Eisosomes are large hemitubular structures that underlie the invaginated microdomains in the plasma membrane of various ascomycetous fungi, lichens and unicellular algae. In fungi, they are organized by BAR-domain containing proteins of the Pil1 family. Two such proteins, Pil1 and Lsp1, participate in eisosome formation in the yeast Saccharomyces cerevisiae. Under normal laboratory conditions, deletion of the PIL1 gene results in the inability of cells to assemble wild-type-like eisosomes. We found that under certain stress conditions, Lsp1 partially substitutes for the Pil1 function and mediates assembly of eisosomes, specifically following a decrease in the activity of serine palmitoyltransferase, for example, in response to hyperosmotic stress. Besides Lsp1, the assembly of eisosomes lacking Pil1 also requires Seg1 and Nce102 proteins. Using next-generation sequencing, we found that the seg1Δnce102Δpil1Δ strain, which is unable to form eisosomes, overexpresses genes coding for proteins of oxidative phosphorylation and tricarboxylic acid cycle. By contrast, genes involved in DNA repair, ribosome biogenesis and cell cycle are downregulated. Our results identify Lsp1 as a stress-responsive eisosome organizer and indicate several novel functional connections between the eisosome and essential cellular processes.

• Klíčová slova
• Eisosome, Lsp1, Membrane compartment of Can1, Pil1, Sphingolipid, Stress,
• MeSH
• buněčná membrána metabolismus   MeSH
• fosfoproteiny metabolismus   MeSH
• membránové proteiny metabolismus   MeSH
• Saccharomyces cerevisiae - proteiny * metabolismus   MeSH
• Saccharomyces cerevisiae genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fosfoproteiny MeSH
• LSP1 protein, S cerevisiae MeSH Prohlížeč
• membránové proteiny MeSH
• NCE102 protein, S cerevisiae MeSH Prohlížeč
• PIL1 protein, S cerevisiae MeSH Prohlížeč
• Saccharomyces cerevisiae - proteiny * 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.

• Klíčová slova
• Eisosome, MCC, Membrane microdomain, Plasma 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
• Názvy látek
• cytoskeletální proteiny MeSH
• fosfoproteiny MeSH
• membránové proteiny MeSH
• PIL1 protein, S cerevisiae MeSH Prohlížeč
• Pil1 protein, S pombe MeSH Prohlížeč
• Saccharomyces cerevisiae - proteiny MeSH
• Schizosaccharomyces pombe - proteiny MeSH

We describe a novel mechanism of mRNA decay regulation, which takes place under the conditions of glucose deprivation in the yeast Saccharomyces cerevisiae. The regulation is based on temporally stable sequestration of the main 5'-3' mRNA exoribonuclease Xrn1 at the eisosome, a plasma membrane-associated protein complex organizing a specialized membrane microdomain. As documented by monitoring the decay of a specific mRNA substrate in time, Xrn1-mediated mRNA degradation ceases during the accumulation of Xrn1 at eisosome, but the eisosome-associated Xrn1 retains its functionality and can be re-activated when released to cytoplasm following the addition of glucose. In cells lacking the eisosome organizer Pil1, Xrn1 does not associate with the plasma membrane and its activity is preserved till the stationary phase. Thus, properly assembled eisosome is necessary for this kind of Xrn1 regulation, which occurs in a liquid culture as well as in a differentiated colony.

• Klíčová slova
• Eisosome, Pil1, Plasma membrane compartmentalization, Saccharomyces cerevisiae, Xrn1, mRNA decay regulation,
• MeSH
• buněčná membrána genetika   metabolismus   MeSH
• cytoplazma genetika   metabolismus   MeSH
• exoribonukleasy genetika   metabolismus   MeSH
• fosfoproteiny genetika   metabolismus   MeSH
• membránové mikrodomény genetika   metabolismus   MeSH
• membránové proteiny genetika   metabolismus   MeSH
• messenger RNA metabolismus   MeSH
• multiproteinové komplexy genetika   metabolismus   MeSH
• Saccharomyces cerevisiae - proteiny genetika   metabolismus   MeSH
• Saccharomyces cerevisiae genetika   metabolismus   MeSH
• stabilita RNA genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• exoribonukleasy MeSH
• fosfoproteiny MeSH
• membránové proteiny MeSH
• messenger RNA MeSH
• multiproteinové komplexy MeSH
• PIL1 protein, S cerevisiae MeSH Prohlížeč
• Saccharomyces cerevisiae - proteiny MeSH
• XRN1 protein, S cerevisiae MeSH Prohlížeč

In many eukaryotes, a significant part of the plasma membrane is closely associated with the dynamic meshwork of cortical endoplasmic reticulum (cortical ER). We mapped temporal variations in the local coverage of the yeast plasma membrane with cortical ER pattern and identified micron-sized plasma membrane domains clearly different in cortical ER persistence. We show that clathrin-mediated endocytosis is initiated outside the cortical ER-covered plasma membrane zones. These cortical ER-covered zones are highly dynamic but do not overlap with the immobile and also endocytosis-inactive membrane compartment of Can1 (MCC) and the subjacent eisosomes. The eisosomal component Pil1 is shown to regulate the distribution of cortical ER and thus the accessibility of the plasma membrane for endocytosis.

