Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 4 complete abstracts (748 words), 10 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
The motion of phospholipid molecules within the lipid bilayer, dependent on the classes of phospholipids present, their fatty acid composition and degree of unsaturation of the acyl chains, the cholesterol concentration, and temperature.
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Fluidities, Membrane; Fluidity, Membrane; Membrane Fluidities; Bilayer Fluidity; Bilayer Fluidities; Fluidities, Bilayer; Fluidity, Bilayer.
Where it fits in the MeSH classification
- Broader topics
- Biophysical Phenomena; Biochemical Phenomena; Cell Physiological Phenomena
Research landscape
PubMed indexes 8,351 records tagged with the MeSH heading “Membrane Fluidity” (counts retrieved 2026-10-29). 412 of them (4.9%) were published from 2020 onward, and the busiest period so far is through 1999 with 4,239 records.
Reviews account for 611 records (7.3%) and meta-analyses for 1. Randomized controlled trials number 22 (0.3%) as a share of all records on the topic. Randomized trials make up only a small share of this literature, so much of what is known comes from laboratory, observational or descriptive work.
Show the data
| Period | Records |
|---|---|
| through 1999 | 4,239 |
| 2000-2009 | 2,311 |
| 2010-2019 | 1,389 |
| 2020 onward | 412 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 611 | 7.3% |
| Meta-analyses | 1 | 0.0% |
| Randomized controlled trials | 22 | 0.3% |
Method: PubMed query "Membrane Fluidity"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-29.
Reading the evidence in molecular biology
Molecular biology establishes mechanisms through controlled experiments, often in simplified systems such as purified proteins, cultured cells or model organisms. Such work can show what is possible in a defined system, but whether a pathway matters in a whole organism or in human disease needs further evidence. Check the experimental system, whether findings were reproduced by independent groups, and whether the authors tested the mechanism directly or inferred it from correlation.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Control of membrane fusion mechanism by lipid composition: predictions from ensemble molecular dynamics | 2007 | Research article Design not recorded in structured metadata | 109 | cc by PMID 18020701 · DOI · PMC2077900 |
| Low membrane fluidity triggers lipid phase separation and protein segregation in living bacteria | 2022 | Research article Design not recorded in structured metadata | 103 | cc by PMID 35037270 · DOI · PMC8886542 |
| Antimicrobial peptide cWFW kills by combining lipid phase separation with autolysis | 2017 | Research article Design not recorded in structured metadata | 103 | cc by PMID 28276520 · DOI · PMC5343580 |
| ATP-driven membrane binding and polymerization of bacterial actin MreB promotes local membrane fluidization | 2026 | Research article Design not recorded in structured metadata | 1 | cc by PMID 42237545 · DOI · PMC13507481 |
Control of membrane fusion mechanism by lipid composition: predictions from ensemble molecular dynamics [1]
Abstract reading summary — source excerpts
- Opening excerpt
- Membrane fusion is critical to biological processes such as viral infection, endocrine hormone secretion, and neurotransmission, yet the precise mechanistic details of the fusion process remain unknown.
- Closing excerpt
- These predicted effects of lipid composition on fusion mechanism both underscore the way in which experimental model system construction may affect the observed mechanism of fusion and illustrate a potential mechanism for cellular regulation of the fusion process by altering membrane composition.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (231 words)
Membrane fusion is critical to biological processes such as viral infection, endocrine hormone secretion, and neurotransmission, yet the precise mechanistic details of the fusion process remain unknown. Current experimental and computational model systems approximate the complex physiological membrane environment for fusion using one or a few protein and lipid species. Here, we report results of a computational model system for fusion in which the ratio of lipid components was systematically varied, using thousands of simulations of up to a microsecond in length to predict the effects of lipid composition on both fusion kinetics and mechanism. In our simulations, increased phosphatidylcholine content in vesicles causes increased activation energies for formation of the initial stalk-like intermediate for fusion and of hemifusion intermediates, in accordance with previous continuum-mechanics theoretical treatments. We also use our large simulation dataset to quantitatively compare the mechanism by which vesicles fuse at different lipid compositions, showing a significant difference in fusion kinetics and mechanism at different compositions simulated. As physiological membranes have different compositions in the inner and outer leaflets, we examine the effect of such asymmetry, as well as the effect of membrane curvature on fusion. These predicted effects of lipid composition on fusion mechanism both underscore the way in which experimental model system construction may affect the observed mechanism of fusion and illustrate a potential mechanism for cellular regulation of the fusion process by altering membrane composition.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 18020701 · DOI · PMC2077900
Low membrane fluidity triggers lipid phase separation and protein segregation in living bacteria [2]
Abstract reading summary — source excerpts
- Opening excerpt
- All living organisms adapt their membrane lipid composition in response to changes in their environment or diet.
