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Kim JH, Mailloux L, Bloor D, Tae H, Nguyen H, McDowell M, Padilla J, DeWaard A. Multiple roles for the cytoplasmic C-terminal domains of the yeast cell surface receptors Rgt2 and Snf3 in glucose sensing and signaling. Sci Rep 2024; 14:4055. [PMID: 38374219 PMCID: PMC10876965 DOI: 10.1038/s41598-024-54628-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 02/14/2024] [Indexed: 02/21/2024] Open
Abstract
The plasma membrane proteins Rgt2 and Snf3 are glucose sensing receptors (GSRs) that generate an intracellular signal for the induction of gene expression in response to high and low extracellular glucose concentrations, respectively. The GSRs consist of a 12-transmembrane glucose recognition domain and a cytoplasmic C-terminal signaling tail. The GSR tails are dissimilar in length and sequence, but their distinct roles in glucose signal transduction are poorly understood. Here, we show that swapping the tails between Rgt2 and Snf3 does not alter the signaling activity of the GSRs, so long as their tails are phosphorylated in a Yck-dependent manner. Attachment of the GSR tails to Hxt1 converts the transporter into a glucose receptor; however, the tails attached to Hxt1 are not phosphorylated by the Ycks, resulting in only partial signaling. Moreover, in response to non-fermentable carbon substrates, Rgt2 and Hxt1-RT (RT, Rgt2-tail) are efficiently endocytosed, whereas Snf3 and Hxt1-ST (ST, Snf3-tail) are endocytosis-impaired. Thus, the tails are important regulatory domains required for the endocytosis of the Rgt2 and Snf3 glucose sensing receptors triggered by different cellular stimuli. Taken together, these results suggest multiple roles for the tail domains in GSR-mediated glucose sensing and signaling.
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Affiliation(s)
- Jeong-Ho Kim
- Department of Biology and Chemistry, Liberty University, 1971 University Blvd, Lynchburg, VA, 24502, USA.
| | - Levi Mailloux
- Department of Biology and Chemistry, Liberty University, 1971 University Blvd, Lynchburg, VA, 24502, USA
| | - Daniel Bloor
- Department of Biology and Chemistry, Liberty University, 1971 University Blvd, Lynchburg, VA, 24502, USA
| | - Haeun Tae
- Department of Biology and Chemistry, Liberty University, 1971 University Blvd, Lynchburg, VA, 24502, USA
| | - Han Nguyen
- Department of Biology and Chemistry, Liberty University, 1971 University Blvd, Lynchburg, VA, 24502, USA
| | - Morgan McDowell
- Department of Biology and Chemistry, Liberty University, 1971 University Blvd, Lynchburg, VA, 24502, USA
| | - Jaqueline Padilla
- Department of Biology and Chemistry, Liberty University, 1971 University Blvd, Lynchburg, VA, 24502, USA
| | - Anna DeWaard
- Department of Biology and Chemistry, Liberty University, 1971 University Blvd, Lynchburg, VA, 24502, USA
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Kim JH, Mailloux L, Bloor D, Maddox B, Humble J. The role of salt bridge networks in the stability of the yeast hexose transporter 1. Biochim Biophys Acta Gen Subj 2023; 1867:130490. [PMID: 37844739 DOI: 10.1016/j.bbagen.2023.130490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/06/2023] [Accepted: 10/12/2023] [Indexed: 10/18/2023]
Abstract
BACKGROUND The yeast S. cerevisiae preferably metabolizes glucose through aerobic glycolysis. Glucose transport is facilitated by multiple hexose transporters (Hxts), and their expression and activity are tightly regulated by multiple mechanisms. However, detailed structural and functional analyses of Hxts remain limited, largely due to the lack of crystal structure. METHODS Homology modeling was used to build a 3D structural model for the yeast glucose transporter Hxt1 and investigate the effects of site directed mutations on Hxt1 stability and glucose transport activity. RESULTS The conserved salt bridge-forming residues observed in the human Glut4 and the yeast glucose receptor Rgt2 were identified within and between the two 6-transmembrane spanning segments of Hxt1. Most of the RGT2 mutations that disrupt the salt bridge networks were known to cause constitutive signal generation, whereas the corresponding substitutions in HXT1 were shown to decrease Hxt1 stability. While substitutions of the two residues in the salt bridge 2 in Glut4-E329Q and E393D-were reported to abolish glucose transport, the equivalent substitutions in Hxt1 (D382Q and E454D) did not affect Hxt1 glucose transport activity. CONCLUSIONS Substitutions of equivalent salt bridge-forming residues in Hxt1, Rgt2, and Glut4 are predicted to lock them in an inward-facing conformation but lead to different functional consequences. GENERAL SIGNIFICANCE The salt bridge networks in yeast and human glucose transporters and yeast glucose receptors may play different roles in maintaining their structural and functional integrity.
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Affiliation(s)
- Jeong-Ho Kim
- Department of Biology and Chemistry, Liberty University, 1971 University Blvd, Lynchburg, VA 24502, USA.
| | - Levi Mailloux
- Department of Biology and Chemistry, Liberty University, 1971 University Blvd, Lynchburg, VA 24502, USA
| | - Daniel Bloor
- Department of Biology and Chemistry, Liberty University, 1971 University Blvd, Lynchburg, VA 24502, USA
| | - Bradley Maddox
- Department of Biology and Chemistry, Liberty University, 1971 University Blvd, Lynchburg, VA 24502, USA
| | - Julia Humble
- Department of Biology and Chemistry, Liberty University, 1971 University Blvd, Lynchburg, VA 24502, USA
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Simpson-Lavy K, Kupiec M. Glucose Inhibits Yeast AMPK (Snf1) by Three Independent Mechanisms. BIOLOGY 2023; 12:1007. [PMID: 37508436 PMCID: PMC10376661 DOI: 10.3390/biology12071007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 07/13/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023]
Abstract
Snf1, the fungal homologue of mammalian AMP-dependent kinase (AMPK), is a key protein kinase coordinating the response of cells to a shortage of glucose. In fungi, the response is to activate respiratory gene expression and metabolism. The major regulation of Snf1 activity has been extensively investigated: In the absence of glucose, it becomes activated by phosphorylation of its threonine at position 210. This modification can be erased by phosphatases when glucose is restored. In the past decade, two additional independent mechanisms of Snf1 regulation have been elucidated. In response to glucose (or, surprisingly, also to DNA damage), Snf1 is SUMOylated by Mms21 at lysine 549. This inactivates Snf1 and leads to Snf1 degradation. More recently, glucose-induced proton export has been found to result in Snf1 inhibition via a polyhistidine tract (13 consecutive histidine residues) at the N-terminus of the Snf1 protein. Interestingly, the polyhistidine tract plays also a central role in the response to iron scarcity. This review will present some of the glucose-sensing mechanisms of S. cerevisiae, how they interact, and how their interplay results in Snf1 inhibition by three different, and independent, mechanisms.
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Affiliation(s)
- Kobi Simpson-Lavy
- The Shmunis School of Biomedicine & Cancer Research, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
| | - Martin Kupiec
- The Shmunis School of Biomedicine & Cancer Research, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
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4
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Kim JH, Bloor D, Rodriguez R, Mohler E, Mailloux L, Melton S, Jung D. Casein kinases are required for the stability of the glucose-sensing receptor Rgt2 in yeast. Sci Rep 2022; 12:1598. [PMID: 35102180 PMCID: PMC8803954 DOI: 10.1038/s41598-022-05569-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 01/12/2022] [Indexed: 11/30/2022] Open
Abstract
In yeast, glucose induction of HXT (glucose transporter gene) expression is achieved via the Rgt2 and Snf3 glucose sensing receptor (GSR)-mediated signal transduction pathway. The membrane-associated casein kinases Yck1 and Yck2 (Ycks) are involved in this pathway, but their exact role remains unclear. Previous work suggests that the Ycks are activated by the glucose-bound GSRs and transmit the glucose signal from the plasma membrane to the nucleus. However, here we provide evidence that the YCks are constitutively active and required for the stability of the Rgt2 receptor. Cell surface levels of Rgt2 are significantly decreased in a yck1Δyck2ts mutant, but this is not due to endocytosis-mediated vacuolar degradation of the receptor. Similar observations are made in an akr1Δ mutant, where the Ycks are no longer associated with the membrane, and in a sod1Δ mutant in which the kinases are unstable. Of note, in an akr1Δ mutant, both the Ycks and Rgt2 are mislocalized to the cytoplasm, where Rgt2 is stable and functions as an effective receptor for glucose signaling. We also demonstrate that Rgt2 is phosphorylated on the putative Yck consensus phosphorylation sites in its C-terminal domain (CTD) in a Yck-dependent manner and that this glucose-induced modification is critical for its stability and function. Thus, these results indicate a role for the Ycks in stabilizing Rgt2 and suggest that Rgt2 may use glucose binding as a molecular switch not to activate the Ycks but to promote Yck-dependent interaction and phosphorylation of the CTD that increases its stability.
