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We report the transmembrane voltage-induced lateral reorganization of highly-ordered lipid microdomains in the plasma membrane of living Saccharomyces cerevisiae. Using trans-parinaric acid (all-trans-9,11,13,15-octadecatetraenoic acid) as a probe of lipid order and different methods of membrane depolarization, we found that depolarization always invokes a significant reduction in the amount of gel-like microdomains in the membrane. Different depolarization mechanisms, including the application of ionophores, cell depolarization by an external electric field, depolarization by proton/hexose co-transport facilitated by HUP1 protein and a reduction of membrane potential caused by compromised respiration efficiency, yielded the same results independently of the yeast strain used. The data suggest that the voltage-induced reorganization of lateral membrane structure could play significant role in fast cellular response to acute stress conditions, as well as in other membrane microdomain-related regulatory mechanisms.
We report sphingolipid-related reorganization of gel-like microdomains in the plasma membrane of living Saccharomyces cerevisiae using trans-Parinaric acid (t-PnA) and 1,6-diphenyl-1,3,5-hexatriene (DPH). Compared to control, the gel-like domains were significantly reduced in the membrane of a sphingolipid-deficient lcb1-100 mutant. The same reduction resulted from sphingolipid depletion by myriocin. The phenotype could be reverted when a myriocin-induced block in sphingolipid biosynthesis was bypassed by exogenous dihydrosphingosine. Lipid order of less-ordered membrane regions decreased with sphingolipid depletion as well, as documented by DPH fluorescence anisotropy. The data indicate that organization of lateral microdomains is an essential physiological role of these structural lipids.
- MeSH
- buněčná membrána chemie metabolismus MeSH
- difenylhexatrien chemie MeSH
- fluorescenční polarizace MeSH
- fluorescenční spektrometrie MeSH
- membránové mikrodomény chemie metabolismus MeSH
- mutace MeSH
- nenasycené mastné kyseliny chemie MeSH
- Saccharomyces cerevisiae MeSH
- sfingolipidy biosyntéza chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Today, it would be difficult for us to live a full life without polymers, especially in medicine, where its applicability is constantly expanding, giving satisfactory results without any harm effects on health. This study focused on the formation of hexagonal domains doped with AgNPs using a KrF excimer laser (λ=248 nm) on the polyetheretherketone (PEEK) surface that acts as an unfailing source of the antibacterial agent - silver. The hexagonal structure was formed with a grid placed in front of the incident laser beam. Surfaces with immobilized silver nanoparticles (AgNPs) were observed by AFM and SEM. Changes in surface chemistry were studied by XPS. To determine the concentration of released Ag+ ions, ICP-MS analysis was used. The antibacterial tests proved the antibacterial efficacy of Ag-doped PEEK composites against Escherichia coli and Staphylococcus aureus as the most common pathogens. Because AgNPs are also known for their strong toxicity, we also included cytotoxicity tests in this study. The findings presented here contribute to the advancement of materials design in the biomedical field, offering a novel starting point for combating bacterial infections through the innovative integration of AgNPs into inert synthetic polymers.
- MeSH
- antibakteriální látky * farmakologie chemie MeSH
- benzofenony * chemie farmakologie MeSH
- biokompatibilní potahované materiály chemie farmakologie MeSH
- Escherichia coli * účinky léků MeSH
- ketony chemie farmakologie MeSH
- kovové nanočástice * chemie MeSH
- lidé MeSH
- mikrobiální testy citlivosti * MeSH
- polyethylenglykoly * chemie farmakologie MeSH
- polymery * chemie farmakologie MeSH
- povrchové vlastnosti MeSH
- Staphylococcus aureus * účinky léků MeSH
- stříbro * chemie farmakologie MeSH
- velikost částic MeSH
- zdravotnické prostředky mikrobiologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
The organization of biological membranes into structurally and functionally distinct lateral microdomains is generally accepted. From bacteria to mammals, laterally compartmentalized membranes seem to be a vital attribute of life. The crucial fraction of our current knowledge about the membrane microdomains has been gained from studies on fungi. In this review we summarize the evidence of the microdomain organization of membranes from fungal cells, with accent on their enormous diversity in composition, temporal dynamics, modes of formation, and recognized engagement in the cell physiology. A special emphasis is laid on the fact that in addition to their other biological functions, membrane microdomains also mediate the communication among different membranes within a eukaryotic cell and coordinate their functions. Involvement of fungal membrane microdomains in stress sensing, regulation of lipid homeostasis, and cell differentiation is discussed more in detail.
Lateral segregation of plasma membrane lipids is a generally accepted phenomenon. Lateral lipid microdomains of specific composition, structure and biological functions are established as a result of simultaneous action of several competing mechanisms which contribute to membrane organization. Various lines of evidence support the conclusion that among those mechanisms, the membrane potential plays significant and to some extent unique role. Above all, clear differences in the microdomain structure as revealed by fluorescence microscopy could be recognized between polarized and depolarized membranes. In addition, recent fluorescence spectroscopy experiments reported depolarization-induced changes in a membrane lipid order. In the context of earlier findings showing that plasma membranes of depolarized cells are less susceptible to detergents and the cells less sensitive to antibiotics or antimycotics treatment we discuss a model, in which membrane potential-driven re-organization of the microdomain structure contributes to maintaining membrane integrity during response to stress, pathogen attack and other challenges involving partial depolarization of the plasma membrane. This article is part of a Special Issue entitled: The cellular lipid landscape edited by Tim P. Levine and Anant K. Menon.