- Closing excerpt
- Importantly, the in vivo lipid phase separation is not associated with a breakdown of the membrane diffusion barrier function, thus explaining why the phase separation process induced by low fluidity is biologically reversible.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (176 words)
All living organisms adapt their membrane lipid composition in response to changes in their environment or diet. These conserved membrane-adaptive processes have been studied extensively. However, key concepts of membrane biology linked to regulation of lipid composition including homeoviscous adaptation maintaining stable levels of membrane fluidity, and gel-fluid phase separation resulting in domain formation, heavily rely upon in vitro studies with model membranes or lipid extracts. Using the bacterial model organisms Escherichia coli and Bacillus subtilis, we now show that inadequate in vivo membrane fluidity interferes with essential complex cellular processes including cytokinesis, envelope expansion, chromosome replication/segregation and maintenance of membrane potential. Furthermore, we demonstrate that very low membrane fluidity is indeed capable of triggering large-scale lipid phase separation and protein segregation in intact, protein-crowded membranes of living cells; a process that coincides with the minimal level of fluidity capable of supporting growth. Importantly, the in vivo lipid phase separation is not associated with a breakdown of the membrane diffusion barrier function, thus explaining why the phase separation process induced by low fluidity is biologically reversible.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 35037270 · DOI · PMC8886542
Antimicrobial peptide cWFW kills by combining lipid phase separation with autolysis [3]
Abstract reading summary — source excerpts
- Opening excerpt
- The synthetic cyclic hexapeptide cWFW (cyclo(RRRWFW)) has a rapid bactericidal activity against both Gram-positive and Gram-negative bacteria.
- Closing excerpt
- This novel antibacterial mode of action holds a low risk to induce bacterial resistance, and provides valuable information for the design of new synthetic antimicrobial peptides.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (150 words)
The synthetic cyclic hexapeptide cWFW (cyclo(RRRWFW)) has a rapid bactericidal activity against both Gram-positive and Gram-negative bacteria. Its detailed mode of action has, however, remained elusive. In contrast to most antimicrobial peptides, cWFW neither permeabilizes the membrane nor translocates to the cytoplasm. Using a combination of proteome analysis, fluorescence microscopy, and membrane analysis we show that cWFW instead triggers a rapid reduction of membrane fluidity both in live Bacillus subtilis cells and in model membranes. This immediate activity is accompanied by formation of distinct membrane domains which differ in local membrane fluidity, and which severely disrupts membrane protein organisation by segregating peripheral and integral proteins into domains of different rigidity. These major membrane disturbances cause specific inhibition of cell wall synthesis, and trigger autolysis. This novel antibacterial mode of action holds a low risk to induce bacterial resistance, and provides valuable information for the design of new synthetic antimicrobial peptides.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 28276520 · DOI · PMC5343580
ATP-driven membrane binding and polymerization of bacterial actin MreB promotes local membrane fluidization [4]
Abstract reading summary — source excerpts
- Opening excerpt
- The bacterial actin homolog MreB plays a key role in rod cell shape determination.
