scholarly journals Identification of anN-Acetylglucosamine Transporter That Mediates Hyphal Induction inCandida albicans

2007 ◽  
Vol 18 (3) ◽  
pp. 965-975 ◽  
Author(s):  
Francisco J. Alvarez ◽  
James B. Konopka
Keyword(s):  
Plasma Membrane ◽  
Hyphal Growth ◽  
Nutrient Sensing ◽  
Major Facilitator Superfamily ◽  
Cellular Processes ◽  
Macrophage Phagocytosis ◽  
Wide Range ◽  
High Concentrations ◽  
Hyphal Formation ◽  
Major Facilitator

The sugar N-acetylglucosamine (GlcNAc) plays an important role in nutrient sensing and cellular regulation in a wide range of organisms from bacteria to humans. In the fungal pathogen Candida albicans, GlcNAc induces a morphological transition from budding to hyphal growth. Proteomic comparison of plasma membrane proteins from buds and from hyphae induced by GlcNAc identified a novel hyphal protein (Ngt1) with similarity to the major facilitator superfamily of transporters. An Ngt1-GFP fusion was detected in the plasma membrane after induction with GlcNAc, but not other related sugars. Ngt1-GFP was also induced by macrophage phagocytosis, suggesting a role for the GlcNAc response in signaling entry into phagolysosomes. NGT1 is needed for efficient GlcNAc uptake and for the ability to induce hyphae at low GlcNAc concentrations. High concentrations of GlcNAc could bypass the need for NGT1 to induce hyphae, indicating that elevated intracellular levels of GlcNAc induce hyphal formation. Expression of NGT1 in Saccharomyces cerevisiae promoted GlcNAc uptake, indicating that Ngt1 acts directly as a GlcNAc transporter. Transport mediated by Ngt1 was specific, as other sugars could not compete for the uptake of GlcNAc. Thus, Ngt1 represents the first eukaryotic GlcNAc transporter to be discovered. The presence of NGT1 homologues in the genome sequences of a wide range of eukaryotes from yeast to mammals suggests that they may also function in the cellular processes regulated by GlcNAc, including those that underlie important diseases such as cancer and diabetes.

scholarly journals The Varied Role of Efflux Pumps of the MFS Family in the Interplay of Bacteria with Animal and Plant Cells

2019 ◽  
Vol 7 (9) ◽  
pp. 285 ◽  
Author(s):  
Pasqua ◽  
Grossi ◽  
Zennaro ◽  
Fanelli ◽  
Micheli ◽  
...  
Keyword(s):  
Regulatory Networks ◽  
Efflux Pump ◽  
Efflux Pumps ◽  
Major Facilitator Superfamily ◽  
Host Cells ◽  
Multidrug Efflux ◽  
Animal Cells ◽  
Multidrug Efflux Pumps ◽  
Wide Range ◽  
Major Facilitator

Efflux pumps represent an important and large group of transporter proteins found in all organisms. The importance of efflux pumps resides in their ability to extrude a wide range of antibiotics, resulting in the emergence of multidrug resistance in many bacteria. Besides antibiotics, multidrug efflux pumps can also extrude a large variety of compounds: Bacterial metabolites, plant-produced compounds, quorum-sensing molecules, and virulence factors. This versatility makes efflux pumps relevant players in interactions not only with other bacteria, but also with plant or animal cells. The multidrug efflux pumps belonging to the major facilitator superfamily (MFS) are widely distributed in microbial genomes and exhibit a large spectrum of substrate specificities. Multidrug MFS efflux pumps are present either as single-component transporters or as tripartite complexes. In this review, we will summarize how the multidrug MFS efflux pumps contribute to the interplay between bacteria and targeted host cells, with emphasis on their role in bacterial virulence, in the colonization of plant and animal host cells and in biofilm formation. We will also address the complexity of these interactions in the light of the underlying regulatory networks required for the effective activation of efflux pump genes.

