The absence of Isc1, the yeast homologue of mammalian neutral sphingomyelinase type 2, leads to severe mitochondrial dysfunction. We show that the deletion of another type C phospholipase, the phosphatidylglycerol (PG)-specific phospholipase Pgc1, rescues this defect. Phosphatidylethanolamine (PE) levels and cytochrome c oxidase activity, which were reduced in isc1Δ cells, were restored to wild-type levels in the pgc1Δ isc1Δ mutant. The Pgc1 substrate PG inhibited the in vitro activities of Isc1 and the phosphatidylserine decarboxylase Psd1, an enzyme crucial for PE biosynthesis. We also identify a mechanism by which the balance between the current demand for PG and its consumption is controlled. We document that the product of PG hydrolysis, diacylglycerol, competes with the substrate of PG-phosphate synthase, Pgs1, and thereby inhibits the biosynthesis of excess PG. This feedback loop does not work in the absence of Pgc1, which catalyzes PG degradation. Finally, Pgc1 activity is partially inhibited by products of Isc1-mediated hydrolysis. The described functional interconnection of the two phospholipases contributes significantly to lipid homeostasis throughout the cellular architecture. IMPORTANCE In eukaryotic cells, mitochondria are constantly adapting to changes in the biological activity of the cell, i.e., changes in nutrient availability and environmental stresses. We propose a model in which this adaptation is mediated by lipids. Specifically, we show that mitochondrial phospholipids regulate the biosynthesis of cellular sphingolipids and vice versa. To do this, lipids move by free diffusion, which does not require energy and works under any condition. This model represents a simple way for the cell to coordinate mitochondrial structure and performance with the actual needs of overall cellular metabolism. Its simplicity makes it a universally applicable principle of cellular regulation.

• Klíčová slova
• ceramide, diacylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phospholipase C, respiration,
• MeSH
• fosfatidylglyceroly metabolismus   MeSH
• fosfolipasy typu C * metabolismus   MeSH
• fosfolipasy chemie   metabolismus   MeSH
• mitochondrie metabolismus   MeSH
• Saccharomyces cerevisiae - proteiny * genetika   metabolismus   MeSH
• Saccharomyces cerevisiae metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fosfatidylglyceroly MeSH
• fosfolipasy typu C * MeSH
• fosfolipasy MeSH
• ISC1 protein, S cerevisiae MeSH Prohlížeč
• Saccharomyces cerevisiae - proteiny * MeSH

Barth syndrome (BTHS) is an inherited mitochondrial disorder characterized by a decrease in total cardiolipin and the accumulation of its precursor monolysocardiolipin due to the loss of the transacylase enzyme tafazzin. However, the molecular basis of BTHS pathology is still not well understood. Here we characterize the double mutant pgc1Δtaz1Δ of Saccharomyces cerevisiae deficient in phosphatidylglycerol-specific phospholipase C and tafazzin as a new yeast model of BTHS. Unlike the taz1Δ mutant used to date, this model accumulates phosphatidylglycerol, thus better approximating the human BTHS cells. We demonstrate that increased phosphatidylglycerol in this strain leads to more pronounced mitochondrial respiratory defects and an increased incidence of aberrant mitochondria compared to the single taz1Δ mutant. We also show that the mitochondria of the pgc1Δtaz1Δ mutant exhibit a reduced rate of respiration due to decreased cytochrome c oxidase and ATP synthase activities. Finally, we determined that the mood-stabilizing anticonvulsant valproic acid has a positive effect on both lipid composition and mitochondrial function in these yeast BTHS models. Overall, our results show that the pgc1Δtaz1Δ mutant better mimics the cellular phenotype of BTHS patients than taz1Δ cells, both in terms of lipid composition and the degree of disruption of mitochondrial structure and function. This favors the new model for use in future studies.

