scholarly journals Diverse Functions of Plant Zinc-Induced Facilitator-like Transporter for Their Emerging Roles in Crop Trait Enhancement

Plants ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 102
Author(s):  
Varsha Meena ◽  
Shivani Sharma ◽  
Gazaldeep Kaur ◽  
Bhupinder Singh ◽  
Ajay Kumar Pandey
Keyword(s):  
Plasma Membrane ◽  
Micronutrient Deficiency ◽  
Major Facilitator Superfamily ◽  
Diverse Group ◽  
Crop Species ◽  
Auxin Homeostasis ◽  
Iron And Zinc ◽  
Major Facilitator ◽  
Dependent Processes ◽  
Insight Into

The major facilitator superfamily (MFS) is a large and diverse group of secondary transporters found across all kingdoms of life. Zinc-induced facilitator-like (ZIFL) transporters are the MFS family members that function as exporters driven by the antiporter-dependent processes. The presence of multiple ZIFL transporters was shown in various plant species, as well as in bryophytes. However, only a few ZIFLs have been functionally characterized in plants, and their localization has been suggested to be either on tonoplast or at the plasma membrane. A subset of the plant ZIFLs were eventually characterized as transporters due to their specialized role in phytosiderophores efflux and auxin homeostasis, and they were also proven to impart tolerance to micronutrient deficiency. The emerging functions of ZIFL proteins highlight their role in addressing important traits in crop species. This review aims to provide insight into and discuss the importance of plant ZIFL in various tissue-specific functions. Furthermore, a spotlight is placed on their role in mobilizing essential micronutrients, including iron and zinc, from the rhizosphere to support plant survival. In conclusion, in this paper, we discuss the functional redundancy of ZIFL transporters to understand their roles in developing specific traits in crop.

scholarly journals Pyridoxal-5′-phosphate–dependent bifunctional enzyme catalyzed biosynthesis of indolizidine alkaloids in fungi

2019 ◽  
Vol 117 (2) ◽  
pp. 1174-1180 ◽  
Author(s):  
Guang Zhi Dai ◽  
Wen Bo Han ◽  
Ya Ning Mei ◽  
Kuang Xu ◽  
Rui Hua Jiao ◽  
...  
Keyword(s):  
Polyketide Synthase ◽  
Complex Structure ◽  
Genome Mining ◽  
Biosynthetic Gene Cluster ◽  
Major Facilitator Superfamily ◽  
Molecular Architecture ◽  
Widespread Occurrence ◽  
Indolizidine Alkaloids ◽  
Major Facilitator ◽  
Insight Into

Indolizidine alkaloids such as anticancer drugs vinblastine and vincristine are exceptionally attractive due to their widespread occurrence, prominent bioactivity, complex structure, and sophisticated involvement in the chemical defense for the producing organisms. However, the versatility of the indolizidine alkaloid biosynthesis remains incompletely addressed since the knowledge about such biosynthetic machineries is only limited to several representatives. Herein, we describe the biosynthetic gene cluster (BGC) for the biosynthesis of curvulamine, a skeletally unprecedented antibacterial indolizidine alkaloid from Curvularia sp. IFB-Z10. The molecular architecture of curvulamine results from the functional collaboration of a highly reducing polyketide synthase (CuaA), a pyridoxal-5′-phosphate (PLP)-dependent aminotransferase (CuaB), an NADPH-dependent dehydrogenase (CuaC), and a FAD-dependent monooxygenase (CuaD), with its transportation and abundance regulated by a major facilitator superfamily permease (CuaE) and a Zn(II)Cys6 transcription factor (CuaF), respectively. In contrast to expectations, CuaB is bifunctional and capable of catalyzing the Claisen condensation to form a new C–C bond and the α-hydroxylation of the alanine moiety in exposure to dioxygen. Inspired and guided by the distinct function of CuaB, our genome mining effort discovers bipolamines A−I (bipolamine G is more antibacterial than curvulamine), which represent a collection of previously undescribed polyketide alkaloids from a silent BGC in Bipolaris maydis ATCC48331. The work provides insight into nature’s arsenal for the indolizidine-coined skeletal formation and adds evidence in support of the functional versatility of PLP-dependent enzymes in fungi.