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Affiliation(s)
- Jeong-Ho Kim
- Department of Biology and Chemistry, Liberty University, 1971 University Blvd, Lynchburg, VA, 24502, USA.
| | - Daniel Bloor
- Department of Biology and Chemistry, Liberty University, 1971 University Blvd, Lynchburg, VA, 24502, USA
| | - Rebeca Rodriguez
- Department of Biology and Chemistry, Liberty University, 1971 University Blvd, Lynchburg, VA, 24502, USA
| | - Emma Mohler
- Department of Biology and Chemistry, Liberty University, 1971 University Blvd, Lynchburg, VA, 24502, USA
| | - Levi Mailloux
- Department of Biology and Chemistry, Liberty University, 1971 University Blvd, Lynchburg, VA, 24502, USA
| | - Sarah Melton
- Department of Biology and Chemistry, Liberty University, 1971 University Blvd, Lynchburg, VA, 24502, USA
| | - Dajeong Jung
- Department of Biology and Chemistry, Liberty University, 1971 University Blvd, Lynchburg, VA, 24502, USA
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5
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Multi-Omics Analysis of Multiple Glucose-Sensing Receptor Systems in Yeast. Biomolecules 2022; 12:biom12020175. [PMID: 35204676 PMCID: PMC8961648 DOI: 10.3390/biom12020175] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/14/2022] [Accepted: 01/18/2022] [Indexed: 12/13/2022] Open
Abstract
The yeast Saccharomyces cerevisiae has long been used to produce alcohol from glucose and other sugars. While much is known about glucose metabolism, relatively little is known about the receptors and signaling pathways that indicate glucose availability. Here, we compare the two glucose receptor systems in S. cerevisiae. The first is a heterodimer of transporter-like proteins (transceptors), while the second is a seven-transmembrane receptor coupled to a large G protein (Gpa2) that acts in coordination with two small G proteins (Ras1 and Ras2). Through comprehensive measurements of glucose-dependent transcription and metabolism, we demonstrate that the two receptor systems have distinct roles in glucose signaling: the G-protein-coupled receptor directs carbohydrate and energy metabolism, while the transceptors regulate ancillary processes such as ribosome, amino acids, cofactor and vitamin metabolism. The large G-protein transmits the signal from its cognate receptor, while the small G-protein Ras2 (but not Ras1) integrates responses from both receptor pathways. Collectively, our analysis reveals the molecular basis for glucose detection and the earliest events of glucose-dependent signal transduction in yeast.
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6
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Tian M, Li Q, Liu Y, Zheng P, Li D, Zhao Y, Wang B, Li C, Wang J, Gao P, Tang Q, Zhang X, Wu H. Relationship between delayed luminescence emission and mitochondrial status in Saccharomyces cerevisiae. Sci Rep 2022; 12:394. [PMID: 35013471 PMCID: PMC8748773 DOI: 10.1038/s41598-021-04290-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 12/20/2021] [Indexed: 11/09/2022] Open
Abstract
Delayed luminescence (DL) is gradually used in various detection of biological systems as a rapid detection technique, however, its biological mechanism was still not clear. In this study, a new model of DL detection system for liquid biological samples is established to investigate the DL emission of Saccharomyces cerevisiae cells cultured in different glucose concentrations. We analyzed the relationship between the DL emission and cell growth, cell vitality, mitochondrial morphology, mitochondrial DNA (mtDNA) copy number, adenosine triphosphate (ATP), oxygen consumption rate (OCR), as well as mitochondria membrane potential (MMP) in S. cerevisiae cells cultured with 0.01, 0.05, 0.15, 3, 10 and 20 g/L glucose respectively. It was found that the DL emission had strong correlation with mitochondrial morphology, OCR, and MMP. The results suggested that DL is an indicator of mitochondria status under different glucose supply conditions, and may be an effective method to detect mitochondrial metabolism related disorders.
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Affiliation(s)
- Miao Tian
- ENNOVA Institute of Life Science and Technology, ENN Group, South District of ENN Industrial Park, Langfang, 065001, Hebei, China
| | - Qing Li
- ENNOVA Institute of Life Science and Technology, ENN Group, South District of ENN Industrial Park, Langfang, 065001, Hebei, China
| | - Yang Liu
- ENNOVA Institute of Life Science and Technology, ENN Group, South District of ENN Industrial Park, Langfang, 065001, Hebei, China
| | - Peng Zheng
- ENNOVA Institute of Life Science and Technology, ENN Group, South District of ENN Industrial Park, Langfang, 065001, Hebei, China
| | - Danyu Li
- ENNOVA Institute of Life Science and Technology, ENN Group, South District of ENN Industrial Park, Langfang, 065001, Hebei, China
| | - Yanpeng Zhao
- ENNOVA Institute of Life Science and Technology, ENN Group, South District of ENN Industrial Park, Langfang, 065001, Hebei, China
| | - Bing Wang
- ENNOVA Institute of Life Science and Technology, ENN Group, South District of ENN Industrial Park, Langfang, 065001, Hebei, China
| | - Chenhao Li
- ENNOVA Institute of Life Science and Technology, ENN Group, South District of ENN Industrial Park, Langfang, 065001, Hebei, China
| | - Jing Wang
- ENNOVA Institute of Life Science and Technology, ENN Group, South District of ENN Industrial Park, Langfang, 065001, Hebei, China
| | - Peng Gao
- ENNOVA Institute of Life Science and Technology, ENN Group, South District of ENN Industrial Park, Langfang, 065001, Hebei, China
| | - Qing Tang
- ENNOVA Institute of Life Science and Technology, ENN Group, South District of ENN Industrial Park, Langfang, 065001, Hebei, China
| | - Xiaochun Zhang
- ENNOVA Institute of Life Science and Technology, ENN Group, South District of ENN Industrial Park, Langfang, 065001, Hebei, China
| | - Hong Wu
- ENNOVA Institute of Life Science and Technology, ENN Group, South District of ENN Industrial Park, Langfang, 065001, Hebei, China.
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Wang CF, Han GL, Yang ZR, Li YX, Wang BS. Plant Salinity Sensors: Current Understanding and Future Directions. FRONTIERS IN PLANT SCIENCE 2022; 13:859224. [PMID: 35463402 PMCID: PMC9022007 DOI: 10.3389/fpls.2022.859224] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 03/14/2022] [Indexed: 05/07/2023]
Abstract
Salt stress is a major limiting factor for plant growth and crop yield. High salinity causes osmotic stress followed by ionic stress, both of which disturb plant growth and metabolism. Understanding how plants perceive salt stress will help efforts to improve salt tolerance and ameliorate the effect of salt stress on crop growth. Various sensors and receptors in plants recognize osmotic and ionic stresses and initiate signal transduction and adaptation responses. In the past decade, much progress has been made in identifying the sensors involved in salt stress. Here, we review current knowledge of osmotic sensors and Na+ sensors and their signal transduction pathways, focusing on plant roots under salt stress. Based on bioinformatic analyses, we also discuss possible structures and mechanisms of the candidate sensors. With the rapid decline of arable land, studies on salt-stress sensors and receptors in plants are critical for the future of sustainable agriculture in saline soils. These studies also broadly inform our overall understanding of stress signaling in plants.
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Brink DP, Borgström C, Persson VC, Ofuji Osiro K, Gorwa-Grauslund MF. D-Xylose Sensing in Saccharomyces cerevisiae: Insights from D-Glucose Signaling and Native D-Xylose Utilizers. Int J Mol Sci 2021; 22:12410. [PMID: 34830296 PMCID: PMC8625115 DOI: 10.3390/ijms222212410] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 11/11/2021] [Accepted: 11/12/2021] [Indexed: 11/17/2022] Open
Abstract
Extension of the substrate range is among one of the metabolic engineering goals for microorganisms used in biotechnological processes because it enables the use of a wide range of raw materials as substrates. One of the most prominent examples is the engineering of baker's yeast Saccharomyces cerevisiae for the utilization of d-xylose, a five-carbon sugar found in high abundance in lignocellulosic biomass and a key substrate to achieve good process economy in chemical production from renewable and non-edible plant feedstocks. Despite many excellent engineering strategies that have allowed recombinant S. cerevisiae to ferment d-xylose to ethanol at high yields, the consumption rate of d-xylose is still significantly lower than that of its preferred sugar d-glucose. In mixed d-glucose/d-xylose cultivations, d-xylose is only utilized after d-glucose depletion, which leads to prolonged process times and added costs. Due to this limitation, the response on d-xylose in the native sugar signaling pathways has emerged as a promising next-level engineering target. Here we review the current status of the knowledge of the response of S. cerevisiae signaling pathways to d-xylose. To do this, we first summarize the response of the native sensing and signaling pathways in S. cerevisiae to d-glucose (the preferred sugar of the yeast). Using the d-glucose case as a point of reference, we then proceed to discuss the known signaling response to d-xylose in S. cerevisiae and current attempts of improving the response by signaling engineering using native targets and synthetic (non-native) regulatory circuits.