scholarly journals Resistance and Adaptation to Quinidine in Saccharomyces cerevisiae: Role of QDR1 (YIL120w), Encoding a Plasma Membrane Transporter of the Major Facilitator Superfamily Required for Multidrug Resistance

2001 ◽  
Vol 45 (5) ◽  
pp. 1528-1534 ◽  
Author(s):  
Patrı́cia A. Nunes ◽  
Sandra Tenreiro ◽  
Isabel Sá-Correia
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Plasma Membrane ◽  
Multidrug Resistance ◽  
Fluorescent Protein ◽  
Resistance Mechanisms ◽  
Major Facilitator Superfamily ◽  
Yeast Cells ◽  
Detectable Effect ◽  
Protein Fusion ◽  
Major Facilitator

ABSTRACT As predicted based on structural considerations, we show results indicating that the member of the major facilitator superfamily encoded by Saccharomyces cerevisiae open reading frameYIL120w is a multidrug resistance determinant. Yil120wp was implicated in yeast resistance to ketoconazole and quinidine, but not to the stereoisomer quinine; the gene was thus named QDR1. Qdr1p was proved to alleviate the deleterious effects of quinidine, revealed by the loss of cell viability following sudden exposure of the unadapted yeast population to the drug, and to allow the earlier eventual resumption of exponential growth under quinidine stress. However, QDR1 gene expression had no detectable effect on the susceptibility of yeast cells previously adapted to quinidine. Fluorescence microscopy observation of the distribution of the Qdr1-green fluorescent protein fusion protein in living yeast cells indicated that Qdr1p is a plasma membrane protein. We also show experimental evidence indicating that yeast adaptation to growth with quinidine involves the induction of active expulsion of the drug from preloaded cells, despite the fact that this antiarrhythmic and antimalarial quinoline ring-containing drug is not present in the yeast natural environment. However, we were not able to prove that Qdr1p is directly implicated in this export. Results clearly suggest that there are other unidentified quinidine resistance mechanisms that can be used in the absence of QDR1.

The putative permease PhlE of Pseudomonas fluorescens F113 has a role in 2,4-diacetylphloroglucinol resistance and in general stress tolerance

Microbiology ◽  
2004 ◽  
Vol 150 (7) ◽  
pp. 2443-2450 ◽  
Author(s):  
Abdelhamid Abbas ◽  
John E. McGuire ◽  
Delores Crowley ◽  
Christine Baysse ◽  
Max Dow ◽  
...  
Keyword(s):  
Pseudomonas Fluorescens ◽  
Stress Tolerance ◽  
Major Facilitator Superfamily ◽  
Control Activity ◽  
Transmembrane Segments ◽  
General Stress ◽  
Intermediate Metabolites ◽  
Primary Determinant ◽  
High Concentrations ◽  
Major Facilitator

2,4-Diacetylphloroglucinol (PHL) is the primary determinant of the biological control activity of Pseudomonas fluorescens F113. The operon phlACBD encodes enzymes responsible for PHL biosynthesis from intermediate metabolites. The phlE gene, which is located downstream of the phlACBD operon, encodes a putative permease suggested to be a member of the major facilitator superfamily with 12 transmembrane segments. PhlE has been suggested to function in PHL export. Here the sequencing of the phlE gene from P. fluorescens F113 and the construction of a phlE null mutant, F113-D3, is reported. It is shown that F113-D3 produced less PHL than F113. The ratio of cell-associated to free PHL was not significantly different between the strains, suggesting the existence of alternative transporters for PHL. The phlE mutant was, however, significantly more sensitive to high concentrations of added PHL, implicating PhlE in PHL resistance. Furthermore, the phlE mutant was more susceptible to osmotic, oxidative and heat-shock stresses. Osmotic stress induced rapid degradation of free PHL by the bacteria. Based on these results, we propose that the role of phlE in general stress tolerance is to export toxic intermediates of PHL degradation from the cells.

scholarly journals Sialic acid acquisition in bacteria–one substrate, many transporters