- MeSH
- buněčná membrána metabolismus fyziologie MeSH
- lidé MeSH
- membránové mikrodomény chemie metabolismus fyziologie MeSH
- membránové potenciály fyziologie MeSH
- metabolismus lipidů fyziologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Membrane microdomains denoted commonly as lipid rafts (or membrane rafts) have been implicated in T-cell receptor (TCR), and more generally immunoreceptor, signaling for over 25 years. However, this area of research has been complicated by doubts about the real nature (and even existence) of these membrane entities, especially because of methodological problems connected with possible detergent artefacts. Recent progress in biophysical approaches and functional studies of raft resident proteins apparently clarified many controversial aspects in this area. At present, the prevailing view is that these membrane microdomains are indeed involved in many aspects of cell biology, including immunoreceptor signaling. Moreover, several other types of raft-like microdomains (perhaps better termed nanodomains) have been described, which apparently also play important biological roles.
The existence of specialized microdomains in plasma membranes, postulated for almost 25 years, has been popularized by the concept of lipid or membrane rafts. The idea that detergent-resistant membranes are equivalent to lipid rafts, which was generally abandoned after a decade of vigorous data accumulation, contributed to intense discussions about the validity of the raft concept. The existence of membrane microdomains, meanwhile, has been verified by unequivocal independent evidence. This review summarizes the current state of research in plants and fungi with respect to common aspects of both kingdoms. In these organisms, principally immobile microdomains large enough for microscopic detection have been visualized. These microdomains are found in the context of cell-cell interactions (plant symbionts and pathogens), membrane transport, stress, and polarized growth, and the data corroborate at least three mechanisms of formation. As documented in this review, modern methods of visualization of lateral membrane compartments are also able to uncover the functional relevance of membrane microdomains.
- MeSH
- biologický transport MeSH
- buněčná membrána chemie metabolismus MeSH
- detergenty MeSH
- houby chemie metabolismus MeSH
- membránové mikrodomény chemie metabolismus MeSH
- rostlinné buňky chemie metabolismus MeSH
- rostliny chemie metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
The major brassinosteroid (BR) receptor of Arabidopsis BRASSINOSTEROID INSENSITIVE1 (BRI1) plays fundamental roles in BR signaling, but the molecular mechanisms underlying the effects of BR on BRI1 internalization and assembly state remain unclear. Here, we applied variable angle total internal reflection fluorescence microscopy and fluorescence cross-correlation spectroscopy to analyze the dynamics of GFP-tagged BRI1. We found that, in response to BR, the degree of co-localization of BRI1-GFP with AtFlot1-mCherry increased, and especially BR stimulated the membrane microdomain-associated pathway of BRI1 internalization. We also verified these observations in endocytosis-defective chc2-1 mutants and the AtFlot1 amiRNA 15-5 lines. Furthermore, examination of the phosphorylation status of bri1-EMS-suppressor 1 and measurement of BR-responsive gene expression revealed that membrane microdomains affect BR signaling. These results suggest that BR promotes the partitioning of BRI1 into functional membrane microdomains to activate BR signaling.
- MeSH
- Arabidopsis cytologie metabolismus MeSH
- brassinosteroidy farmakologie MeSH
- časoprostorová analýza * MeSH
- difuze MeSH
- endocytóza účinky léků MeSH
- klathrin metabolismus MeSH
- membránové mikrodomény účinky léků metabolismus MeSH
- multimerizace proteinu účinky léků MeSH
- pohyb těles MeSH
- proteinkinasy metabolismus MeSH
- proteiny huseníčku metabolismus MeSH
- rostlinné buňky účinky léků metabolismus MeSH
- signální transdukce účinky léků MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Eisosomes are plasma membrane-associated protein complexes organizing the membrane compartment of Can1 (MCC), a membrane microdomain of specific structure and function in ascomycetous fungi. By heterologous expression of specific components of Schizosaccharomyces pombe eisosomes in Saccharomyces cerevisiae we reconstitute structures exhibiting the composition and morphology of S. pombe eisosome in the host plasma membrane. We show S. pombe protein Pil1 (SpPil1) to substitute the function of its S. cerevisiae homologue in building plasma membrane-associated assemblies recognized by inherent MCC/eisosome constituents Sur7 and Seg1. Our data indicate that binding of SpPil1 to the plasma membrane of S. cerevisiae also induces formation of furrow-like invaginations characteristic for MCC. To the best of our knowledge, this is the first report of interspecies transfer of a functional plasma membrane microdomain. In the described system, we identify a striking difference between eisosome stabilizer proteins Seg1 and SpSle1. While Seg1 recruits both Pil1 and SpPil1 to the plasma membrane, SpSle1 recognizes only its natural counterpart, SpPil1. In the presence of Pil1, SpSle1 is segregated outside the Pil1-organized eisosomes and forms independent microdomains in the host membrane.
- MeSH
- buněčná membrána metabolismus MeSH
- cytoskeletální proteiny metabolismus MeSH
- fosfoproteiny metabolismus MeSH
- membránové mikrodomény metabolismus MeSH
- membránové proteiny metabolismus MeSH
- Saccharomyces cerevisiae - proteiny metabolismus MeSH
- Saccharomyces cerevisiae metabolismus MeSH
- Schizosaccharomyces pombe - proteiny metabolismus MeSH
- Schizosaccharomyces metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