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Affiliation(s)
- Daniel P. Brink
- Applied Microbiology, Department of Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden; (C.B.); (V.C.P.); (K.O.O.)
| | - Celina Borgström
- Applied Microbiology, Department of Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden; (C.B.); (V.C.P.); (K.O.O.)
- BioZone Centre for Applied Bioscience and Bioengineering, Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College St., Toronto, ON M5S 3E5, Canada
| | - Viktor C. Persson
- Applied Microbiology, Department of Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden; (C.B.); (V.C.P.); (K.O.O.)
| | - Karen Ofuji Osiro
- Applied Microbiology, Department of Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden; (C.B.); (V.C.P.); (K.O.O.)
- Genetics and Biotechnology Laboratory, Embrapa Agroenergy, Brasília 70770-901, DF, Brazil
| | - Marie F. Gorwa-Grauslund
- Applied Microbiology, Department of Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden; (C.B.); (V.C.P.); (K.O.O.)
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9
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Enhanced β-carotene production by overexpressing the DID2 gene, a subunit of ESCRT complex, in engineered Yarrowia lipolytica. Biotechnol Lett 2021; 43:1799-1807. [PMID: 34160748 DOI: 10.1007/s10529-021-03150-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 05/21/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVE β-Carotene has been widely used in the food and feed industry and has significant commercial value. This study aimed to increase the β-carotene production in engineered Yarrowia lipolytica by optimizing the host metabolic network. The DID2 gene, a subunit of the endosomal sorting complex required for transport (ESCRT), was integrated into a β-carotene producing strain. RESULTS The β-carotene production was increased by 260%, and the biomass increased by 10% for engineered Y. lipolytica. Meanwhile, DID2 elevated the mRNA level and protein level of the genes in the β-carotene synthesis pathway, then increased precursors (FPP, Lycopene) utilization. DID2 also increased the mRNA level of the genes in the glucose pathway, pentose phosphate pathway, and tricarboxylic acid cycle and promoted glucose utilization and cofactors consumption. CONCLUSION The ESCRT protein complex subunit, DID2, improved β-carotene production in engineered Y. lipolytica and beneficial to glucose utilization and cofactors consumption. This study provided new finding of the DID2 gene's function and it mostly could be used for many other natural product productions.
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Breia R, Conde A, Badim H, Fortes AM, Gerós H, Granell A. Plant SWEETs: from sugar transport to plant-pathogen interaction and more unexpected physiological roles. PLANT PHYSIOLOGY 2021; 186:836-852. [PMID: 33724398 PMCID: PMC8195505 DOI: 10.1093/plphys/kiab127] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 03/05/2021] [Indexed: 05/19/2023]
Abstract
Sugars Will Eventually be Exported Transporters (SWEETs) have important roles in numerous physiological mechanisms where sugar efflux is critical, including phloem loading, nectar secretion, seed nutrient filling, among other less expected functions. They mediate low affinity and high capacity transport, and in angiosperms this family is composed by 20 paralogs on average. As SWEETs facilitate the efflux of sugars, they are highly susceptible to hijacking by pathogens, making them central players in plant-pathogen interaction. For instance, several species from the Xanthomonas genus are able to upregulate the transcription of SWEET transporters in rice (Oryza sativa), upon the secretion of transcription-activator-like effectors. Other pathogens, such as Botrytis cinerea or Erysiphe necator, are also capable of increasing SWEET expression. However, the opposite behavior has been observed in some cases, as overexpression of the tonoplast AtSWEET2 during Pythium irregulare infection restricted sugar availability to the pathogen, rendering plants more resistant. Therefore, a clear-cut role for SWEET transporters during plant-pathogen interactions has so far been difficult to define, as the metabolic signatures and their regulatory nodes, which decide the susceptibility or resistance responses, remain poorly understood. This fuels the still ongoing scientific question: what roles can SWEETs play during plant-pathogen interaction? Likewise, the roles of SWEET transporters in response to abiotic stresses are little understood. Here, in addition to their relevance in biotic stress, we also provide a small glimpse of SWEETs importance during plant abiotic stress, and briefly debate their importance in the particular case of grapevine (Vitis vinifera) due to its socioeconomic impact.
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Affiliation(s)
- Richard Breia
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Braga 4710-057, Portugal
- Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Trás-os-Montes e Alto Douro, Vila Real 5001-801, Portugal
| | - Artur Conde
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Braga 4710-057, Portugal
- Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Trás-os-Montes e Alto Douro, Vila Real 5001-801, Portugal
- Author for communication:
| | - Hélder Badim
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Braga 4710-057, Portugal
| | - Ana Margarida Fortes
- Lisbon Science Faculty, BioISI, University of Lisbon, Campo Grande, Lisbon 1749-016, Portugal
| | - Hernâni Gerós
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Braga 4710-057, Portugal
- Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Trás-os-Montes e Alto Douro, Vila Real 5001-801, Portugal
- Centre of Biological Engineering (CEB), Department of Engineering, University of Minho, Braga 4710-057, Portugal
| | - Antonio Granell
- Institute of Molecular and Cellular Biology of Plants, Spanish National Research Council (CSIC), Polytechnic University of Valencia, Valencia 46022, Spain
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Drew D, North RA, Nagarathinam K, Tanabe M. Structures and General Transport Mechanisms by the Major Facilitator Superfamily (MFS). Chem Rev 2021; 121:5289-5335. [PMID: 33886296 PMCID: PMC8154325 DOI: 10.1021/acs.chemrev.0c00983] [Citation(s) in RCA: 157] [Impact Index Per Article: 52.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Indexed: 12/12/2022]
Abstract
The major facilitator superfamily (MFS) is the largest known superfamily of secondary active transporters. MFS transporters are responsible for transporting a broad spectrum of substrates, either down their concentration gradient or uphill using the energy stored in the electrochemical gradients. Over the last 10 years, more than a hundred different MFS transporter structures covering close to 40 members have provided an atomic framework for piecing together the molecular basis of their transport cycles. Here, we summarize the remarkable promiscuity of MFS members in terms of substrate recognition and proton coupling as well as the intricate gating mechanisms undergone in achieving substrate translocation. We outline studies that show how residues far from the substrate binding site can be just as important for fine-tuning substrate recognition and specificity as those residues directly coordinating the substrate, and how a number of MFS transporters have evolved to form unique complexes with chaperone and signaling functions. Through a deeper mechanistic description of glucose (GLUT) transporters and multidrug resistance (MDR) antiporters, we outline novel refinements to the rocker-switch alternating-access model, such as a latch mechanism for proton-coupled monosaccharide transport. We emphasize that a full understanding of transport requires an elucidation of MFS transporter dynamics, energy landscapes, and the determination of how rate transitions are modulated by lipids.
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Affiliation(s)
- David Drew
- Department
of Biochemistry and Biophysics, Stockholm
University, SE 106 91 Stockholm, Sweden
| | - Rachel A. North
- Department
of Biochemistry and Biophysics, Stockholm
University, SE 106 91 Stockholm, Sweden
| | - Kumar Nagarathinam
- Center
of Structural and Cell Biology in Medicine, Institute of Biochemistry, University of Lübeck, D-23538, Lübeck, Germany
| | - Mikio Tanabe
- Structural
Biology Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Oho 1-1, Tsukuba, Ibaraki 305-0801, Japan
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12
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Raina M, Kumar A, Yadav N, Kumari S, Yusuf MA, Mustafiz A, Kumar D. StCaM2, a calcium binding protein, alleviates negative effects of salinity and drought stress in tobacco. PLANT MOLECULAR BIOLOGY 2021; 106:85-108. [PMID: 33629224 DOI: 10.1007/s11103-021-01131-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 02/09/2021] [Indexed: 05/20/2023]
Abstract
KEY MESSAGE Overexpression of StCaM2 in tobacco promotes plant growth and confers increased salinity and drought tolerance by enhancing the photosynthetic efficiency, ROS scavenging, and recovery from membrane injury. Calmodulins (CaMs) are important Ca2+ sensors that interact with effector proteins and drive a network of signal transduction pathways involved in regulating the growth and developmental pattern of plants under stress. Herein, using in silico analysis, we identified 17 CaM isoforms (StCaM) in potato. Expression profiling revealed different temporal and spatial expression patterns of these genes, which were modulated under abiotic stress. Among the identified StCaM genes, StCaM2 was found to have the largest number of abiotic stress responsive promoter elements. In addition, StCaM2 was upregulated in response to some of the selected abiotic stress in potato tissues. Overexpression of StCaM2 in transgenic tobacco plants enhanced their tolerance to salinity and drought stress. Accumulation of reactive oxygen species was remarkably decreased in transgenic lines compared to that in wild type plants. Chlorophyll a fluorescence analysis suggested better performance of photosystem II in transgenic plants under stress compared to that in wild type plants. The increase in salinity stress tolerance in StCaM2-overexpressing plants was also associated with a favorable K+/Na+ ratio. The enhanced tolerance to abiotic stresses correlated with the increase in the activities of anti-oxidative enzymes in transgenic tobacco plants. Overall, our results suggest that StCaM2 can be a novel candidate for conferring salt and drought tolerance in plants.