2016 ◽  
Vol 44 (3) ◽  
pp. 760-765 ◽  
Author(s):  
Gavin H. Thomas
Keyword(s):  
Sialic Acid ◽  
Immune Evasion ◽  
Sialic Acids ◽  
Major Facilitator Superfamily ◽  
Acid Uptake ◽  
Gram Negative Bacteria ◽  
Acetylneuraminic Acid ◽  
Wide Range ◽  
Major Facilitator

The sialic acids are a family of 9-carbon sugar acids found predominantly on the cell-surface glycans of humans and other animals within the Deuterostomes and are also used in the biology of a wide range of bacteria that often live in association with these animals. For many bacteria sialic acids are simply a convenient source of food, whereas for some pathogens they are also used in immune evasion strategies. Many bacteria that use sialic acids derive them from the environment and so are dependent on sialic acid uptake. In this mini-review I will describe the discovery and characterization of bacterial sialic acids transporters, revealing that they have evolved multiple times across multiple diverse families of transporters, including the ATP-binding cassette (ABC), tripartite ATP-independent periplasmic (TRAP), major facilitator superfamily (MFS) and sodium solute symporter (SSS) transporter families. In addition there is evidence for protein-mediated transport of sialic acids across the outer membrane of Gram negative bacteria, which can be coupled to periplasmic processing of different sialic acids to the most common form, β-D-N-acetylneuraminic acid (Neu5Ac) that is most frequently taken up into the cell.

scholarly journals Disrupted in renal carcinoma 2 (DIRC2), a novel transporter of the lysosomal membrane, is proteolytically processed by cathepsin L

2011 ◽  
Vol 439 (1) ◽  
pp. 113-128 ◽  
Author(s):  
Lalu Rudyat Telly Savalas ◽  
Bruno Gasnier ◽  
Markus Damme ◽  
Torben Lübke ◽  
Christian Wrocklage ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Renal Carcinoma ◽  
Cathepsin L ◽  
Chromosomal Translocation ◽  
Outward Current ◽  
Surface Expression ◽  
Proteolytic Processing ◽  
Major Facilitator Superfamily ◽  
Amino Acid Residues ◽  
Major Facilitator

DIRC2 (Disrupted in renal carcinoma 2) has been initially identified as a breakpoint-spanning gene in a chromosomal translocation putatively associated with the development of renal cancer. The DIRC2 protein belongs to the MFS (major facilitator superfamily) and has been previously detected by organellar proteomics as a tentative constituent of lysosomal membranes. In the present study, lysosomal residence of overexpressed as well as endogenous DIRC2 was shown by several approaches. DIRC2 is proteolytically processed into a N-glycosylated N-terminal and a non-glycosylated C-terminal fragment respectively. Proteolytic cleavage occurs in lysosomal compartments and critically depends on the activity of cathepsin L which was found to be indispensable for this process in murine embryonic fibroblasts. The cleavage site within DIRC2 was mapped between amino acid residues 214 and 261 using internal epitope tags, and is presumably located within the tentative fifth intralysosomal loop, assuming the typical MFS topology. Lysosomal targeting of DIRC2 was demonstrated to be mediated by a N-terminal dileucine motif. By disrupting this motif, DIRC2 can be redirected to the plasma membrane. Finally, in a whole-cell electrophysiological assay based on heterologous expression of the targeting mutant at the plasma membrane of Xenopus oocytes, the application of a complex metabolic mixture evokes an outward current associated with the surface expression of full-length DIRC2. Taken together, these data strongly support the idea that DIRC2 is an electrogenic lysosomal metabolite transporter which is subjected to and presumably modulated by limited proteolytic processing.

scholarly journals PdMFS1 Transporter Contributes to Penicilliun digitatum Fungicide Resistance and Fungal Virulence during Citrus Fruit Infection

2019 ◽  
Vol 5 (4) ◽  
pp. 100 ◽  
Author(s):  
Marta de Ramón-Carbonell ◽  
Mario López-Pérez ◽  
Luis González-Candelas ◽  
Paloma Sánchez-Torres
Keyword(s):  
Fungicide Resistance ◽  
Citrus Fruit ◽  
Major Facilitator Superfamily ◽  
Fungal Virulence ◽  
Disease Symptoms ◽  
Knock Out ◽  
Wide Range ◽  
Major Facilitator ◽  
Chemical Fungicides ◽  
Mfs Transporter

