Insulin interactions with its receptors: Experimental evidence for negative cooperativity

doi:10.1016/S0006-291X(73)80072-5

Biochemical and Biophysical Research Communications

Volume 55, Issue 1, 1 November 1973, Pages 154-161

https://doi.org/10.1016/S0006-291X(73)80072-5 Get rights and content

Summary

A simple method is reported to detect cooperative interactions in the binding of polypeptide hormones to their membrane receptors. The dissociation of radioiodinated hormone from the receptor is studied under two conditions: first, by diluting the hormone-receptor complex sufficiently to prevent rebinding of the dissociated tracer; second, by dilution to the same extent in a medium containing an excess of unlabeled hormone. If the sites are independent, the dissociation rates must be the same in both cases. If the presence of unlabeled hormone increases the dissociation rate of the tracer, negatively cooperative interactions must occur. Insulin receptors on cultured lymphocytes and liver plasma membranes show negative cooperative interactions. Growth hormone receptor sites lack these interactions.

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Citation Excerpt :
Recent cryo-electron microscopy (cryo-EM) studies of HI bound to the intact IR ectodomain and holoreceptor under ligand-saturated conditions (20–24) describe the mechanism by which the hormone also binds to the canonical ABE β-sheet of domain FnIII-1, that of HI binding site 2. The relationship of this site to early kinetic and complex negative cooperativity studies (25,26) remains, however, unclear. Ascribed to the lower-affinity site 2 (≈400 nM) (17,19), the hormone engages the FnIII-1 domain via residues of the hormone spatially opposite to those which participate in the binding to site 1.
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¹: Fellow of the Belgian F.N.R.S.; recipient of a PHS International Postdoctoral Fellowship FO5 TW 1918-02.

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Insulin interactions with its receptors: Experimental evidence for negative cooperativity

Summary

Metabolism

J. Biol. Chem.

J. Theor. Biol.

Biochim. Biophys. Acta

J. Biol. Chem.

Biochem. Biophys. Res. Commun.

Arch. Biochem. Biophys.

J. Mol. Biol.

Biochem. Biophys. Res. Commun.

J. Biol. Chem.

FEBS Letters

Clin. Res.

Ann. N. Y. Acad. Sci.

Nature New Biol.