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Affiliation(s)
- Meenakshi Raina
- Department of Botany, Central University of Jammu, Rahya-Suchani (Bagla), Dist- Samba, Jammu and Kashmir, 181143, India
| | - Ashish Kumar
- Plant Molecular Biology Laboratory, Faculty of Life Sciences and Biotechnology, South Asian University, Akbar Bhawan, Chanakyapuri, New Delhi, 110021, India
| | - Nikita Yadav
- Plant Molecular Biology Laboratory, Faculty of Life Sciences and Biotechnology, South Asian University, Akbar Bhawan, Chanakyapuri, New Delhi, 110021, India
| | - Sumita Kumari
- Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, Jammu and Kashmir, India
| | - Mohd Aslam Yusuf
- Department of Bioengineering, Integral University, Dasauli, Kursi Road, Lucknow, 226026, India
| | - Ananda Mustafiz
- Plant Molecular Biology Laboratory, Faculty of Life Sciences and Biotechnology, South Asian University, Akbar Bhawan, Chanakyapuri, New Delhi, 110021, India.
| | - Deepak Kumar
- Department of Botany, Central University of Jammu, Rahya-Suchani (Bagla), Dist- Samba, Jammu and Kashmir, 181143, India.
- Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, Uttar Pradesh, India.
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13
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LaBella AL, Opulente DA, Steenwyk JL, Hittinger CT, Rokas A. Signatures of optimal codon usage in metabolic genes inform budding yeast ecology. PLoS Biol 2021; 19:e3001185. [PMID: 33872297 PMCID: PMC8084343 DOI: 10.1371/journal.pbio.3001185] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 04/29/2021] [Accepted: 03/15/2021] [Indexed: 02/06/2023] Open
Abstract
Reverse ecology is the inference of ecological information from patterns of genomic variation. One rich, heretofore underutilized, source of ecologically relevant genomic information is codon optimality or adaptation. Bias toward codons that match the tRNA pool is robustly associated with high gene expression in diverse organisms, suggesting that codon optimization could be used in a reverse ecology framework to identify highly expressed, ecologically relevant genes. To test this hypothesis, we examined the relationship between optimal codon usage in the classic galactose metabolism (GAL) pathway and known ecological niches for 329 species of budding yeasts, a diverse subphylum of fungi. We find that optimal codon usage in the GAL pathway is positively correlated with quantitative growth on galactose, suggesting that GAL codon optimization reflects increased capacity to grow on galactose. Optimal codon usage in the GAL pathway is also positively correlated with human-associated ecological niches in yeasts of the CUG-Ser1 clade and with dairy-associated ecological niches in the family Saccharomycetaceae. For example, optimal codon usage of GAL genes is greater than 85% of all genes in the genome of the major human pathogen Candida albicans (CUG-Ser1 clade) and greater than 75% of genes in the genome of the dairy yeast Kluyveromyces lactis (family Saccharomycetaceae). We further find a correlation between optimization in the GALactose pathway genes and several genes associated with nutrient sensing and metabolism. This work suggests that codon optimization harbors information about the metabolic ecology of microbial eukaryotes. This information may be particularly useful for studying fungal dark matter-species that have yet to be cultured in the lab or have only been identified by genomic material.
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Affiliation(s)
- Abigail Leavitt LaBella
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Dana A. Opulente
- Department of Biology, Villanova University, Villanova, Pennsylvania, United States of America
| | - Jacob L. Steenwyk
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Chris Todd Hittinger
- Laboratory of Genetics, DOE Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, Center for Genomic Science Innovation, J.F. Crow Institute for the Study of Evolution, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
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14
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Plug-and-socket mechanisms in nutrient sensing by lysosomal amino acid transporters. Proc Natl Acad Sci U S A 2021; 118:2102173118. [PMID: 33723009 DOI: 10.1073/pnas.2102173118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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15
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Glucose regulation of the paralogous glucose sensing receptors Rgt2 and Snf3 of the yeast Saccharomyces cerevisiae. Biochim Biophys Acta Gen Subj 2021; 1865:129881. [PMID: 33617932 DOI: 10.1016/j.bbagen.2021.129881] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/08/2021] [Accepted: 02/16/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND The yeast Saccharomyces cerevisiae senses extracellular glucose levels through the two paralogous glucose sensing receptors Rgt2 and Snf3, which appear to sense high and low levels of glucose, respectively. METHODS Western blotting and qRT-PCR were used to determine expression levels of the glucose sensing receptors. RESULTS Rgt2 and Snf3 are expressed at different levels in response to different glucose concentrations. SNF3 expression is repressed by high glucose, whereas Rgt2 is turned over in response to glucose starvation. As a result, Rgt2 is predominant in cells grown on high glucose, whereas Snf3 is more abundant of the two paralogs in cells grown on low glucose. When expressed from a constitutive promoter, however, Snf3 behaves like Rgt2, being able to transduce the high glucose signal that induces HXT1 expression. Of note, constitutively active Rgt2 does not undergo glucose starvation-induced endocytic downregulation, whereas signaling defective Rgt2 is constitutively targeted for vacuolar degradation. These results suggest that glucose protects Rgt2 from endocytic degradation and reveal a previously unknown function of glucose as a signaling molecule that regulates the stability of its receptor. CONCLUSION Expression of Rgt2 and Snf3 is regulated by different mechanisms: Rgt2 expression is highly regulated at the level of protein stability; Snf3 expression is mainly regulated at the level of transcription. GENERAL SIGNIFICANCE The difference in the roles of Rgt2 and Snf3 in glucose sensing is a consequence of their cell surface abundance rather than a result of the two paralogous proteins having different functions.
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16
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Choi JH, Lim YS, Kim MK, Bae SH. Analyses of DNA double-strand break repair pathways in tandem arrays of HXT genes of Saccharomyces cerevisiae. J Microbiol 2020; 58:957-966. [PMID: 33125670 DOI: 10.1007/s12275-020-0461-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 09/15/2020] [Accepted: 09/21/2020] [Indexed: 01/02/2023]
Abstract
Eukaryotic genomes contain numerous homologous repeat sequences including redundant genes with divergent homology that can be potential recombination targets. Recombination between divergent sequences is rare but poses a substantial threat to genome stability. The hexose transporter (HXT) gene family shares high sequence similarities at both protein and DNA levels, and some members are placed close together in tandem arrays. In this study, we show that spontaneous interstitial deletions occur at significantly high rates in HXT gene clusters, resulting in chimeric HXT sequences that contain a single junction point. We also observed that DNA double-strand breaks created between HXT genes produce primarily interstitial deletions, whereas internal cleavage of the HXT gene resulted in gene conversions as well as deletion products. Interestingly, interstitial deletions were less constrained by sequence divergence than gene conversion. Moreover, recombination-defective mutations differentially affected the survival frequency. Mutations that impair single-strand annealing (SSA) pathway greatly reduced the survival frequency by 10-1,000-fold, whereas disruption of Rad51-dependent homologous recombination exhibited only modest reduction. Our results indicate that recombination in the tandemly repeated HXT genes occurs primarily via SSA pathway.
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Affiliation(s)
- Ju-Hee Choi
- Department of Biological Sciences, College of Natural Science, Inha University, Incheon, 22212, Republic of Korea
| | - Ye-Seul Lim
- Department of Biological Sciences, College of Natural Science, Inha University, Incheon, 22212, Republic of Korea
| | - Min-Ku Kim
- Department of Biological Sciences, College of Natural Science, Inha University, Incheon, 22212, Republic of Korea
| | - Sung-Ho Bae
- Department of Biological Sciences, College of Natural Science, Inha University, Incheon, 22212, Republic of Korea.
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17
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Zhao W, Tian S, Huang L, Liu K, Dong L. The review of Lab-on-PCB for biomedical application. Electrophoresis 2020; 41:1433-1445. [PMID: 31945803 DOI: 10.1002/elps.201900444] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 01/08/2020] [Accepted: 01/10/2020] [Indexed: 12/29/2022]
Abstract
Prevention of infectious diseases, diagnosis of diseases, and determination of treatment options all rely on biosensors to detect and analyze biomarkers, which are usually divided into four parts: cell analysis, biochemical analysis, immunoassay, and molecular diagnosis. However, traditional biosensing devices are expensive, bulky, and require a lot of time to detect, which also limited its application in resource-limited areas. In recent years, Lab-on-PCB, which combines biosensing technology and PCB technology, has been widely used in biomedical applications due to its high integration, personalized design, and easy mass production. Among these Lab-on-PCB sensing devices, the PCB circuit plays an important role. It can be directly used as a resistance sensor to count cells, and also used as a control device to automatically control the detection device. Flexible PCBs can be used to make wearable medical biosensors. In addition, due to the high degree of integration of the PCB circuit, Lab-on-PCB can perform multiple inspections on the same platform, which reduces the inspection time equivalently. Therefore, in this review paper, we discuss the application of Lab-on-PCB in four analysis methods of cell analysis, biochemical analysis, immunoassay, and molecular diagnosis, and give some suggestions for improvement and future development trends at the end.