A new Penicillium digitatum major facilitator superfamily (MFS) transporter (PdMFS1) was identified and functionally characterized in order to shed more light on the mechanisms underlying fungicide resistance. PdMFS1 can play an important role in the intensification of resistance to fungicides normally used in P. digitatum postharvest treatments. In the PdMFS1 disrupted mutants, a slight effect in response to chemical fungicides was observed, but fungicide sensitivity was highly affected in the overexpression mutants which became resistant to wide range of chemical fungicides. Moreover, P. digitatum knock-out mutants exhibited a lower rate of fungal virulence when infected oranges were stored at 20 °C. Disease symptoms were higher in the PdMFS1 overexpression mutants coming from the low-virulent P. digitatum parental strain. In addition, the gene expression analysis showed an induction of PdMFS1 transcription in all overexpression mutants regardless from which progenitor came from, and four-time intensification of the parental wild type strain during citrus infection reinforcing PdMFS1 role in fungal virulence. The P. digitatum MFS transporter PdMFS1 contributes not only to the acquisition of wide range of fungicide resistance but also in fungal virulence during citrus infection.

Molecular characterization and expression pattern of sorbitol transporter gene PbSOT2 in Pear (Pyrus bretschneideri Rehd.) fruit

2016 ◽  
Vol 96 (1) ◽  
pp. 128-137 ◽  
Author(s):  
Lifen Wang ◽  
Xiaoxiao Qi ◽  
Yanan Yang ◽  
Shaoling Zhang
Keyword(s):  
Plasma Membrane ◽  
Phloem Loading ◽  
Major Facilitator Superfamily ◽  
Transporter Gene ◽  
Full Bloom ◽  
Calculated Molecular Mass ◽  
Total Sugars ◽  
Rapid Enlargement ◽  
Photosynthetic Product ◽  
Major Facilitator

Sorbitol is a primary photosynthetic product and the principal photosynthetic transport substance in plants of the Rosaceae. Sorbitol transporters in the major facilitator superfamily (MFS) are important for phloem loading and sorbitol uptake into sink tissues. Here we report the cloning, localization, and expression analysis of a sorbitol transporter in fruit of Pyrus bretschneideri Rehd. cv. “Yali.” This clone, named PbSOT2, encoded a 537-aa protein with a calculated molecular mass of 57.92 kDa. The predicted protein had 12 transmembrane domains and belonged to the MFS carriers. PbSOT2 was sub-cellularly targeted to the plasma membrane. The expression of PbSOT2 was highest during the rapid enlargement phase of fruit (100 days after full bloom). In addition, the sorbitol content in fruit fluctuated within certain limits, but its proportion of total sugars decreased continuously. This work shows that PbSOT2 may play a role in fruit enlargement and the accumulation of hexose during fruit development.

scholarly journals The Arabidopsis SAC9 Enzyme defines a cortical population of early endosomes and restricts PI(4,5)P2 to the Plasma Membrane

2021 ◽  
Author(s):  
Mehdi Doumane ◽  
Alexis Lebecq ◽  
Aurelie Fangain ◽  
Vincent Bayle ◽  
Frederique Rozier ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cell Cortex ◽  
Cellular Processes ◽  
Phosphoinositide Phosphatase ◽  
Early Endosomes ◽  
Wide Range ◽  
Intracellular Compartments ◽  
Functional Consequences ◽  
Src Homology ◽  
Golgi Network

