Collision coupling, crosstalk, and compartmentalization in G-protein coupled receptor systems: Can a single model explain disparate results?

JOURNAL OF THEORETICAL BIOLOGY

卷:255

Article

Brinkerhoff, Christopher J.¹  Traynor, John R.²  Linderman, Jennifer J.¹ 

[1] Univ Michigan, Dept Chem Engn, Ann Arbor, MI 48109 USA

[2] Univ Michigan, Sch Med, Dept Pharmacol, Ann Arbor, MI 48109 USA

关键词: Mathematical model;    Adrenergic;    Opioid;    Cannabinoid;    Muscarinic;   

DOI  :  10.1016/j.jtbi.2008.08.003

来源: Elsevier

【 摘 要 】

The collision coupling model describes interactions between receptors and G-proteins as first requiring the molecules to find each other by diffusion. A variety of experimental data on G-protein activation have been interpreted as suggesting (or not) the compartmentalization of receptors and/or G-proteins in addition to a collision coupling mechanism. In this work, we use a mathematical model of G-protein activation via collision coupling but without compartmentalization to demonstrate that these disparate observations do not imply the existence of such compartments. In experiments with GTP analogs (commonly GTP gamma S), the extent of G-protein activation is predicted to be a function of both receptor number and the rate of GTP analog hydrolysis. The sensitivity of G-protein activation to receptor number is shown to be dependent upon the assay used, with the sensitivity of phosphate production assays (GTPase) > GTP gamma S-binding assays > cAMP inhibition assays. Finally, the amount of competition or crosstalk between receptor species activating the same type of G-proteins is predicted to depend on receptor and G-protein number, but in some (common) experimental regimes this dependence is expected to be minimal. Taken together, these observations suggest that the collision coupling model, without compartments of receptors and/or G-proteins, is sufficient to explain a variety of observations in literature data. (C) 2008 Elsevier Ltd. All rights reserved.

【 授权许可】

Free