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Affiliation(s)
- Wenhao Zhao
- School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu, P.R. China
| | - Shulin Tian
- School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu, P.R. China
| | - Lei Huang
- School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu, P.R. China
| | - Ke Liu
- School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu, P.R. China
| | - Lijuan Dong
- School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu, P.R. China
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18
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Simulating Extracellular Glucose Signals Enhances Xylose Metabolism in Recombinant Saccharomyces cerevisiae. Microorganisms 2020; 8:microorganisms8010100. [PMID: 31936831 PMCID: PMC7022881 DOI: 10.3390/microorganisms8010100] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Revised: 12/30/2019] [Accepted: 01/08/2020] [Indexed: 12/24/2022] Open
Abstract
Efficient utilization of both glucose and xylose from lignocellulosic biomass would be economically beneficial for biofuel production. Recombinant Saccharomyces cerevisiae strains with essential genes and metabolic networks for xylose metabolism can ferment xylose; however, the efficiency of xylose fermentation is much lower than that of glucose, the preferred carbon source of yeast. Implications from our previous work suggest that activation of the glucose sensing system may benefit xylose metabolism. Here, we show that deleting cAMP phosphodiesterase genes PDE1 and PDE2 increased PKA activity of strains, and consequently, increased xylose utilization. Compared to the wild type strain, the specific xylose consumption rate (rxylose) of the pde1Δ pde2Δ mutant strains increased by 50%; the specific ethanol-producing rate (rethanol) of the strain increased by 70%. We also show that HXT1 and HXT2 transcription levels slightly increased when xylose was present. We also show that HXT1 and HXT2 transcription levels slightly increased when xylose was present. Deletion of either RGT2 or SNF3 reduced expression of HXT1 in strains cultured in 1 g L−1 xylose, which suggests that xylose can bind both Snf3 and Rgt2 and slightly alter their conformations. Deletion of SNF3 significantly weakened the expression of HXT2 in the yeast cultured in 40 g L−1 xylose, while deletion of RGT2 did not weaken expression of HXT2, suggesting that S. cerevisiae mainly depends on Snf3 to sense a high concentration of xylose (40 g L−1). Finally, we show that deletion of Rgt1, increased rxylose by 24% from that of the control. Our findings indicate how S. cerevisiae may respond to xylose and this study provides novel targets for further engineering of xylose-fermenting strains.
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19
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Zhou YR, Song XY, Li Y, Shi JC, Shi WL, Chen XL, Liu WF, Liu XM, Zhang WX, Zhang YZ. Enhancing peptaibols production in the biocontrol fungus Trichoderma longibrachiatum SMF2 by elimination of a putative glucose sensor. Biotechnol Bioeng 2019; 116:3030-3040. [PMID: 31403179 DOI: 10.1002/bit.27138] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 07/27/2019] [Accepted: 08/02/2019] [Indexed: 12/17/2022]
Abstract
Trichoderma spp. are main producers of peptide antibiotics known as peptaibols. While peptaibols have been shown to possess a range of biological activities, molecular understanding of the regulation of their production is largely unclear, which hampers the production improvement through genetic engineering. Here, we demonstrated that the orthologue of glucose sensors in the outstanding biocontrol fungus Trichoderma longibrachiatum SMF2, TlSTP1, participates in the regulation of peptaibols production. Deletion of Tlstp1 markedly impaired hyphal growth and conidiation, but significantly increased peptaibols yield by 5-fold for Trichokonins A and 2.6-fold for Trichokonins B. Quantitative real-time polymerase chain reaction analyses showed that the increased peptaibols production occurs at the transcriptional levels of the two nonribosomal peptide synthetase encoding genes, tlx1 and tlx2. Transcriptome analyses of the wild type and the Tlstp1 mutant strains indicated that TlSTP1 exerts a regulatory effect on a set of genes that are involved in a number of metabolic and cellular processes, including synthesis of several other secondary metabolites. These results suggest an important role of TlSTP1 in the regulation of vegetative growth and peptaibols production in T. longibrachiatum SMF2 and provide insights into construction of peptaibol-hyperproducing strains through genetic engineering.
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Affiliation(s)
- Yan-Rong Zhou
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Xiao-Yan Song
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Yue Li
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Jin-Chao Shi
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Wei-Ling Shi
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Xiu-Lan Chen
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Wei-Feng Liu
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Xiang-Mei Liu
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Wei-Xin Zhang
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Yu-Zhong Zhang
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,College of Marine Life Sciences, Ocean University of China, Qingdao, China
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20
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Zhang P, Chen Q, Fu G, Xia L, Hu X. Regulation and metabolic engineering strategies for permeases of Saccharomyces cerevisiae. World J Microbiol Biotechnol 2019; 35:112. [PMID: 31286266 DOI: 10.1007/s11274-019-2684-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 06/26/2019] [Indexed: 12/19/2022]
Abstract
Microorganisms have evolved permeases to incorporate various essential nutrients and exclude harmful products, which assists in adaptation to different environmental conditions for survival. As permeases are directly involved in the utilization of and regulatory response to nutrient sources, metabolic engineering of microbial permeases can predictably influence nutrient metabolism and regulation. In this mini-review, we have summarized the mechanisms underlying the general regulation of permeases, and the current advancements and future prospects of metabolic engineering strategies targeting the permeases in Saccharomyces cerevisiae. The different types of permeases and their regulatory mechanisms have been discussed. Furthermore, methods for metabolic engineering of permeases have been highlighted. Understanding the mechanisms via which permeases are meticulously regulated and engineered will not only facilitate research on regulation of global nutrition and yeast metabolic engineering, but can also provide important insights for future studies on the synthesis of valuable products and elimination of harmful substances in S. cerevisiae.
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Affiliation(s)
- Peng Zhang
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, China.,School of Food Science and Technology, Nanchang University, 235 Nanjing East Road, Nanchang, 330047, Jiangxi, China
| | - Qian Chen
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, China.,School of Food Science and Technology, Nanchang University, 235 Nanjing East Road, Nanchang, 330047, Jiangxi, China
| | - Guiming Fu
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, China.,School of Food Science and Technology, Nanchang University, 235 Nanjing East Road, Nanchang, 330047, Jiangxi, China
| | - Linglin Xia
- Department of Software, Nanchang University, Nanchang, 330047, China
| | - Xing Hu
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, China. .,School of Food Science and Technology, Nanchang University, 235 Nanjing East Road, Nanchang, 330047, Jiangxi, China.
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21
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Gómez-Gallego T, Benabdellah K, Merlos MA, Jiménez-Jiménez AM, Alcon C, Berthomieu P, Ferrol N. The Rhizophagus irregularis Genome Encodes Two CTR Copper Transporters That Mediate Cu Import Into the Cytosol and a CTR-Like Protein Likely Involved in Copper Tolerance. FRONTIERS IN PLANT SCIENCE 2019; 10:604. [PMID: 31156674 PMCID: PMC6531763 DOI: 10.3389/fpls.2019.00604] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 04/24/2019] [Indexed: 05/31/2023]
Abstract
Arbuscular mycorrhizal fungi increase fitness of their host plants under Cu deficient and toxic conditions. In this study, we have characterized two Cu transporters of the CTR family (RiCTR1 and RiCTR2) and a CTR-like protein (RiCTR3A) of Rhizophagus irregularis. Functional analyses in yeast revealed that RiCTR1 encodes a plasma membrane Cu transporter, RiCTR2 a vacuolar Cu transporter and RiCTR3A a plasma membrane protein involved in Cu tolerance. RiCTR1 was more highly expressed in the extraradical mycelia (ERM) and RiCTR2 in the intraradical mycelia (IRM). In the ERM, RiCTR1 expression was up-regulated by Cu deficiency and down-regulated by Cu toxicity. RiCTR2 expression increased only in the ERM grown under severe Cu-deficient conditions. These data suggest that RiCTR1 is involved in Cu uptake by the ERM and RiCTR2 in mobilization of vacuolar Cu stores. Cu deficiency decreased mycorrhizal colonization and arbuscule frequency, but increased RiCTR1 and RiCTR2 expression in the IRM, which suggest that the IRM has a high Cu demand. The two alternatively spliced products of RiCTR3, RiCTR3A and RiCTR3B, were more highly expressed in the ERM. Up-regulation of RiCTR3A by Cu toxicity and the yeast complementation assays suggest that RiCTR3A might function as a Cu receptor involved in Cu tolerance.