• Klíčová slova
• Barth syndrome, mitochondria, phosphatidylglycerol, tafazzin, valproic acid,
• MeSH
• acyltransferasy metabolismus   MeSH
• Barthův syndrom * metabolismus   MeSH
• fenotyp MeSH
• fosfatidylglyceroly * antagonisté a inhibitory   metabolismus   MeSH
• kardiolipiny * genetika   metabolismus   MeSH
• lidé MeSH
• Saccharomyces cerevisiae metabolismus   MeSH
• transkripční faktory metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• acyltransferasy MeSH
• fosfatidylglyceroly * MeSH
• kardiolipiny * MeSH
• TAFAZZIN protein, human MeSH Prohlížeč
• transkripční faktory MeSH

The strain Raoultella sp. KDF8 was cultivated on three sources of carbon and energy, glycerol, ethanol and diclofenac, for periods of time ranging from 24 to 72 h. Using thin-layer chromatography, nine classes of phospholipids were detected and the amount of phosphatidylethanolamine (PtdEtn) decreased with increasing cultivation time. Conversely, the ratio of phospholipids having three or four acyls (acyl-phosphatidylglycerol (APtdGro), N-acyl-PtdEtn (NAPtdEtn) and cardiolipin (Ptd2Gro) increased during cultivation. GC-MS analysis showed that the percentage of fatty acids containing a cyclopropane ring increased almost tenfold whereas the amount of fatty acids bearing even-numbered chains dropped to less than one-third after 24 h and 72 h in cultures on glycerol and diclofenac, respectively. Shotgun analysis showed significant changes in the representation of molecular species of phospholipids. For instance, there was a 36-fold change in the ratio of 16:1/16:1/16:1-APtdGro to c17:0/c17:0/c17:0-APtdGro and a 12-fold ratio change for 16:1/16:1/16:1-NAPtdEtn to c17:0/c17:0/c17:0-NAPtdEtn; the Ptd2Gro ratio of 16:1 to c17:0 acids equalled 1750. Our results show that the bacteria overcome destabilization of the inner cytoplasmic cell membrane and a bacterial outer membrane by altering the geometric arrangement of acyl chains, i.e. switching from monounsaturated to cyclopropane fatty acids (16:1 versus c17:0).

• MeSH
• antiflogistika farmakologie   MeSH
• buněčná membrána účinky léků   metabolismus   MeSH
• diklofenak farmakologie   MeSH
• Enterobacteriaceae účinky léků   metabolismus   MeSH
• fosfatidylethanolaminy chemie   metabolismus   MeSH
• fosfatidylglyceroly chemie   metabolismus   MeSH
• fosfolipidy chemie   metabolismus   MeSH
• lipidomika MeSH
• mastné kyseliny chemie   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antiflogistika MeSH
• diklofenak MeSH
• fosfatidylethanolaminy MeSH
• fosfatidylglyceroly MeSH
• fosfolipidy MeSH
• mastné kyseliny MeSH
• N-acylphosphatidylethanolamine MeSH Prohlížeč

The biosynthesis of yeast phosphatidylglycerol (PG) takes place in the inner mitochondrial membrane. Outside mitochondria, the abundance of PG is low. Here, we present evidence that the subcellular distribution of PG is maintained by the locally controlled enzymatic activity of the PG-specific phospholipase, Pgc1. A fluorescently labeled Pgc1 protein accumulates on the surface of lipid droplets (LD). We show, however, that LD are not only dispensable for Pgc1-mediated PG degradation, but do not even host any phospholipase activity of Pgc1. Our in vitro assays document the capability of LD-accumulated Pgc1 to degrade PG upon entry to the membranes of the endoplasmic reticulum, mitochondria and even of artificial phospholipid vesicles. Fluorescence recovery after photobleaching analysis confirms the continuous exchange of GFP-Pgc1 within the individual LD in situ, suggesting that a steady-state equilibrium exists between LD and membranes to regulate the immediate phospholipase activity of Pgc1. In this model, LD serve as a storage place and shelter Pgc1, preventing its untimely degradation, while both phospholipase activity and degradation of the enzyme occur in the membranes.

• Klíčová slova
• Pgc1, lipid degradation, lipid droplets, phosphatidylglycerol, yeast,
• MeSH
• endoplazmatické retikulum metabolismus   MeSH
• fosfatidylglyceroly metabolismus   MeSH
• fosfolipasy typu C metabolismus   MeSH
• homeostáza MeSH
• lipidová tělíska chemie   MeSH
• metabolismus lipidů MeSH
• mitochondrie metabolismus   MeSH
• Saccharomyces cerevisiae - proteiny genetika   metabolismus   MeSH
• Saccharomyces cerevisiae enzymologie   genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fosfatidylglyceroly MeSH
• fosfolipasy typu C MeSH
• Saccharomyces cerevisiae - proteiny MeSH

