An alternative scenario for the formation of specialized protein nano-domains (cluster phases) in biomembranes

¹ Université de Toulouse; UPS; Laboratoire de Physique Théorique (IRSAMC) - F-31062 Toulouse, France, EU
² CNRS; LPT (IRSAMC) - F-31062 Toulouse, France, EU

^a nicolas.destainville@irsamc.ups-tlse.fr

Received: 19 July 2010
Accepted: 19 August 2010

Abstract

We discuss a realistic scenario, accounting for the existence of sub-micrometric protein domains in cell membranes. At the biological level, such membrane domains have been shown to be specialized, in order to perform a determined biological task, in the sense that they gather one or a few protein species out of the hundreds of different ones that a cell membrane may contain. By analyzing the balance between mixing entropy and protein affinities, we propose that such protein sorting in distinct domains can be explained without appealing to pre-existing lipidic micro-phase separations, as in the lipid raft scenario. We show that the proposed scenario is compatible with known physical interactions between membrane proteins, even if thousands of different species coexist.