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Affiliation(s)
- Tamara Gómez-Gallego
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Karim Benabdellah
- Genomic Medicine Department, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, Granada, Spain
| | - Miguel A. Merlos
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Ana M. Jiménez-Jiménez
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Carine Alcon
- Biochimie et Physiologie Moléculaire des Plantes, Institut National de la Recherche Agronomique, Centre National de la Recherche Scientifique, Université de Montpellier, Montpellier SupAgro, Montpellier, France
| | - Pierre Berthomieu
- Biochimie et Physiologie Moléculaire des Plantes, Institut National de la Recherche Agronomique, Centre National de la Recherche Scientifique, Université de Montpellier, Montpellier SupAgro, Montpellier, France
| | - Nuria Ferrol
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
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22
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Rutherford JC, Bahn YS, van den Berg B, Heitman J, Xue C. Nutrient and Stress Sensing in Pathogenic Yeasts. Front Microbiol 2019; 10:442. [PMID: 30930866 PMCID: PMC6423903 DOI: 10.3389/fmicb.2019.00442] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 02/20/2019] [Indexed: 12/23/2022] Open
Abstract
More than 1.5 million fungal species are estimated to live in vastly different environmental niches. Despite each unique host environment, fungal cells sense certain fundamentally conserved elements, such as nutrients, pheromones and stress, for adaptation to their niches. Sensing these extracellular signals is critical for pathogens to adapt to the hostile host environment and cause disease. Hence, dissecting the complex extracellular signal-sensing mechanisms that aid in this is pivotal and may facilitate the development of new therapeutic approaches to control fungal infections. In this review, we summarize the current knowledge on how two important pathogenic yeasts, Candida albicans and Cryptococcus neoformans, sense nutrient availability, such as carbon sources, amino acids, and ammonium, and different stress signals to regulate their morphogenesis and pathogenicity in comparison with the non-pathogenic model yeast Saccharomyces cerevisiae. The molecular interactions between extracellular signals and their respective sensory systems are described in detail. The potential implication of analyzing nutrient and stress-sensing systems in antifungal drug development is also discussed.
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Affiliation(s)
- Julian C Rutherford
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Yong-Sun Bahn
- Department of Biotechnology, Yonsei University, Seoul, South Korea
| | - Bert van den Berg
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, United States
| | - Chaoyang Xue
- Public Health Research Institute, Rutgers University, Newark, NJ, United States.,Department of Molecular Genetics, Biochemistry and Microbiology, Rutgers University, Newark, NJ, United States
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23
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Van Ende M, Wijnants S, Van Dijck P. Sugar Sensing and Signaling in Candida albicans and Candida glabrata. Front Microbiol 2019; 10:99. [PMID: 30761119 PMCID: PMC6363656 DOI: 10.3389/fmicb.2019.00099] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 01/16/2019] [Indexed: 12/30/2022] Open
Abstract
Candida species, such as Candida albicans and Candida glabrata, cause infections at different host sites because they adapt their metabolism depending on the available nutrients. They are able to proliferate under both nutrient-rich and nutrient-poor conditions. This adaptation is what makes these fungi successful pathogens. For both species, sugars are very important nutrients and as the sugar level differs depending on the host niche, different sugar sensing systems must be present. Saccharomyces cerevisiae has been used as a model for the identification of these sugar sensing systems. One of the main carbon sources for yeast is glucose, for which three different pathways have been described. First, two transporter-like proteins, ScSnf3 and ScRgt2, sense glucose levels resulting in the induction of different hexose transporter genes. This situation is comparable in C. albicans and C. glabrata, where sensing of glucose by CaHgt4 and CgSnf3, respectively, also results in hexose transporter gene induction. The second glucose sensing mechanism in S. cerevisiae is via the G-protein coupled receptor ScGpr1, which causes the activation of the cAMP/PKA pathway, resulting in rapid adaptation to the presence of glucose. The main components of this glucose sensing system are also conserved in C. albicans and C. glabrata. However, it seems that the ligand(s) for CaGpr1 are not sugars but lactate and methionine. In C. glabrata, this pathway has not yet been investigated. Finally, the glucose repression pathway ensures repression of respiration and repression of the use of alternative carbon sources. This pathway is not well characterized in Candida species. It is important to note that, apart from glucose, other sugars and sugar-analogs, such as N-acetylglucosamine in the case of C. albicans, are also important carbon sources. In these fungal pathogens, sensing sugars is important for a number of virulence attributes, including adhesion, oxidative stress resistance, biofilm formation, morphogenesis, invasion, and antifungal drug tolerance. In this review, the sugar sensing and signaling mechanisms in these Candida species are compared to S. cerevisiae.
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Affiliation(s)
- Mieke Van Ende
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Department of Biology, KU Leuven, Leuven, Belgium
- VIB-KU Leuven Center for Microbiology, Leuven, Belgium
| | - Stefanie Wijnants
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Department of Biology, KU Leuven, Leuven, Belgium
- VIB-KU Leuven Center for Microbiology, Leuven, Belgium
| | - Patrick Van Dijck
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Department of Biology, KU Leuven, Leuven, Belgium
- VIB-KU Leuven Center for Microbiology, Leuven, Belgium
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24
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Stasyk OG, Denega IO, Padhorny D, Dmytruk KV, Kozakov D, Abbas C, Stasyk OV. Glucose regulation in the methylotrophic yeast Hansenula (Ogataea) polymorpha is mediated by a putative transceptor Gcr1. Int J Biochem Cell Biol 2018; 103:25-34. [PMID: 30081098 DOI: 10.1016/j.biocel.2018.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 07/31/2018] [Accepted: 08/02/2018] [Indexed: 12/26/2022]
Abstract
The HpGcr1, a hexose transporter homologue from the methylotrophic yeast Hansenula (Ogataea) polymorpha, was previously identified as being involved in glucose repression. Intriguingly, potential HpGcr1 orthologues are found only in the genomes of a few yeasts phylogenetically closely related to H. polymorpha, but are absent in all other yeasts. The other closest HpGcr1 homologues are fungal high-affinity glucose symporters or putative transceptors suggesting a possible HpGcr1 origin due to a specific archaic gene retention or via horizontal gene transfer from Eurotiales fungi. Herein we report that, similarly to other yeast non-transporting glucose sensors, the substitution of the conserved arginine residue converts HpGcr1R165K into a constitutively signaling form. Synthesis of HpGcr1R165K in gcr1Δ did not restore glucose transport or repression but instead profoundly impaired growth independent of carbon source used. Simultaneously, gcr1Δ was impaired in transcriptional induction of repressible peroxisomal alcohol oxidase and in growth on methanol. Overexpression of the functional transporter HpHxt1 in gcr1Δ partially restored growth on glucose and glucose repression but did not rescue impaired growth on methanol. Heterologous expression of HpGcr1 in a Saccharomyces cerevisiae hxt-null strain did not restore glucose uptake due to protein mislocalization. However, HpGcr1 overexpression in H. polymorpha led to increased sensitivity to extracellular 2-deoxyglucose, suggesting HpGcr1 is a functional glucose carrier. The combined data suggest that HpGcr1 represents a novel type of yeast glucose transceptor functioning also in the absence of glucose.
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Affiliation(s)
- Olena G Stasyk
- Department of Cell Signaling, Institute of Cell Biology, National Academy of Sciences of Ukraine, Lviv, Ukraine; Department of Biochemistry, Ivan Franko National University of Lviv, Lviv, Ukraine
| | - Iryna O Denega
- Department of Biochemistry, Ivan Franko National University of Lviv, Lviv, Ukraine
| | - Dzmitry Padhorny
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Kostyantyn V Dmytruk
- Department of Molecular Genetics and Biotechnology, Institute of Cell Biology, National Academy of Sciences of Ukraine, Lviv, Ukraine
| | - Dima Kozakov
- Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, New York, USA
| | | | - Oleh V Stasyk
- Department of Cell Signaling, Institute of Cell Biology, National Academy of Sciences of Ukraine, Lviv, Ukraine.
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Genetic Analysis of Signal Generation by the Rgt2 Glucose Sensor of Saccharomyces cerevisiae. G3-GENES GENOMES GENETICS 2018; 8:2685-2696. [PMID: 29954842 PMCID: PMC6071613 DOI: 10.1534/g3.118.200338] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The yeast S. cerevisiae senses glucose through Snf3 and Rgt2, transmembrane proteins that generate an intracellular signal in response to glucose that leads to inhibition of the Rgt1 transcriptional repressor and consequently to derepression of HXT genes encoding glucose transporters. Snf3 and Rgt2 are thought to be glucose receptors because they are similar to glucose transporters. In contrast to glucose transporters, they have unusually long C-terminal tails that bind to Mth1 and Std1, paralogous proteins that regulate function of the Rgt1 transcription factor. We show that the C-terminal tail of Rgt2 is not responsible for its inability to transport glucose. To gain insight into how the glucose sensors generate an intracellular signal, we identified RGT2 mutations that cause constitutive signal generation. Most of the mutations alter evolutionarily-conserved amino acids in the transmembrane spanning regions of Rgt2 that are predicted to be involved in maintaining an outward-facing conformation or to be in the substrate binding site. Our analysis of these mutations suggests they cause Rgt2 to adopt inward-facing or occluded conformations that generate the glucose signal. These results support the idea that Rgt2 and Snf3 are glucose receptors that signal in response to binding of extracellular glucose and inform the basis of their signaling.
