June 2024

Journal

Neutron spin echo shows pHLIP is capable of retarding membrane thickness fluctuations

By:
Scott, Haden; Burns casamayor, Violeta; Dixson, Andrew; Stanley, Christopher B; Carrillo, Jan Michael Y; Sumpter, Bobby G; Katsaras, John ; Qiang, Wei; Heberle, Frederick; Mertz, Blake; Ashkar, Rana; Barrera, Francisco; Stingaciu, Laura R
Journal Name:
Biochimica et Biophysica Acta (BBA) - Biomembranes
Page Number:
184349
Volume:
1866
Issue Number:
7
Publication Date:
June 20, 2024
View DOI Listing:
https://doi.org/10.1016/j.bbamem.2024.184349

Abstract

Cell membranes are responsible for a range of biological processes that require interactions between lipids and proteins. While the effects of lipids on proteins are becoming better understood, our knowledge of how protein conformational changes influence membrane dynamics remains rudimentary. Here, we performed experiments and computer simulations to study the dynamic response of a lipid membrane to changes in the conformational state of pH-low insertion peptide (pHLIP), which transitions from a surface-associated (SA) state at neutral or basic pH to a transmembrane (TM) α-helix under acidic conditions. Our results show that TM-pHLIP significantly slows down membrane thickness fluctuations due to an increase in effective membrane viscosity. Our findings suggest a possible membrane regulatory mechanism, where the TM helix affects lipid chain conformations, and subsequently alters membrane fluctuations and viscosity.