pH sensing by lipids in membranes: The fundamentals of pH-driven migration, polarization and deformations of lipid bilayer assemblies

• Published in: Biochimica et biophysica acta. Biomembranes 2018-10, Vol.1860 (10), p.2042-2063
• Main Authors: Angelova, Miglena I., Bitbol, Anne-Florence, Seigneuret, Michel, Staneva, Galya, Kodama, Atsuji, Sakuma, Yuka, Kawakatsu, Toshihiro, Imai, Masayuki, Puff, Nicolas
• Format: Article
• Language: English
• Subjects: Alzheimer's disease; Biological Physics; Giant unilamellar vesicle; Lipid membrane dynamics; Local chemical gradient; Local chemical modification; Mitochondria; Physics
• ISSN: 0005-2736; 1879-2642
• DOI: 10.1016/j.bbamem.2018.02.026

Most biological molecules contain acido-basic groups that modulate their structure and interactions. A consequence is that pH gradients, local heterogeneities and dynamic variations are used by cells and organisms to drive or regulate specific biological functions including energetic metabolism, vesicular traffic, migration and spatial patterning of tissues in development. While the direct or regulatory role of pH in protein function is well documented, the role of hydrogen and hydroxyl ions in modulating the properties of lipid assemblies such as bilayer membranes is only beginning to be understood. Here, we review approaches using artificial lipid vesicles that have been instrumental in providing an understanding of the influence of pH gradients and local variations on membrane vectorial motional processes: migration, membrane curvature effects promoting global or local deformations, crowding generation by segregative polarization processes. In the case of pH induced local deformations, an extensive theoretical framework is given and an application to a specific biological issue, namely the structure and stability of mitochondrial cristae, is described. This article is part of a Special Issue entitled: Emergence of Complex Behavior in Biomembranes edited by Marjorie Longo. [Display omitted] •Membrane lipids are directly affected by pH, due to their acido-basic properties.•pH change can induce lipid vesicle migration and global deformation.•pH change can cause polarization in phase-separated membrane of GUVs.•Localized pH heterogeneities can induce local dynamical membrane deformations.•Mitochondrial cristae formation has been mimicked using lipid-only systems.