By: Rodrigo Almeida
From: Universidade de Lisboa
At: Faculdade de Ciências, Ed. C8, 8.2.06
The most widespread feature of biomembranes is probably their fluidity. After the recognition that the distribution of molecules in the plane of this quasi-bidimensional fluid is far from random, several models have been proposed to explain the lateral compartmentalization of membranes. Whereas many of those rely on the formation of (supra)molecular assemblies involving proteins, some obstinate biophysicists insisted that the phase behavior of lipids could be responsible, at least in part, for the controlled lateral segregation of molecules. In this context, the model of lipid rafts, based on the concept of fluid/fluid phase separation of lipids, was widely accepted as a suitable explanation for many new experimental data.
In this seminar, results will be presented that imply a revision of the lipid raft model, in order to include the presence of “solid” lipid phases and strongly interacting stoichiometric complexes of lipids. Biomembranes will be paralleled to amorphous materials, and the organization of functional domains described as a 2-D crystallization process.