Understanding the molecular mechanisms governing nanoparticle-membrane interactions is of prime importance for drug delivery and biomedical applications. Neutron reflectometry (NR) experiments are combined with atomistic and coarse-grained molecular dynamics (MD) simulations to study the interaction between cationic gold nanoparticles (AuNPs) and model lipid membranes composed of a mixture of zwitterionic di-stearoyl-phosphatidylcholine (DSPC) and anionic di-stearoyl-phosphatidylglycerol (DSPG). MD simulations show that the interaction between AuNPs and a pure DSPC lipid bilayer is modulated by a free energy barrier. This can be overcome by increasing temperature, which promotes an irreversible AuNP incorporation into the lipid bilayer. NR experiments confirm the encapsulation of the AuNPs within the lipid bilayer at temperatures around 55 °C. In contrast, the AuNP adsorption is weak and impaired by heating for a DSPC-DSPG (3:1) lipid bilayer. These results demonstrate that both the lipid charge and the temperature play pivotal roles in AuNP-membrane interactions. Furthermore, NR experiments indicate that the (negative) DSPG lipids are associated with lipid extraction upon AuNP adsorption, which is confirmed by coarse-grained MD simulations as a lipid-crawling effect driving further AuNP aggregation. Overall, the obtained detailed molecular view of the interaction mechanisms sheds light on AuNP incorporation and membrane destabilization.

• Klíčová slova
• gold nanoparticles, lipid membranes, molecular dynamics simulations, nanotoxicity, neutron reflectometry,
• MeSH
• adsorpce MeSH
• biologický transport MeSH
• fosfatidylcholiny chemie   metabolismus   MeSH
• fosfatidylglyceroly chemie   metabolismus   MeSH
• hydrofobní a hydrofilní interakce MeSH
• kationty chemie   farmakokinetika   MeSH
• kovové nanočástice * chemie   MeSH
• lipidové dvojvrstvy chemie   metabolismus   MeSH
• membránové lipidy chemie   metabolismus   MeSH
• povrchové vlastnosti MeSH
• simulace molekulární dynamiky MeSH
• teplota * MeSH
• zlato chemie   farmakokinetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fosfatidylcholiny MeSH
• fosfatidylglyceroly MeSH
• kationty MeSH
• lipidové dvojvrstvy MeSH
• membránové lipidy MeSH
• zlato MeSH

Phosphatidylglycerol is an essential phospholipid for photosynthesis and other cellular processes. We investigated the role of phosphatidylglycerol in cell division and metabolism in a phophatidylglycerol-auxotrophic strain of Synechococcus PCC7942. Here we show that phosphatidylglycerol is essential for the photosynthetic electron transfer and for the oligomerisation of the photosynthetic complexes, notably, we revealed that this lipid is important for non-linear electron transport. Furthermore, we demonstrate that phosphatidylglycerol starvation elevated the expressions of proteins of nitrogen and carbon metabolism. Moreover, we show that phosphatidylglycerol-deficient cells changed the morphology, became elongated, the FtsZ ring did not assemble correctly, and subsequently the division was hindered. However, supplementation with phosphatidylglycerol restored the ring-like structure at the mid-cell region and the normal cell size, demonstrating the phosphatidylglycerol is needed for normal septum formation. Taken together, central roles of phosphatidylglycerol were revealed; it is implicated in the photosynthetic activity, the metabolism and the fission of bacteria.

• Klíčová slova
• Division, Electron transport, Lipid, Phosphatidylglycerol, Photosynthesis,
• MeSH
• buněčné dělení * MeSH
• fosfatidylglyceroly metabolismus   MeSH
• fotosystém I - proteinový komplex metabolismus   MeSH
• Synechococcus fyziologie   MeSH
• transport elektronů MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• fosfatidylglyceroly MeSH
• fotosystém I - proteinový komplex MeSH

In yeast, phosphatidylglycerol (PG) is a minor phospholipid under standard conditions; it can be utilized for cardiolipin (CL) biosynthesis by CL synthase, Crd1p, or alternatively degraded by the phospholipase Pgc1p. The Saccharomyces cerevisiae deletion mutants crd1Δ and pgc1Δ both accumulate PG. Based on analyses of the phospholipid content of pgc1Δ and crd1Δ yeast, we revealed that in yeast mitochondria, two separate pools of PG are present, which differ in their fatty acid composition and accessibility for Pgc1p-catalyzed degradation. In contrast to CL-deficient crd1Δ yeast, the pgc1Δ mutant contains normal levels of CL. This makes the pgc1Δ strain a suitable model to study the effect of accumulation of PG per se. Using fluorescence microscopy, we show that accumulation of PG with normal levels of CL resulted in increased fragmentation of mitochondria, while in the absence of CL, accumulation of PG led to the formation of large mitochondrial sheets. We also show that pgc1Δ mitochondria exhibited increased respiration rates due to increased activity of cytochrome c oxidase. Taken together, our results indicate that not only a lack of anionic phospholipids, but also excess PG, or unbalanced ratios of anionic phospholipids in mitochondrial membranes, have harmful consequences on mitochondrial morphology and function.

