scholarly journals Assessing the Role of Lipids in the Molecular Mechanism of Membrane Proteins

2021 ◽  
Vol 22 (14) ◽  
pp. 7267
Author(s):  
Léni Jodaitis ◽  
Thomas van Oene ◽  
Chloé Martens
Keyword(s):  
Membrane Proteins ◽  
Molecular Mechanism ◽  
Protein Interactions ◽  
Protein Function ◽  
Biological Membrane ◽  
Allosteric Coupling ◽  
Lipid Protein Interactions ◽  
Experimental Challenge ◽  
Membrane Protein Function

Membrane proteins have evolved to work optimally within the complex environment of the biological membrane. Consequently, interactions with surrounding lipids are part of their molecular mechanism. Yet, the identification of lipid–protein interactions and the assessment of their molecular role is an experimental challenge. Recently, biophysical approaches have emerged that are compatible with the study of membrane proteins in an environment closer to the biological membrane. These novel approaches revealed specific mechanisms of regulation of membrane protein function. Lipids have been shown to play a role in oligomerization, conformational transitions or allosteric coupling. In this review, we summarize the recent biophysical approaches, or combination thereof, that allow to decipher the role of lipid–protein interactions in the mechanism of membrane proteins.

scholarly journals A general mechanism for drug promiscuity: Studies with amiodarone and other antiarrhythmics

2015 ◽  
Vol 146 (6) ◽  
pp. 463-475 ◽  
Author(s):  
Radda Rusinova ◽  
Roger E. Koeppe ◽  
Olaf S. Andersen
Keyword(s):  
Membrane Proteins ◽  
Lipid Bilayer ◽  
Protein Function ◽  
Single Channel ◽  
General Mechanism ◽  
Antiarrhythmic Agents ◽  
Diverse Range ◽  
Lipid Mixtures ◽  
Membrane Protein Function

Amiodarone is a widely prescribed antiarrhythmic drug used to treat the most prevalent type of arrhythmia, atrial fibrillation (AF). At therapeutic concentrations, amiodarone alters the function of many diverse membrane proteins, which results in complex therapeutic and toxicity profiles. Other antiarrhythmics, such as dronedarone, similarly alter the function of multiple membrane proteins, suggesting that a multipronged mechanism may be beneficial for treating AF, but raising questions about how these antiarrhythmics regulate a diverse range of membrane proteins at similar concentrations. One possible mechanism is that these molecules regulate membrane protein function by altering the common environment provided by the host lipid bilayer. We took advantage of the gramicidin (gA) channels’ sensitivity to changes in bilayer properties to determine whether commonly used antiarrhythmics—amiodarone, dronedarone, propranolol, and pindolol, whose pharmacological modes of action range from multi-target to specific—perturb lipid bilayer properties at therapeutic concentrations. Using a gA-based fluorescence assay, we found that amiodarone and dronedarone are potent bilayer modifiers at therapeutic concentrations; propranolol alters bilayer properties only at supratherapeutic concentration, and pindolol has little effect. Using single-channel electrophysiology, we found that amiodarone and dronedarone, but not propranolol or pindolol, increase bilayer elasticity. The overlap between therapeutic and bilayer-altering concentrations, which is observed also using plasma membrane–like lipid mixtures, underscores the need to explore the role of the bilayer in therapeutic as well as toxic effects of antiarrhythmic agents.

scholarly journals Allostery revealed within lipid binding events to membrane proteins

2018 ◽  
Vol 115 (12) ◽  
pp. 2976-2981 ◽  
Author(s):  
John W. Patrick ◽  
Christopher D. Boone ◽  
Wen Liu ◽  
Gloria M. Conover ◽  
Yang Liu ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Protein Interactions ◽  
Biological Membrane ◽  
Binding Constants ◽  
Native Mass Spectrometry ◽  
Specific Protein ◽  
Lipid Binding ◽  
Allosteric Modulation ◽  
Lipid Species ◽  
Specific Lipid

Membrane proteins interact with a myriad of lipid species in the biological membrane, leading to a bewildering number of possible protein−lipid assemblies. Despite this inherent complexity, the identification of specific protein−lipid interactions and the crucial role of lipids in the folding, structure, and function of membrane proteins is emerging from an increasing number of reports. Fundamental questions remain, however, regarding the ability of specific lipid binding events to membrane proteins to alter remote binding sites for lipids of a different type, a property referred to as allostery [Monod J, Wyman J, Changeux JP (1965)J Mol Biol12:88–118]. Here, we use native mass spectrometry to determine the allosteric nature of heterogeneous lipid binding events to membrane proteins. We monitored individual lipid binding events to the ammonia channel (AmtB) fromEscherichia coli, enabling determination of their equilibrium binding constants. We found that different lipid pairs display a range of allosteric modulation. In particular, the binding of phosphatidylethanolamine and cardiolipin-like molecules to AmtB exhibited the largest degree of allosteric modulation, inspiring us to determine the cocrystal structure of AmtB in this lipid environment. The 2.45-Å resolution structure reveals a cardiolipin-like molecule bound to each subunit of the trimeric complex. Mutation of a single residue in AmtB abolishes the positive allosteric modulation observed for binding phosphatidylethanolamine and cardiolipin-like molecules. Our results demonstrate that specific lipid−protein interactions can act as allosteric modulators for the binding of different lipid types to integral membrane proteins.

scholarly journals Lipid-protein interactions are unique fingerprints for membrane proteins

2017 ◽  
Author(s):  
Valentina Corradi ◽  
Eduardo Mendez-Villuendas ◽  
Helgi I. Ingólfsson ◽  
Ruo-Xu Gu ◽  
Iwona Siuda ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Protein Interactions ◽  
Cell Membranes ◽  
Spatiotemporal Resolution ◽  
Lipid Dynamics ◽  
Lipid Species ◽  
Lipid Environment ◽  
Lipid Protein Interactions ◽  
Dynamics Simulations ◽  
Asymmetrically Distributed

ABSTRACTCell membranes contain hundreds of different proteins and lipids in an asymmetric arrangement. Understanding the lateral organization principles of these complex mixtures is essential for life and health. However, our current understanding of the detailed organization of cell membranes remains rather elusive, owing to the lack of experimental methods suitable for studying these fluctuating nanoscale assemblies of lipids and proteins with the required spatiotemporal resolution. Here, we use molecular dynamics simulations to characterize the lipid environment of ten membrane proteins. To provide a realistic lipid environment, the proteins are embedded in a model plasma membrane, where more than 60 lipid species are represented, asymmetrically distributed between leaflets. The simulations detail how each protein modulates its local lipid environment through local lipid composition, thickness, curvature and lipid dynamics. Our results provide a molecular glimpse of the complexity of lipid-protein interactions, with potentially far reaching implications for the overall organization of the cell membrane.

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