Lipid fluidity

Huang, L. and A. Haug. 1974. Regulation of membrane lipid fluidity in Acholeplasma laidlawii Effect of carotenoid pigment content. Biochim. Biophys. Acta 352 361-370. 

Mansilla, M.C., Cyhulski, L.E., Albanesi, D. and de Mendoza, D. (2004) Control of membrane lipid fluidity by molecular fhermosensors. Journal of Bacteriology,... 

Golden GM, MvKie JE, Potss RO (1987) Role of stratum comeum lipid fluidity in transdermal drug flux. J Pharm Sci 76 25-28. 

Sinicrope FA, Dudeja PK, Bissonnette BM, et al. Modulation of P-glycoprotein-mediated drug transport by alterations in lipid fluidity of rat liver canalicular membrane vesicles. J Biol Chem 1992 267(35) 24995-25002. 

The modulation of synaptosomal plasma membranes (SPMs) by adriamycin and the resultant effects on the activity of membrane-bound enzymes have been reported [58]. Again DPH was used as fluorescence probe. Adriamycin increased the lipid fluidity of the membrane labeled with DPH, as indicated by the steady-state fluorescence anisotropy. The lipid-phase separation of the membrane at 23.3 °C was perturbed by adriamycin so that the transition temperature was reduced to 16.2 °C. At the same time it was found that the Na+,K+-stimulated ATPase activity exhibits a break point at 22.8 °C in control SPMs. This was reduced to 15.8 °C in adriamydn-treated SPMs. It was proposed that adriamycin achieves this effect through asymmetric perturbation of the lipid membrane structure and that this change in the membrane fluidity may be an early key event in adriamycin-induced neurotoxicity. 

Application of fluid-state PC also initiates biochemical changes in cell cultures. Fluid-state PC increases cellular lipid fluidity and decreases the rate of proliferation of HaCaT human keratinocytes. No toxicity was observed.29 Choline, which is a metabolite of PC and the precursor of the organic osmolyte betaine, is actively transported to the keratinocytes. The relevance of this finding is not understood.30 Acetylcholine is synthesized, secreted, and degraded in human keratinocytes.31 In addition, PLD, which generates choline from PC, is involved in the differentiation of keratinocytes.32... 

Bonnekoh, B., Roding, J., Krueger, G.R. et al. Increase of lipid fluidity and suppression of proliferation resulting from liposome uptake by human keratinocytes in vitro. Br. J. Dermatol. 1991 124 333 10. 

Protein swelling Differential stress due to rapid dehydration Changes in lipid fluidity... 

Long-term surfactant damage to the SC lipid extends from the short-term effects resulting in cumulative loss of barrier function and lipid fluidity leading to profound dryness. The results of an assessment... 

Coupling of maeroseopie and molecular investigations of thermally induced alterations of hairless mouse stratum corneum provide insight into molecular structure and barrier functions of the stratum corneum. Enhanced permeabilities below 70°C have been associated with increased lipid fluidity. However, the keratinized protein component of stratum corneum experiences only minor tertiary structural alterations with thermal pretreatments above 70°C. 

Permeability changes in full-thickness skin have been associated with temperature or solvent pretreatment. The molecular basis of these permeability changes has been attributed to lipid melting or protein conformational changes. The current studies have probed the role of lipid fluidity in the permeability of lipophilic solutes, and examined the effects of temperature on the physical nature of the stratum corneum by differential scanning calorimetry and thermal perturbation infrared spectroscopy. Combining molecular level studies that probe the physical nature of the stratum corneum with permeability results, a correlation between flux of lipophilic solutes and nature of the stratum corneum barrier emerges. 

The potential consequences of the peroxidation of membrane lipids include loss of polyunsaturated fatty acids, decreased lipid fluidity, altered membrane permeability, effects on membrane-associated enzymes, altered ion transport, release of material from subcellular compartments, and the generation of cytotoxic metabolites of lipid hydroperoxides. The physiological significance of lipid peroxidation products is shown in Table 1. 

McElhaney RN. Membrane lipid fluidity, phase state and membrane function in prokaryotic microorganisms. In Membrane Fluidity in Biology, Volume 4. Aloia RA, Boggs JM, eds. 1985. Academic Press, New York. pp. 147-208. 

The passive permeability of lipid membranes is another fluidity related parameter. In general, two mechanisms of membrane permeability can operate in the membrane (8). For many nonpolar molecules, the predominant permeation pathway is solubility-diffusion, which is a combination of partitioning and diffusion across the bilayer, both of which depend on lipid fluidity. In a few cases, such as permeation of positively charged ions through thin bilayers, an alternative pathway prevails (9, 10). It is permeation through transient pores produced in the bilayer by thermal fluctuations. This mechanism, in general, correlates with membrane fluidity. However, for model membranes undergoing the main phase transition, permeation caused by this mechanism exhibits a clear maximum near the phase transition point (11). 

A typical example of an ester acting as a penetration enhancer is isopropyl myristate. Isopropyl myristate might show a double action influence on the partition between vehicles and skin by solubilization and disruption of lipid packing, thus increasing the lipid fluidity... 

Dudeja, P.K. Anderson, K.M. Harris, J.S. Buckingham, L. Coon, J.S. Reversal of multidrug resistance phenotype by surfactants relationship to membrane lipid fluidity. Arch. Biochem. Biophys. 1995, 319 (1), 309-315. 

A major part of the evidence for the participation of the membrane in protein translocation comes from studies of the effects of altered lipid fluidity on secretion. Treatment of E. coli cells with phenethyl alcohol (PEA), which greatly increases membrane fluidity, caused a decrease in secretion of the outer membrane and periplasmic proteins (Pages and Lazdunski, 1981). The amount of protein associated with the inner membrane increased this increase, and the decrease in secretion, were reversible on removal of PEA, suggesting that secretory proteins accumulate at the inner membrane in the presence of the lipid perturbant, but can be secreted and processed when the proper lipid fluidity is restored. [PEA also dissipates proton motive force, which is thought to be required for protein secretion (Daniels et al., 1981) see below.]... 

Thus, protein secretion in E. coli is dramatically affected by the physical state of the membrane lipids. Both increased and decreased fluidity inhibit secretion. It is possible that this effect arises because the signal sequence and/or the secreted protein interact with the membrane lipids, and these interactions are perturbed when the lipid fluidity is changed. However, changes in lipid fluidity also affect other membrane functions such as active transport (DiRienzo and Inouye, 1979). Thus the effect of membrane fluidity on protein secretion may be due to altered activity of a membrane-bound part of the secretory apparatus, and may not be an indication of signal sequence-membrane interaction. 

Benko S, Hilkmann H. Vigh L, van Blitterswijk WJ. Catalytic hydrogenation of fatty acyl chains in plasma membranes effect on membrane lipid fluidity and expression of cell surface antigens. Biochim Biophys Acta 1987 896 129-135. 

Heron D. Shinitzky M, Hershkowitz M, Samuel D. Lipid fluidity markedly modulates the binding of serotonin to mouse brain membranes. Proc Natl Acad Sci USA 1980 77(12) 7463-7467. 

Lenaz, G. (1987). Lipid fluidity and membrane protein dynamics. Bioscience Reports 7,823-837. Loeb, L. A. Gross, R. W. (1986). Identification and purification of sheep platelet phospholipase A2 isofoims. J. Biol. Chem. 261,10467-10470. 

---