Insulin‐like growth factor I binding and receptor kinase in red and white muscle
1988; Wiley; Volume: 234; Issue: 2 Linguagem: Inglês
10.1016/0014-5793(88)80093-0
ISSN1873-3468
AutoresAntónio Zorzano, David E. James, Neil B. Ruderman, Paul F. Pilch,
Tópico(s)Neurobiology and Insect Physiology Research
ResumoIGF‐I receptors were partially purified from red and white skeletal muscle by lectin‐affinity chromatography and the resultant fraction was depleted of insulin receptors by insulin affinity chromatography. Equilibrium binding of 125 I‐IGF‐I to receptor preparations from red and white muscle yielded identical Scatchard plots. The integrity of the IGF‐I receptor preparation in the two fiber types was identical as determined by affinity cross‐linking. The tyrosine kinase activity of the receptor from red muscle was 2–3‐fold more active towards exogenous substrates in both the basal and ligand‐activated states as compared to white muscle. These data show that there is IGF‐I‐dependent kinase activity intrinsic to IGF‐I receptors from skeletal muscle, and suggest that identical cellular factors may regulate the kinase activity of insulin and IGF‐I receptors in a parallel manner in vivo.
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