• Klíčová slova
• Mitochondria, Morphology, Phosphatidylglycerol, Respiration, Yeast,
• MeSH
• fosfatidylglyceroly metabolismus   MeSH
• fosfolipasy fyziologie   MeSH
• kardiolipiny biosyntéza   MeSH
• mitochondrie metabolismus   ultrastruktura   MeSH
• respirační komplex IV metabolismus   MeSH
• Saccharomyces cerevisiae metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• fosfatidylglyceroly MeSH
• fosfolipasy MeSH
• kardiolipiny MeSH
• respirační komplex IV MeSH

The negatively charged lipid phosphatidylglycerol (PG) constitutes up to 10% of total lipids in photosynthetic membranes, and its deprivation in cyanobacteria is accompanied by chlorophyll (Chl) depletion. Indeed, radioactive labeling of the PG-depleted ΔpgsA mutant of Synechocystis sp. strain PCC 6803, which is not able to synthesize PG, proved the inhibition of Chl biosynthesis caused by restriction on the formation of 5-aminolevulinic acid and protochlorophyllide. Although the mutant accumulated chlorophyllide, the last Chl precursor, we showed that it originated from dephytylation of existing Chl and not from the block in the Chl biosynthesis. The lack of de novo-produced Chl under PG depletion was accompanied by a significantly weakened biosynthesis of both monomeric and trimeric photosystem I (PSI) complexes, although the decrease in cellular content was manifested only for the trimeric form. However, our analysis of ΔpgsA mutant, which lacked trimeric PSI because of the absence of the PsaL subunit, suggested that the virtual stability of monomeric PSI is a result of disintegration of PSI trimers. Interestingly, the loss of trimeric PSI was accompanied by accumulation of monomeric PSI associated with the newly synthesized CP43 subunit of photosystem II. We conclude that the absence of PG results in the inhibition of Chl biosynthetic pathway, which impairs synthesis of PSI, despite the accumulation of chlorophyllide released from the degraded Chl proteins. Based on the knowledge about the role of PG in prokaryotes, we hypothesize that the synthesis of Chl and PSI complexes are colocated in a membrane microdomain requiring PG for integrity.

• MeSH
• bakteriální proteiny genetika   metabolismus   MeSH
• chlorofyl biosyntéza   metabolismus   MeSH
• chlorofylidy metabolismus   MeSH
• fosfatidylglyceroly genetika   metabolismus   MeSH
• fotosystém I - proteinový komplex metabolismus   MeSH
• ligasy tvořící vazby C-O metabolismus   MeSH
• protochlorofylid metabolismus   MeSH
• světlosběrné proteinové komplexy metabolismus   MeSH
• Synechocystis genetika   metabolismus   MeSH
• transferasy pro jiné substituované fosfátové skupiny genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• bakteriální proteiny MeSH
• CDP-diacylglycerol-glycerol-3-phosphate 3-phosphatidyltransferase MeSH Prohlížeč
• chlorofyl MeSH
• chlorofylidy MeSH
• chlorophyll A binding protein CP43, Cyanobacteria MeSH Prohlížeč
• chlorophyll synthetase MeSH Prohlížeč
• fosfatidylglyceroly MeSH
• fotosystém I - proteinový komplex MeSH
• ligasy tvořící vazby C-O MeSH
• protochlorofylid MeSH
• světlosběrné proteinové komplexy MeSH
• transferasy pro jiné substituované fosfátové skupiny MeSH