• MeSH
• buněčná membrána fyziologie   MeSH
• endocytóza * MeSH
• endoplazmatické retikulum fyziologie   MeSH
• fosfoproteiny fyziologie   MeSH
• klathrin fyziologie   MeSH
• Saccharomyces cerevisiae - proteiny fyziologie   MeSH
• Saccharomyces cerevisiae fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fosfoproteiny MeSH
• klathrin MeSH
• PIL1 protein, S cerevisiae MeSH Prohlížeč
• Saccharomyces cerevisiae - proteiny MeSH

The plasma membrane of the fungal pathogen Candida albicans forms a protective barrier that also mediates many processes needed for virulence, including cell wall synthesis, invasive hyphal morphogenesis, and nutrient uptake. Because compartmentalization of the plasma membrane is believed to coordinate these diverse activities, we examined plasma membrane microdomains termed eisosomes or membrane compartment of Can1 (MCC), which correspond to ∼200-nm-long furrows in the plasma membrane. A pil1∆ lsp1∆ mutant failed to form eisosomes and displayed strong defects in plasma membrane organization and morphogenesis, including extensive cell wall invaginations. Mutation of eisosome proteins Slm2, Pkh2, and Pkh3 did not cause similar cell wall defects, although pkh2∆ cells formed chains of furrows and pkh3∆ cells formed wider furrows, identifying novel roles for the Pkh protein kinases in regulating furrows. In contrast, the sur7∆ mutant formed cell wall invaginations similar to those for the pil1∆ lsp1∆ mutant even though it could form eisosomes and furrows. A PH-domain probe revealed that the regulatory lipid phosphatidylinositol 4,5-bisphosphate was enriched at sites of cell wall invaginations in both the sur7∆ and pil1∆ lsp1∆ cells, indicating that this contributes to the defects. The sur7∆ and pil1∆ lsp1∆ mutants displayed differential susceptibility to various types of stress, indicating that they affect overlapping but distinct functions. In support of this, many mutant phenotypes of the pil1∆ lsp1∆ cells were rescued by overexpressing SUR7 These results demonstrate that C. albicans eisosomes promote the ability of Sur7 to regulate plasma membrane organization.

• MeSH
• buněčná membrána metabolismus   MeSH
• buněčná stěna metabolismus   MeSH
• Candida albicans metabolismus   MeSH
• endocytóza fyziologie   MeSH
• fosfoproteiny metabolismus   MeSH
• fungální proteiny metabolismus   MeSH
• hyfy metabolismus   MeSH
• membránové mikrodomény metabolismus   MeSH
• membránové proteiny metabolismus   MeSH
• proteinkinasy metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• fosfoproteiny MeSH
• fungální proteiny MeSH
• membránové proteiny MeSH
• proteinkinasy MeSH

One of the best characterized fungal membrane microdomains is the MCC/eisosome. The MCC (membrane compartment of Can1) is an evolutionarily conserved ergosterol-rich plasma membrane domain. It is stabilized on its cytosolic face by the eisosome, a hemitubular protein complex composed of Bin/Amphiphysin/Rvs (BAR) domain-containing Pil1 and Lsp1. These two proteins bind directly to phosphatidylinositol 4,5-bisphosphate and promote the typical furrow-like shape of the microdomain, with highly curved edges and bottom. While some proteins display stable localization in the MCC/eisosome, others enter or leave it under particular conditions, such as misbalance in membrane lipid composition, changes in membrane tension, or availability of specific nutrients. These findings reveal that the MCC/eisosome, a plasma membrane microdomain with distinct morphology and lipid composition, acts as a multifaceted regulator of various cellular processes including metabolic pathways, cellular morphogenesis, signalling cascades, and mRNA decay. In this minireview, we focus on the MCC/eisosome's proposed role in the regulation of lipid metabolism. While the molecular mechanisms of the MCC/eisosome function are not completely understood, the idea of intracellular processes being regulated at the plasma membrane, the foremost barrier exposed to environmental challenges, is truly exciting.

• Klíčová slova
• MCC, eisosome, ergosterol, lipids, microdomain, phosphoinositides, regulation, sphingolipids,
• MeSH
• buněčná membrána metabolismus   MeSH
• fosfatidylinositol-4,5-difosfát metabolismus   MeSH
• fungální proteiny chemie   metabolismus   MeSH
• homeostáza MeSH
• houby metabolismus   MeSH
• metabolismus lipidů MeSH
• proteinové domény MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• fosfatidylinositol-4,5-difosfát MeSH
• fungální proteiny MeSH

