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 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.

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 Major Facilitator Superfamily Transporter Gene FgMFS1 Is Essential for Fusarium graminearum to Deal with Salicylic Acid Stress and for Its Pathogenicity towards Wheat

2021 ◽  
Vol 22 (16) ◽  
pp. 8497
Author(s):  
Qing Chen ◽  
Lu Lei ◽  
Caihong Liu ◽  
Yazhou Zhang ◽  
Qiang Xu ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Fusarium Graminearum ◽  
Total Yield ◽  
Acid Stress ◽  
Major Facilitator Superfamily ◽  
Dimensional Structure ◽  
Transporter Gene ◽  
Loss Of Function ◽  
Head Blight ◽  
Major Facilitator

Wheat is a major staple food crop worldwide, due to its total yield and unique processing quality. Its grain yield and quality are threatened by Fusarium head blight (FHB), which is mainly caused by Fusarium graminearum. Salicylic acid (SA) has a strong and toxic effect on F. graminearum and is a hopeful target for sustainable control of FHB. F. graminearum is capable of efficientdealing with SA stress. However, the underlying mechanisms remain unclear. Here, we characterized FgMFS1 (FGSG_03725), a major facilitator superfamily (MFS) transporter gene in F. graminearum. FgMFS1 was highly expressed during infection and was upregulated by SA. The predicted three-dimensional structure of the FgMFS1 protein was consistent with the schematic for the antiporter. The subcellular localization experiment indicated that FgMFS1 was usually expressed in the vacuole of hyphae, but was alternatively distributed in the cell membrane under SA treatment, indicating an element of F. graminearum in response to SA. ΔFgMFS1 (loss of function mutant of FgMFS1) showed enhanced sensitivity to SA, less pathogenicity towards wheat, and reduced DON production under SA stress. Re-introduction of a functional FgMFS1 gene into ∆FgMFS1 recovered the mutant phenotypes. Wheat spikes inoculated with ΔFgMFS1 accumulated more SA when compared to those inoculated with the wild-type strain. Ecotopic expression of FgMFS1 in yeast enhanced its tolerance to SA as expected, further demonstrating that FgMFS1 functions as an SA exporter. In conclusion, FgMFS1 encodes an SA exporter in F. graminearum, which is critical for its response to wheat endogenous SA and pathogenicity towards wheat.

scholarly journals Enhanced Efflux Pump Expression in Candida Mutants Results in Decreased Manogepix Susceptibility

2020 ◽  
Vol 64 (5) ◽  
Author(s):  
Sean D. Liston ◽  
Luke Whitesell ◽  
Mili Kapoor ◽  
Karen Joy Shaw ◽  
Leah E. Cowen
Keyword(s):  
Fungal Pathogens ◽  
Candida Parapsilosis ◽  
Efflux Pump ◽  
Major Facilitator Superfamily ◽  
Transporter Gene ◽  
Transcription Factor Gene ◽  
Content Type ◽  
Atp Binding Cassette Transporter ◽  
Major Facilitator Superfamily Transporter ◽  
Major Facilitator

ABSTRACT Manogepix is a broad-spectrum antifungal agent that inhibits glycosylphosphatidylinositol (GPI) anchor biosynthesis. Using whole-genome sequencing, we characterized two efflux-mediated mechanisms in the fungal pathogens Candida albicans and Candida parapsilosis that resulted in decreased manogepix susceptibility. In C. albicans, a gain-of-function mutation in the transcription factor gene ZCF29 activated expression of ATP-binding cassette transporter genes CDR11 and SNQ2. In C. parapsilosis, a mitochondrial deletion activated expression of the major facilitator superfamily transporter gene MDR1.

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 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.

scholarly journals Evidence of Evolutionary Conservation of Function between the Thyroxine Transporter Oatp1c1 and Major Facilitator Superfamily Members

Endocrinology ◽  
2010 ◽  
Vol 151 (12) ◽  
pp. 5941-5951 ◽  
Author(s):  
Daniel E. Westholm ◽  
Jacob D. Marold ◽  
Kevin J. Viken ◽  
Alicia H. Duerst ◽  
Grant W. Anderson ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Amino Acid ◽  
Substrate Binding ◽  
Evolutionary Conservation ◽  
Major Facilitator Superfamily ◽  
Transport Activity ◽  
Wild Type ◽  
Michaelis Constant ◽  
High Affinity ◽  
Major Facilitator

Organic anion transporting polypeptide 1c1 (Oatp1c1) is a high-affinity T4 transporter expressed in brain barrier cells. To identify Oatp1c1 amino acid residues critical for T4 transport, consensus membrane topology was predicted and a three-dimensional Oatp1c1 structure was generated using the known structures of major facilitator superfamily (MFS) transporters, glycerol 3-phosphate transporter, lactose permease, and the multidrug transporter Escherichia coli multidrug resistance protein D as templates. A total of nine amino acid mutations were generated based on amino acid conservation, localization to putative transmembrane domains, and side chain functionality. Mutant constructs were transiently transfected into human embryonic kidney 293 cells and assessed for plasma membrane localization and the capacity to transport substrate 125I-T4. Wild-type Oatp1c1, R601S, P609A, W277A/W278A, W277F/W278F, G399A/G409A, and G399L/G409L were all expressed at the plasma membrane. Wild-type Oatp1c1 and W277F/W278F displayed biphasic T4 transport kinetics, albeit the mutant did so with an approximately 10-fold increase in high-affinity Michaelis constant. The W277A/W278A mutation abolished Oatp1c1 T4 transport. G399A/G409A and G399V/G409V mutants displayed near wild-type activity in an uptake screen but exhibited diminished T4 transport activity at high-substrate concentrations, suggesting a substrate binding site collapse or inability to convert between input and output states. Finally, transmembrane domain 11 mutants R601S and P609A displayed partial T4 transport activity with significantly reduced maximum velocities and higher Michaelis constant. Arg601 is functionally strongly conserved with members of the MFS whose structures and function have been extensively studied. These data provide the experimental foundation for mapping Oatp1c1 substrate binding sites and reveal evolutionary conservation with bacterial MFS transporter members.

Sign in / Sign up

Export Citation Format

Share Document