Signal initiation in biological systems: the properties and detection of transient extracellularprotein interactions

Abstract

Individual cells within biological systems frequently coordinate their functions through signals initiated by specific extracellularprotein interactions involving receptors that bridge the cellular membrane. Due to their biochemical nature, these membrane-embedded receptorproteins are difficult to manipulate and their interactions are characterised by very weak binding strengths that cannot be detected using popular high throughput assays. This review will provide a general outline of the biochemical attributes of receptorproteins focussing in particular on the biophysical properties of their transient interactions. Methods that are able to detect these weak extracellular binding events and especially those that can be used for identifying novel interactions will be compared. Finally, I discuss the feasibility of constructing a complete and accurate extracellularprotein interaction map, and the methods that are likely to be useful in achieving this goal.