title: Interaction of the human N-Ras protein with lipid raft model membranes of varying degrees of complexity.
abstract: Ternary lipid mixtures composed of cholesterol, saturated (frequently with sphingosine backbone), and unsaturated phospholipids show stable phase separation and are often used as model systems of lipid rafts. Yet, their ability to reproduce raft properties and function is still debated. We investigated the properties and functional aspects of three lipid raft model systems of varying degrees of biological relevance--PSM/POPC/Chol, DPPC/POPC/Chol, and DPPC/DOPC/Chol--using 2H solid-state nuclear magnetic resonance (NMR) spectroscopy, fluorescence microscopy, and atomic force microscopy. While some minor differences were observed, the general behavior and properties of all three model mixtures were similar to previously investigated influenza envelope lipid membranes, which closely mimic the lipid composition of biological membranes. For the investigation of the functional aspects, we employed the human N-Ras protein, which is posttranslationally modified by two lipid modifications that anchor the protein to the membrane. It was previously shown that N-Ras preferentially resides in liquid-disordered domains and exhibits a time-dependent accumulation in the domain boundaries of influenza envelope lipid membranes. For all three model mixtures, we observed the same membrane partitioning behavior for N-Ras. Therefore, we conclude that even relatively simple models of raft membranes are able to reproduce many of their specific properties and functions.
authors: Alexander
authors: A
authors: Vogel
authors: Jörg
authors: J
authors: Nikolaus
authors: Katrin
authors: K
authors: Weise
authors: Gemma
authors: G
authors: Triola
authors: Herbert
authors: H
authors: Waldmann
authors: Roland
authors: R
authors: Winter
authors: Andreas
authors: A
authors: Herrmann
authors: Daniel
authors: D
authors: Huster
mesh_terms: D006801:Humans; D021962:Membrane Microdomains / Q000737:chemistry* / Q000378:metabolism*; D008954:Models, Biological; D016283:Proto-Oncogene Proteins p21(ras) / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*
chemical_list: D016283:Proto-Oncogene Proteins p21(ras)