The influence of maltose-modified poly(propylene imine) (PPI) dendrimers on dimyristoylphosphatidylcholine (DMPC) or dimyristoylphosphatidylcholine/dimyristoylphosphatidylglycerol (DMPC/DMPG) (3%) liposomes was studied. Fourth generation (G4) PPI dendrimers with primary amino surface groups were partially (open shell glycodendrimers - OS) or completely (dense shell glycodendrimers - DS) modified with maltose residues. As a model membrane, two types of 100nm diameter liposomes were used to observe differences in the interactions between neutral DMPC and negatively charged DMPC/DMPG bilayers. Interactions were studied using fluorescence spectroscopy to evaluate the membrane fluidity of both the hydrophobic and hydrophilic parts of the lipid bilayer and using differential scanning calorimetry to investigate thermodynamic parameter changes. Pulsed-filed gradient NMR experiments were carried out to evaluate common diffusion coefficient of DMPG and DS PPI in D2O when using below critical micelle concentration of DMPG. Both OS and DS PPI G4 dendrimers show interactions with liposomes. Neutral DS dendrimers exhibit stronger changes in membrane fluidity compared to OS dendrimers. The bilayer structure seems more rigid in the case of anionic DMPC/DMPG liposomes in comparison to pure and neutral DMPC liposomes. Generally, interactions of dendrimers with anionic DMPC/DMPG and neutral DMPC liposomes were at the same level. Higher concentrations of positively charged OS dendrimers induced the aggregation process with negatively charged liposomes. For all types of experiments, the presence of NaCl decreased the strength of the interactions between glycodendrimers and liposomes. Based on NMR diffusion experiments we suggest that apart from electrostatic interactions for OS PPI hydrogen bonds play a major role in maltose-modified PPI dendrimer interactions with anionic and neutral model membranes where a contact surface is needed for undergoing multiple H-bond interactions between maltose shell of glycodendrimers and surface membrane of liposome.

• Klíčová slova
• Glycodendrimer, Hydrogen bond, Ionic force, Liposomes, Model membranes,
• MeSH
• dendrimery chemie   metabolismus   MeSH
• difenylhexatrien chemie   MeSH
• diferenciální skenovací kalorimetrie MeSH
• dimyristoylfosfatidylcholin chemie   metabolismus   MeSH
• fluidita membrány MeSH
• fluorescenční polarizace MeSH
• fosfatidylglyceroly chemie   metabolismus   MeSH
• hydrofobní a hydrofilní interakce MeSH
• lipidové dvojvrstvy chemie   metabolismus   MeSH
• liposomy chemie   metabolismus   MeSH
• magnetická rezonanční spektroskopie MeSH
• maltosa chemie   metabolismus   MeSH
• membránové lipidy chemie   metabolismus   MeSH
• polypropyleny chemie   metabolismus   MeSH
• statická elektřina MeSH
• vodíková vazba MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• dendrimery MeSH
• difenylhexatrien MeSH
• dimyristoylfosfatidylcholin MeSH
• dimyristoylphosphatidylglycerol MeSH Prohlížeč
• fosfatidylglyceroly MeSH
• lipidové dvojvrstvy MeSH
• liposomy MeSH
• maltosa MeSH
• membránové lipidy MeSH
• poly(propyleneimine) MeSH Prohlížeč
• polypropyleny MeSH

Saccharomyces cerevisiae pell and crd1 mutants deficient in the biosynthesis of mitochondrial phosphatidylglycerol (PG) and cardiolipin (CL) as well as Kluyveromyces lactis mutants impaired in the respiratory chain function (RCF) containing dysfunctional mitochondria show altered sensitivity to metabolic inhibitors. The S. cerevisiae pell mutant displayed increased sensitivity to cycloheximide, chloramphenicol, oligomycin and the cell-wall perturbing agents caffeine, caspofungin and hygromycin. On the other hand, the pel1 mutant was less sensitive to fluconazole, similarly as the K. lactis mutants impaired in the function of mitochondrial cytochromes. Mitochondrial dysfunction resulting either from the absence of PG and CL or impairment of the RCF presumably renders the cells more resistant to fluconazole. The increased tolerance of K. lactis respiratory chain mutants to amphotericin B, caffeine and hygromycin is probably related to a modification of the cell wall.

• MeSH
• antifungální látky farmakologie   MeSH
• buněčná stěna fyziologie   MeSH
• fosfatidylglyceroly genetika   metabolismus   MeSH
• fungální léková rezistence genetika   MeSH
• kardiolipiny genetika   metabolismus   MeSH
• Kluyveromyces účinky léků   genetika   MeSH
• mikrobiální testy citlivosti MeSH
• mitochondriální DNA genetika   MeSH
• mitochondrie genetika   fyziologie   MeSH
• mutace MeSH
• Saccharomyces cerevisiae účinky léků   genetika   MeSH
• transport elektronů * účinky léků   genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antifungální látky MeSH
• fosfatidylglyceroly MeSH
• kardiolipiny MeSH
• mitochondriální DNA MeSH