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 Cysteine Mutants of the Major Facilitator Superfamily-Type Transporter CcoA Provide insight into Copper Import

2021 ◽  
Author(s):  
Khalfaoui-Hassani Bahia ◽  
Trasnea Petru-Iulian ◽  
Steimle Stefan ◽  
Koch Hans-Georg ◽  
Fevzi Daldal
Keyword(s):  
Conformational Changes ◽  
Structural Models ◽  
Major Facilitator Superfamily ◽  
Transmembrane Helices ◽  
Surface Loop ◽  
Major Facilitator ◽  
Copper Import ◽  
Cu Uptake ◽  
Insight Into

CcoA belongs to the widely distributed bacterial copper (Cu) importer subfamily CalT (CcoA-like Transporters) of the Major Facilitator Superfamily (MFS), and provides cytoplasmic Cu needed for cbb3-type cytochrome c oxidase (cbb3-Cox) biogenesis. Earlier studies have supported a 12 transmembrane helices (TMH) topology of CcoA with the well-conserved Met233xxxMet237 and His261xxxMet265 motifs in its TMH7 and TMH8, respectively. Of these residues, Met233 and His261 are essential for Cu uptake and cbb3-Cox production, whereas Met237 and Met265 contribute partly to these processes. CcoA also contains five Cys residues of unknown role, and remarkably, its structural models predict that three of these are exposed to the highly oxidizing periplasm. Here, we first demonstrate that elimination of both Met237 and Met265 completely abolishes Cu uptake and cbb3-Cox production, indicating that CcoA requires at least one of these two Met residues for activity. Second, using scanning mutagenesis to probe plausible metal-interacting Met, His and Cys residues of CcoA we found that the periplasm-exposed Cys49 located at the end of TMH2, the Cys247 on a surface loop between TMH7 and THM8, and the C367 located at the end of TMH11 are important for CcoA function. Analyses of the single and double Cys mutants revealed the occurrence of a disulfide bond in CcoA in vivo, possibly related to conformational changes it undergoes during Cu import as MFS-type transporter. Our overall findings suggested a model linking Cu import for cbb3-Cox biogenesis with a thiol: disulfide oxidoreduction step, advancing our understanding of the mechanisms of CcoA function.

scholarly journals It takes two to tango: The dance of the permease

2019 ◽  
Vol 151 (7) ◽  
pp. 878-886 ◽  
Author(s):  
H. Ronald Kaback ◽  
Lan Guan
Keyword(s):  
Binding Sites ◽  
Cytoplasmic Membrane ◽  
Major Facilitator Superfamily ◽  
Internal Cavity ◽  
Lactose Permease ◽  
Physiological Conditions ◽  
Membrane Transport Proteins ◽  
Major Facilitator ◽  
Alternating Access ◽  
Insight Into

The lactose permease (LacY) of Escherichia coli is the prototype of the major facilitator superfamily, one of the largest families of membrane transport proteins. Structurally, two pseudo-symmetrical six-helix bundles surround a large internal aqueous cavity. Single binding sites for galactoside and H+ are positioned at the approximate center of LacY halfway through the membrane at the apex of the internal cavity. These features enable LacY to function by an alternating-access mechanism that can catalyze galactoside/H+ symport in either direction across the cytoplasmic membrane. The H+-binding site is fully protonated under physiological conditions, and subsequent sugar binding causes transition of the ternary complex to an occluded intermediate that can open to either side of the membrane. We review the structural and functional evidence that has provided new insight into the mechanism by which LacY achieves active transport against a concentration gradient.

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.

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.

The human iron exporter ferroportin. Insight into the transport mechanism by molecular modeling

2016 ◽  
Vol 12 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Valentina Tortosa ◽  
Maria Carmela Bonaccorsi di Patti ◽  
Giovanni Musci ◽  
Fabio Polticelli
Keyword(s):  
Molecular Modeling ◽  
Transport Mechanism ◽  
Structural Models ◽  
Degradation Pathway ◽  
Atomic Level ◽  
Major Facilitator Superfamily ◽  
Wild Type ◽  
Major Facilitator ◽  
First Time ◽  
Insight Into

AbstractFerroportin, a membrane protein belonging to the major facilitator superfamily of transporters, is the only vertebrate iron exporter known so far. Several ferroportin mutations lead to the so-called ferroportin disease or type 4 hemochromatosis, characterized by two distinct iron accumulation phenotypes depending on whether the mutation affects the activity of the protein or its degradation pathway. Through extensive molecular modeling analyses using the structure of all known major facilitator superfamily members as templates, multiple structural models of ferroportin in the three mechanistically relevant conformations (inward open, occluded, and outward open) have been obtained. The best models, selected on the ground of experimental data available on wild-type and mutant ferroportion, provide for the first time a prediction at the atomic level of the dynamics of the transporter. Based on these results, a possible mechanism for iron export is proposed.

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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