of muscle repair and growth-factor signaling.
The full-length MGF molecule contains a mature IGF-1 region capable of engaging the IGF-1 receptor, but its distinctive C-terminal E-domain peptide is reported to have separate biological activity. In cell-culture studies this peptide has been associated with activation and proliferation of muscle satellite cells, which are progenitors involved in muscle repair after mechanical stress.
The E-domain peptide's actions in experimental models appear not to require IGF-1R binding, and investigators have proposed distinct, as-yet incompletely defined receptor or signaling interactions to account for its effects on stem-cell recruitment.
The following summarize published experimental studies for reporting purposes only and are not usage instructions.
Goldspink and Yang characterized MGF as a mechanically activated IGF-1 splice variant, reporting that its expression rises in muscle after resistance loading or damage and that the E-domain peptide stimulates satellite-cell proliferation in culture (Yang & Goldspink, 2002).
Preclinical cardiac studies have reported that administration of the MGF C-terminal peptide in animal models of myocardial injury was associated with markers of reduced cardiomyocyte loss; these findings are cited as research observations only.
Combinations examined in the research literature. Descriptive only — not a recommendation to combine compounds.
References are being compiled for this entry.