Faculty, Staff and Student Publications
Publication Date
7-11-2024
Journal
The Journal of Physical Chemistry B
Abstract
Protein structure has been well established to play a key role in determining function; however, intrinsically disordered proteins and regions (IDPs and IDRs) defy this paradigm. IDPs and IDRs exist as an ensemble of structures rather than a stable 3D structure yet play essential roles in many cell-signaling processes. Nearly all Ras superfamily GTPases are tethered to membranes by a lipid tail at the end of a flexible IDR. The sequence of the IDR is a key determinant of membrane localization, and interaction between the IDR and the membrane has been shown to affect signaling in RAS proteins through the modulation of dynamic membrane organization. Here, we utilized atomistic molecular dynamics simulations to study the membrane interaction, conformational dynamics, and lipid sorting of three IDRs from small GTPases Rheb, RhoA, and DiRas3 in model membranes representing their physiological target membranes. We found that complementarity between the lipidated IDR sequence and target membrane lipid composition is a determinant of conformational plasticity. We also show that electrostatic interactions between anionic lipids and basic residues on IDRs are correlated with sampling of semistable conformational substates, and lack of these interactions is associated with greater conformational diversity. Finally, we show that small GTPase IDRs with a polybasic domain alter local lipid composition by segregating anionic lipids and, in some cases, excluding other lipids from their immediate vicinity in favor of anionic lipids.
Keywords
Humans, Cell Membrane, Intrinsically Disordered Proteins, Lipid Bilayers, Molecular Dynamics Simulation, Monomeric GTP-Binding Proteins, Ras Homolog Enriched in Brain Protein, rhoA GTP-Binding Protein
Included in
Bioinformatics Commons, Biological Phenomena, Cell Phenomena, and Immunity Commons, Biomedical Informatics Commons, Chemical and Pharmacologic Phenomena Commons, Medical Cell Biology Commons, Oncology Commons
Comments
Supplementary Materials
PMID: 38942776