[Dynamic protein assemblies in biological membranes].

Abstract

The peculiarities of structural organization and functioning of enzymes in biological membranes are reviewed. Based on experimental data it is suggested that these peculiarities are due to the ability of many proteins to form intramembrane aggregates and assemblies differing in life-time and consisting of related and functionally different enzymes, which determines the structural and functional heterogeneity of biological membranes. The importance of formation of dynamical essembl es for the functioning of multienzyme systems is illustrated by the hormone--receptor--adenylate cyclase and redox carrier chains. The general principles of functioning of these systems (e. g. lateral diffusion of constituent components, formation of protein-protein aggregates with terminal life-time, etc.) are discussed. On the whole the biological membranes appear as microheterogenous dynamical structures, whose functioning strongly depends on aggregation-deaggregation of membrane proteins. These processes are affected (i. e. accelerated or decelerated) by a number of factors, such as, for instance, multienzyme system functioning, which also stabilize the molecular assemblies formed. It is assumed that changes in reciprocal intramembrane arrangement of the enzymes and formation of protein-protein complexes may control the local activity of membrane-dependent processes in the cell.