Plasma membrane of the yeast Saccharomyces cerevisiae contains stable lateral domains. We have investigated the ultrastructure of one type of domain, the membrane compartment of Can1 (MCC). In two yeast strains (nce102Delta and pil1Delta) that are defective in segregation of MCC-specific proteins, we found the plasma membrane to be devoid of the characteristic furrow-like invaginations. These are highly conserved plasma membrane structures reported in early freeze-fracture studies. Comparison of the results obtained by three different approaches - electron microscopy of freeze-etched cells, confocal microscopy of intact cells and computer simulation - shows that the number of invaginations corresponds to the number of MCC patches in the membrane of wild-type cells. In addition, neither MCC patches nor the furrow-like invaginations colocalized with the cortical ER. In mutants exhibiting elongated MCC patches, there are elongated invaginations of the appropriate size and frequency. Using various approaches of immunoelectron microscopy, the MCC protein Sur7, as well as the eisosome marker Pil1, have been detected at these invaginations. Thus, we identify the MCC patch, which is a lateral membrane domain of specific composition and function, with a specific structure in the yeast plasma membrane - the furrow-like invagination.

• MeSH
• buněčná membrána metabolismus   ultrastruktura   MeSH
• buněčné výběžky metabolismus   ultrastruktura   MeSH
• endoplazmatické retikulum ultrastruktura   MeSH
• kompartmentace buňky * MeSH
• mutace genetika   MeSH
• počítačová simulace MeSH
• povrchové vlastnosti MeSH
• Saccharomyces cerevisiae - proteiny metabolismus   ultrastruktura   MeSH
• Saccharomyces cerevisiae cytologie   metabolismus   ultrastruktura   MeSH
• transportní systémy pro bazické aminokyseliny metabolismus   MeSH
• zalévání tkání MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• CAN1 protein, S cerevisiae MeSH Prohlížeč
• Saccharomyces cerevisiae - proteiny MeSH
• transportní systémy pro bazické aminokyseliny MeSH

The regulation of gene expression in eukaryotes relies largely on the action of exoribonucleases, evolutionarily conserved enzymes that digest decapped messenger RNAs in the 5'-3' direction. The activity of Xrn1, the major yeast exoribonuclease, is regulated by targeted changes in its cellular localisation in direct response to the cell's metabolic state. When fermentable carbon sources are available, active Xrn1 is diffusely localised in the cytosol. Upon depletion of these sources, Xrn1 is sequestered at the plasma membrane-associated protein complex, the eisosome, and becomes inactive. Although this phenomenon has been described previously, the molecular mechanisms underlying these changes remain unknown. We report that the binding of Xrn1 to the plasma membrane is subject to glycolytic flux, rather than the availability of a fermentable carbon source, is independent of TORC1 activity and requires the core eisosomal proteins Pil1 and Lsp1. We identify the SH3-like domain of the Xrn1 protein as a putative interaction domain. In addition, we show that when expressed in Saccharomyces cerevisiae, the human orthologue of Xrn1 mirrors its yeast counterpart, i.e., it segregates to the eisosome under conditions of halted glycolysis. Our results not only advance our understanding of Xrn1 regulation but also indicate that this regulatory principle is conserved from yeast to humans.

• Klíčová slova
• Eisosome, Exoribonuclease, Glycolysis, SH3-like domain, Xrn1, Yeast,
• Publikační typ
• časopisecké články MeSH

Regulation of gene expression on the level of translation and mRNA turnover is widely conserved evolutionarily. We have found that the main mRNA decay enzyme, exoribonuclease Xrn1, accumulates at the plasma membrane-associated eisosomes after glucose exhaustion in a culture of the yeast S. cerevisiae. Eisosomal localization of Xrn1 is not achieved in cells lacking the main component of eisosomes, Pil1, or Sur7, the protein accumulating at the membrane compartment of Can1 (MCC) - the eisosome-organized plasma membrane microdomain. In contrast to the conditions of diauxic shift, when Xrn1 accumulates in processing bodies (P-bodies), or acute heat stress, in which these cytosolic accumulations of Xrn1 associate with eIF3a/Rpg1-containing stress granules, Xrn1 is not accompanied by other mRNA-decay machinery components when it accumulates at eisosomes in post-diauxic cells. It is important that Xrn1 is released from eisosomes after addition of fermentable substrate. We suggest that this spatial segregation of Xrn1 from the rest of the mRNA-decay machinery reflects a general regulatory mechanism, in which the key enzyme is kept separate from the rest of mRNA decay factors in resting cells but ready for immediate use when fermentable nutrients emerge and appropriate metabolism reprogramming is required. In particular, the localization of Xrn1 to the eisosome, together with previously published data, accents the relevance of this plasma membrane-associated compartment as a multipotent regulatory site.

• MeSH
• buněčná membrána genetika   metabolismus   MeSH
• exoribonukleasy genetika   metabolismus   MeSH
• exprese genu MeSH
• glukosa metabolismus   MeSH
• reakce na tepelný šok MeSH
• rekombinantní fúzní proteiny genetika   metabolismus   MeSH
• reportérové geny MeSH
• Saccharomyces cerevisiae - proteiny genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• exoribonukleasy MeSH
• glukosa MeSH
• rekombinantní fúzní proteiny MeSH
• Saccharomyces cerevisiae - proteiny MeSH
• XRN1 protein, S cerevisiae MeSH Prohlížeč