Membranes lipids, and especially phosphoinositides, are differentially enriched within the eukaryotic endomembrane system. This generates a landmark code by modulating the properties of each membrane. Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] specifically accumulates at the plasma membrane in yeast, animal and plant cells, where it regulates a wide range of cellular processes including endocytosis. However, the functional consequences of mispatterning PI(4,5)P2 in plants are unknown. Here, we functionally characterized the phosphoinositide phosphatase SUPPRESSOR OF ACTIN9 (SAC9) in Arabidopsis thaliana (Arabidopsis). We found that SAC9 depletion led to the ectopic localization of PI(4,5)P2 on cortical intracellular compartments, which depends on PI4P and PI(4,5)P2 production at the plasma membrane. SAC9 localizes to a subpopulation of trans-Golgi Network/early endosomes that are spatially restricted to a region close to the cell cortex and that are coated with clathrin. Furthermore, it interacts and colocalizes with the endocytic component Src Homology 3 Domain Protein 2 (SH3P2). In the absence of SAC9, SH3P2 localization is altered and the clathrin mediated endocytosis rate is significantly reduced. Thus, SAC9 is required to maintain efficient endocytic uptake, highlighting the importance of restricting the PI(4,5)P2 pool at the plasma membrane for the proper regulation of endocytosis in plants.

scholarly journals Alpha-arrestins Aly1 and Aly2 regulate trafficking of the glycerophosphoinositol transporter Git1 and impact phospholipid homeostasis

2021 ◽  
Author(s):  
Benjamin P. Robinson ◽  
Sarah Hawbaker ◽  
Annette Chiang ◽  
Eric M. Jordahl ◽  
Sanket Anaokar ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Protein Trafficking ◽  
Inositol Phosphate ◽  
Nutrient Balance ◽  
Building Blocks ◽  
Water Soluble ◽  
Major Facilitator Superfamily ◽  
Protein Levels ◽  
Major Facilitator

AbstractPhosphatidylinositol (PI) is an essential phospholipid and critical component of membrane bilayers. The complete deacylation of PI by phospholipases of the B-type leads to the production of intracellular and extracellular glycerophosphoinositol (GPI), a water-soluble glycerophosphodiester. Extracellular GPI is transported into the cell via Git1, a member of the Major Facilitator Superfamily of transporters that resides at the plasma membrane in yeast. Once internalized, GPI can be degraded to produce inositol, phosphate and glycerol, thereby contributing to reserves of these building blocks. Not surprisingly, GIT1 gene expression is controlled by nutrient balance, with limitation for phosphate or inositol each increasing GIT1 expression to facilitate GPI uptake. Less is known about how Git1 protein levels or localization are controlled. Here we show that the α-arrestins, an important class of protein trafficking adaptor, regulate the localization of Git1 in a manner dependent upon their association with the ubiquitin ligase Rsp5. Specifically, α-arrestin Aly2 is needed for effective Git1 internalization from the plasma membrane under basal conditions. However, in response to GPI-treatment of cells, either Aly1 or Aly2 can promote Git1 trafficking to the vacuole. Retention of Git1 at the cell surface, as occurs in aly1Δ aly2Δ cells, results in impaired growth in the presences of excess exogenous GPI and results in increased uptake of radiolabeled GPI, suggesting that accumulation of this metabolite or its downstream products leads to cellular toxicity. We further show that regulation of α-arrestin Aly1 by the protein phosphatase calcineurin improves both steady-state and ligand-induced trafficking of Git1 when a mutant allele of Aly1 that mimics the dephosphorylated state at calcineurin-regulated residues is employed. Thus, calcineurin regulation of Aly1 is important for the GPI-ligand induced trafficking of Git1 by this α-arrestin, however, the role of calcineurin in regulating Git1 trafficking is much broader than can simply be explained by regulation of the α-arrestins. Finally, we find that loss of Aly1 and Aly2 leads to an increase in phosphatidylinositol-3-phosphate on the limiting membrane of the vacuole and this alteration is further exacerbated by addition of GPI, suggesting that the effect is at least partially linked to Git1 function. Indeed, loss of Aly1 and Aly2 leads to increased incorporation of inositol label from 3H-inositol-labelled GPI into PI, confirming that internalized GPI influences PI synthesis and indicating a role for the α-arrestins in regulating the process.

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