- Closing excerpt
- We also show that monomeric MreBGs establishes peripheral contacts with the membrane likely through electrostatic interactions, while Mg⋅ATP-induced MreBGs filaments insert into the lipid bilayer without interfering with the membrane lamellar phase and have a significant local fluidifying effect.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (191 words)
The bacterial actin homolog MreB plays a key role in rod cell shape determination. We recently showed that MreB from the Gram-positive bacterium Geobacillus stearothermophilus (MreBGs) polymerizes into straight pairs of protofilaments in the presence of both ATP and a lipid surface. Membrane interaction is thought to be mediated by electrostatic interactions with anionic lipids, with final anchoring relying on two spatially close hydrophobic motifs that protrude from the MreBGs monomers, forming a putative membrane-insertion domain. Here, we determined the binding properties of ATP and ADP to MreBGs using fluorescence anisotropy and monitored ATP-mediated binding and polymer formation on lipid bilayers using liposome-binding assays and atomic force microscopy, respectively. Finally, we used solid-state NMR to visualize the interaction between the membrane and MreBGs at the atomic level. Our findings reveal that divalent cations are required for nucleotide binding and that, unlike eukaryotic actin, MreBGs has similar affinity for both ATP and ADP. We also show that monomeric MreBGs establishes peripheral contacts with the membrane likely through electrostatic interactions, while Mg⋅ATP-induced MreBGs filaments insert into the lipid bilayer without interfering with the membrane lamellar phase and have a significant local fluidifying effect.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42237545 · DOI · PMC13507481
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article Fluidity parameters of lipid regions determined by fluorescence polarization [5]
- Research article Model systems, lipid rafts, and cell membranes [6]
- Research article Single-particle tracking: applications to membrane dynamics [7]
- Research article The modification of mammalian membrane polyunsaturated fatty acid composition in relation to membrane fluidity and function [8]
- Research article Thermal adaptation in biological membranes: is homeoviscous adaptation the explanation? [9]
- Research article Phospholipid methylation and biological signal transmission [10]
References
- Kasson PM, Pande VS. Control of membrane fusion mechanism by lipid composition: predictions from ensemble molecular dynamics. . 2007. PMID 18020701 · DOI · PMC2077900
- Gohrbandt M, Lipski A, Grimshaw JW, Buttress JA, Baig Z, Herkenhoff B, et al.. Low membrane fluidity triggers lipid phase separation and protein segregation in living bacteria. . 2022. PMID 35037270 · DOI · PMC8886542
- Scheinpflug K, Wenzel M, Krylova O, Bandow JE, Dathe M, Strahl H. Antimicrobial peptide cWFW kills by combining lipid phase separation with autolysis. . 2017. PMID 28276520 · DOI · PMC5343580
- Adriaans IE, Álvarez-Mena A, Dinet C, Morvan E, Lim KS, Dufourc EJ, et al.. ATP-driven membrane binding and polymerization of bacterial actin MreB promotes local membrane fluidization. . 2026. PMID 42237545 · DOI · PMC13507481
- Shinitzky M, Barenholz Y. Fluidity parameters of lipid regions determined by fluorescence polarization. Biochim Biophys Acta. 1978. PMID 365237 · DOI
- Simons K, Vaz WL. Model systems, lipid rafts, and cell membranes. Annu Rev Biophys Biomol Struct. 2004. PMID 15139814 · DOI
- Saxton MJ, Jacobson K. Single-particle tracking: applications to membrane dynamics. Annu Rev Biophys Biomol Struct. 1997. PMID 9241424 · DOI
- Stubbs CD, Smith AD. The modification of mammalian membrane polyunsaturated fatty acid composition in relation to membrane fluidity and function. Biochim Biophys Acta. 1984. PMID 6229284 · DOI
- Hazel JR. Thermal adaptation in biological membranes: is homeoviscous adaptation the explanation?. Annu Rev Physiol. 1995. PMID 7778864 · DOI
- Hirata F, Axelrod J. Phospholipid methylation and biological signal transmission. Science. 1980. PMID 6157192 · DOI
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-29.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.