Serious doubt is cast on widely accepted models of how a crucial class of cell surface receptors organize themselves, in a report to be published in the December 2006 issue of Nature Methods.
Large proteins imbedded in the membranes of our cells mediate many of our most fundamental biological functions. Taste and smell result from small molecules in food and air binding to these proteins to trigger specific responses in the sensory cells that are then relayed to our brains. These proteins, called G-protein coupled receptors, also mediate many critical internal biological processes that involve communication between cells and are a principal target of many therapeutic drugs.
These receptors were thought to function like single sentinels manning the walls of an isolated outpost. Each looks for signals from the outside and relays them to innumerable others within the walls so that everyone can respond appropriately.
In the 1990s evidence started to show that these receptors did not function as lone sentinels but as pairs who cooperated in relaying each outside signal. But it was difficult to determine if each sentinel was truly acting alone or in concert with another.
Simon Davis and colleagues made adaptations to the principal experiment used to examine the organization of these cell membrane receptors in an attempt to make the results more conclusive. After testing the method on several different membrane receptors it appears that at least some of these receptor types only interact randomly and do not form true pairs.
In an accompanying News & Views Martin Lohse comments on these changing models of G-protein coupled receptor function and calls for a re-assessment of reports of dimer formation.
Simon Davis (University of Oxford, United Kingdom)
Additional contact for comment on paper:
Martin Lohse (University of Wuerzburg, Germany)
Abstract available online.
(C) Nature Methods press release.
Message posted by: Trevor M. D'Souza