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Ohdate T, Omura F, Hatanaka H, Zhou Y, Takagi M, Goshima T, Akao T, Ono E. MAL73, a novel regulator of maltose fermentation, is functionally impaired by single nucleotide polymorphism in sake brewing yeast. PLoS One 2018; 13:e0198744. [PMID: 29894505 PMCID: PMC5997316 DOI: 10.1371/journal.pone.0198744] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 05/24/2018] [Indexed: 11/20/2022] Open
Abstract
For maltose fermentation, budding yeast Saccharomyces cerevisiae operates a mechanism that involves transporters (MALT), maltases (MALS) and regulators (MALR) collectively known as MAL genes. However, functional relevance of MAL genes during sake brewing process remains largely elusive, since sake yeast is cultured under glucose-rich condition achieved by the co-culture partner Aspergillus spp.. Here we isolated an ethyl methane sulfonate (EMS)-mutagenized sake yeast strain exhibiting enhanced maltose fermentation compared to the parental strain. The mutant carried a single nucleotide insertion that leads to the extension of the C-terminal region of a previously uncharacterized MALR gene YPR196W-2, which was renamed as MAL73. Introduction of the mutant allele MAL73L with extended C-terminal region into the parental or other sake yeast strains enhanced the growth rate when fed with maltose as the sole carbon source. In contrast, disruption of endogenous MAL73 in the sake yeasts decreased the maltose fermentation ability of sake yeast, confirming that the original MAL73 functions as a MALR. Importantly, the MAL73L-expressing strain fermented more maltose in practical condition compared to the parental strain during sake brewing process. Our data show that MAL73(L) is a novel MALR gene that regulates maltose fermentation, and has been functionally attenuated in sake yeast by single nucleotide deletion during breeding history. Since the MAL73L-expressing strain showed enhanced ability of maltose fermentation, MAL73L might also be a valuable tool for enhancing maltose fermentation in yeast in general.
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Affiliation(s)
- Takumi Ohdate
- Research Institute, Suntory Global Innovation Center (SIC) Ltd., Seika-cho, Soraku-gun, Kyoto, Japan
- * E-mail:
| | - Fumihiko Omura
- Research Institute, Suntory Global Innovation Center (SIC) Ltd., Seika-cho, Soraku-gun, Kyoto, Japan
| | - Haruyo Hatanaka
- Research Institute, Suntory Global Innovation Center (SIC) Ltd., Seika-cho, Soraku-gun, Kyoto, Japan
| | - Yan Zhou
- National Research Institute of Brewing, Higashihiroshima, Hiroshima, Japan
| | - Masami Takagi
- National Research Institute of Brewing, Higashihiroshima, Hiroshima, Japan
| | - Tetsuya Goshima
- National Research Institute of Brewing, Higashihiroshima, Hiroshima, Japan
| | - Takeshi Akao
- National Research Institute of Brewing, Higashihiroshima, Hiroshima, Japan
| | - Eiichiro Ono
- Research Institute, Suntory Global Innovation Center (SIC) Ltd., Seika-cho, Soraku-gun, Kyoto, Japan
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Mitochondrial Voltage-Dependent Anion Channel Protein Por1 Positively Regulates the Nuclear Localization of Saccharomyces cerevisiae AMP-Activated Protein Kinase. mSphere 2018; 3:mSphere00482-17. [PMID: 29359182 PMCID: PMC5760747 DOI: 10.1128/msphere.00482-17] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 12/03/2017] [Indexed: 01/06/2023] Open
Abstract
AMP-activated protein kinases (AMPKs) sense energy limitation and regulate transcription and metabolism in eukaryotes from yeast to humans. In mammals, AMPK responds to increased AMP-to-ATP or ADP-to-ATP ratios and is implicated in diabetes, heart disease, and cancer. Mitochondria produce ATP and are generally thought to downregulate AMPK. Indeed, some antidiabetic drugs activate AMPK by affecting mitochondrial respiration. ATP release from mitochondria is mediated by evolutionarily conserved proteins known as voltage-dependent anion channels (VDACs). One would therefore expect VDACs to serve as negative regulators of AMPK. However, our experiments in yeast reveal the existence of an opposite relationship. We previously showed that Saccharomyces cerevisiae VDACs Por1 and Por2 positively regulate AMPK/Snf1 catalytic activation. Here, we show that Por1 also plays an important role in promoting AMPK/Snf1 nuclear localization. Our counterintuitive findings could inform research in areas ranging from diabetes to cancer to fungal pathogenesis. Snf1 protein kinase of the yeast Saccharomyces cerevisiae is a member of the highly conserved eukaryotic AMP-activated protein kinase (AMPK) family, which is involved in regulating responses to energy limitation. Under conditions of carbon/energy stress, such as during glucose depletion, Snf1 is catalytically activated and enriched in the nucleus to regulate transcription. Snf1 catalytic activation requires phosphorylation of its conserved activation loop threonine (Thr210) by upstream kinases. Catalytic activation is also a prerequisite for Snf1’s subsequent nuclear enrichment, a process that is mediated by Gal83, one of three alternate β-subunits of the Snf1 kinase complex. We previously reported that the mitochondrial voltage-dependent anion channel (VDAC) proteins Por1 and Por2 play redundant roles in promoting Snf1 catalytic activation by Thr210 phosphorylation. Here, we show that the por1Δ mutation alone, which by itself does not affect Snf1 Thr210 phosphorylation, causes defects in Snf1 and Gal83 nuclear enrichment and Snf1’s ability to stimulate transcription. We present evidence that Por1 promotes Snf1 nuclear enrichment by promoting the nuclear enrichment of Gal83. Overexpression of Por2, which is not believed to have channel activity, can suppress the localization and transcription activation defects of the por1Δ mutant, suggesting that the regulatory role played by Por1 is separable from its channel function. Thus, our findings expand the positive roles of the yeast VDACs in carbon/energy stress signaling upstream of Snf1. Since AMPK/Snf1 and VDAC proteins are conserved in evolution, our findings in yeast may have implications for AMPK regulation in other eukaryotes, including humans. IMPORTANCE AMP-activated protein kinases (AMPKs) sense energy limitation and regulate transcription and metabolism in eukaryotes from yeast to humans. In mammals, AMPK responds to increased AMP-to-ATP or ADP-to-ATP ratios and is implicated in diabetes, heart disease, and cancer. Mitochondria produce ATP and are generally thought to downregulate AMPK. Indeed, some antidiabetic drugs activate AMPK by affecting mitochondrial respiration. ATP release from mitochondria is mediated by evolutionarily conserved proteins known as voltage-dependent anion channels (VDACs). One would therefore expect VDACs to serve as negative regulators of AMPK. However, our experiments in yeast reveal the existence of an opposite relationship. We previously showed that Saccharomyces cerevisiae VDACs Por1 and Por2 positively regulate AMPK/Snf1 catalytic activation. Here, we show that Por1 also plays an important role in promoting AMPK/Snf1 nuclear localization. Our counterintuitive findings could inform research in areas ranging from diabetes to cancer to fungal pathogenesis.
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Osiro KO, Brink DP, Borgström C, Wasserstrom L, Carlquist M, Gorwa-Grauslund MF. Assessing the effect of d-xylose on the sugar signaling pathways of Saccharomyces cerevisiae in strains engineered for xylose transport and assimilation. FEMS Yeast Res 2018; 18:4791530. [DOI: 10.1093/femsyr/fox096] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 12/27/2017] [Indexed: 01/18/2023] Open
Affiliation(s)
- Karen O Osiro
- Applied Microbiology, Department of Chemistry, Lund University, Kemicentrum, Naturvetarvägen 14, Lund 223 62, Sweden
| | - Daniel P Brink
- Applied Microbiology, Department of Chemistry, Lund University, Kemicentrum, Naturvetarvägen 14, Lund 223 62, Sweden
| | - Celina Borgström
- Applied Microbiology, Department of Chemistry, Lund University, Kemicentrum, Naturvetarvägen 14, Lund 223 62, Sweden
| | - Lisa Wasserstrom
- Applied Microbiology, Department of Chemistry, Lund University, Kemicentrum, Naturvetarvägen 14, Lund 223 62, Sweden
| | - Magnus Carlquist
- Applied Microbiology, Department of Chemistry, Lund University, Kemicentrum, Naturvetarvägen 14, Lund 223 62, Sweden
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Yang Y, Guo Y. Elucidating the molecular mechanisms mediating plant salt-stress responses. THE NEW PHYTOLOGIST 2018; 217:523-539. [PMID: 29205383 DOI: 10.1111/nph.14920] [Citation(s) in RCA: 621] [Impact Index Per Article: 103.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 10/11/2017] [Indexed: 05/18/2023]
Abstract
Contents Summary 523 I. Introduction 523 II. Sensing salt stress 524 III. Ion homeostasis regulation 524 IV. Metabolite and cell activity responses to salt stress 527 V. Conclusions and perspectives 532 Acknowledgements 533 References 533 SUMMARY: Excess soluble salts in soil (saline soils) are harmful to most plants. Salt imposes osmotic, ionic, and secondary stresses on plants. Over the past two decades, many determinants of salt tolerance and their regulatory mechanisms have been identified and characterized using molecular genetics and genomics approaches. This review describes recent progress in deciphering the mechanisms controlling ion homeostasis, cell activity responses, and epigenetic regulation in plants under salt stress. Finally, we highlight research areas that require further research to reveal new determinants of salt tolerance in plants.
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Affiliation(s)
- Yongqing Yang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Yan Guo
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
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30
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Rottmann TM, Fritz C, Lauter A, Schneider S, Fischer C, Danzberger N, Dietrich P, Sauer N, Stadler R. Protoplast-Esculin Assay as a New Method to Assay Plant Sucrose Transporters: Characterization of AtSUC6 and AtSUC7 Sucrose Uptake Activity in Arabidopsis Col-0 Ecotype. FRONTIERS IN PLANT SCIENCE 2018; 9:430. [PMID: 29740457 PMCID: PMC5925572 DOI: 10.3389/fpls.2018.00430] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 03/20/2018] [Indexed: 05/20/2023]
Abstract
The best characterized function of sucrose transporters of the SUC family in plants is the uptake of sucrose into the phloem for long-distance transport of photoassimilates. This important step is usually performed by one specific SUC in every species. However, plants possess small families of several different SUCs which are less well understood. Here, we report on the characterization of AtSUC6 and AtSUC7, two members of the SUC family in Arabidopsis thaliana. Heterologous expression in yeast (Saccharomyces cerevisiae) revealed that AtSUC6Col-0 is a high-affinity H+-symporter that mediates the uptake of sucrose and maltose across the plasma membrane at exceptionally low pH values. Reporter gene analyses revealed a strong expression of AtSUC6Col-0 in reproductive tissues, where the protein product might contribute to sugar uptake into pollen tubes and synergid cells. A knockout of AtSUC6 did not interfere with vegetative development or reproduction, which points toward physiological redundancy of AtSUC6Col-0 with other sugar transporters. Reporter gene analyses showed that AtSUC7Col-0 is expressed in roots and pollen tubes and that this sink specific expression of AtSUC7Col-0 is regulated by intragenic regions. Transport activity of AtSUC7Col-0 could not be analyzed in baker's yeast or Xenopus oocytes because the protein was not correctly targeted to the plasma membrane in both heterologous expression systems. Therefore, a novel approach to analyze sucrose transporters in planta was developed. Plasma membrane localized SUCs including AtSUC6Col-0 and also sucrose specific SWEETs were able to mediate transport of the fluorescent sucrose analog esculin in transformed mesophyll protoplasts. In contrast, AtSUC7Col-0 is not able to mediate esculin transport across the plasma membrane which implicates that AtSUC7Col-0 might be a non-functional pseudogene. The novel protoplast assay provides a useful tool for the quick and quantitative analysis of sucrose transporters in an in planta expression system.
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31
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Ries LNA, Beattie S, Cramer RA, Goldman GH. Overview of carbon and nitrogen catabolite metabolism in the virulence of human pathogenic fungi. Mol Microbiol 2017; 107:277-297. [PMID: 29197127 DOI: 10.1111/mmi.13887] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 11/20/2017] [Accepted: 11/23/2017] [Indexed: 12/12/2022]
Abstract
It is estimated that fungal infections, caused most commonly by Candida albicans, Aspergillus fumigatus and Cryptococcus neoformans, result in more deaths annually than malaria or tuberculosis. It has long been hypothesized the fungal metabolism plays a critical role in virulence though specific nutrient sources utilized by human pathogenic fungi in vivo has remained enigmatic. However, the metabolic utilisation of preferred carbon and nitrogen sources, encountered in a host niche-dependent manner, is known as carbon catabolite and nitrogen catabolite repression (CCR, NCR), and has been shown to be important for virulence. Several sensory and uptake systems exist, including carbon and nitrogen source-specific sensors and transporters, that allow scavenging of preferred nutrient sources. Subsequent metabolic utilisation is governed by transcription factors, whose functions and essentiality differ between fungal species. Furthermore, additional factors exist that contribute to the implementation of CCR and NCR. The role of the CCR and NCR-related factors in virulence varies greatly between fungal species and a substantial gap in knowledge exists regarding specific pathways. Further elucidation of carbon and nitrogen metabolism mechanisms is therefore required in a fungal species- and animal model-specific manner in order to screen for targets that are potential candidates for anti-fungal drug development.
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Affiliation(s)
- Laure Nicolas Annick Ries
- Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, Ribeirão Preto, São Paulo, 3900, CEP 14049-900, Brazil
| | - Sarah Beattie
- Department of Microbiology & Immunology, Geisel School of Medicine at Dartmouth, 74 College Street Remsen 213, Hanover, NH 03755, USA
| | - Robert A Cramer
- Department of Microbiology & Immunology, Geisel School of Medicine at Dartmouth, 74 College Street Remsen 213, Hanover, NH 03755, USA
| | - Gustavo H Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café s/n°, Ribeirão Preto, São Paulo, CEP 14040903, Brazil
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32
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Isom DG, Page SC, Collins LB, Kapolka NJ, Taghon GJ, Dohlman HG. Coordinated regulation of intracellular pH by two glucose-sensing pathways in yeast. J Biol Chem 2017; 293:2318-2329. [PMID: 29284676 DOI: 10.1074/jbc.ra117.000422] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 12/22/2017] [Indexed: 12/19/2022] Open
Abstract
The yeast Saccharomyces cerevisiae employs multiple pathways to coordinate sugar availability and metabolism. Glucose and other sugars are detected by a G protein-coupled receptor, Gpr1, as well as a pair of transporter-like proteins, Rgt2 and Snf3. When glucose is limiting, however, an ATP-driven proton pump (Pma1) is inactivated, leading to a marked decrease in cytoplasmic pH. Here we determine the relative contribution of the two sugar-sensing pathways to pH regulation. Whereas cytoplasmic pH is strongly dependent on glucose abundance and is regulated by both glucose-sensing pathways, ATP is largely unaffected and therefore cannot account for the changes in Pma1 activity. These data suggest that the pH is a second messenger of the glucose-sensing pathways. We show further that different sugars differ in their ability to control cellular acidification, in the manner of inverse agonists. We conclude that the sugar-sensing pathways act via Pma1 to invoke coordinated changes in cellular pH and metabolism. More broadly, our findings support the emerging view that cellular systems have evolved the use of pH signals as a means of adapting to environmental stresses such as those caused by hypoxia, ischemia, and diabetes.
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Affiliation(s)
- Daniel G Isom
- From the Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599-7365, .,the Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, Florida 33136, and
| | - Stephani C Page
- From the Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599-7365
| | - Leonard B Collins
- the Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina 27599-7432
| | - Nicholas J Kapolka
- the Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, Florida 33136, and
| | - Geoffrey J Taghon
- the Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, Florida 33136, and
| | - Henrik G Dohlman
- From the Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599-7365,
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33
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Adamczyk M, Szatkowska R. Low RNA Polymerase III activity results in up regulation of HXT2 glucose transporter independently of glucose signaling and despite changing environment. PLoS One 2017; 12:e0185516. [PMID: 28961268 PMCID: PMC5621690 DOI: 10.1371/journal.pone.0185516] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 09/14/2017] [Indexed: 01/13/2023] Open
Abstract
Background Saccharomyces cerevisiae responds to glucose availability in the environment, inducing the expression of the low-affinity transporters and high-affinity transporters in a concentration dependent manner. This cellular decision making is controlled through finely tuned communication between multiple glucose sensing pathways including the Snf1-Mig1, Snf3/Rgt2-Rgt1 (SRR) and cAMP-PKA pathways. Results We demonstrate the first evidence that RNA Polymerase III (RNAP III) activity affects the expression of the glucose transporter HXT2 (RNA Polymerase II dependent—RNAP II) at the level of transcription. Down-regulation of RNAP III activity in an rpc128-1007 mutant results in a significant increase in HXT2 mRNA, which is considered to respond only to low extracellular glucose concentrations. HXT2 expression is induced in the mutant regardless of the growth conditions either at high glucose concentration or in the presence of a non-fermentable carbon source such as glycerol. Using chromatin immunoprecipitation (ChIP), we found an increased association of Rgt1 and Tup1 transcription factors with the highly activated HXT2 promoter in the rpc128-1007 strain. Furthermore, by measuring cellular abundance of Mth1 corepressor, we found that in rpc128-1007, HXT2 gene expression was independent from Snf3/Rgt2-Rgt1 (SRR) signaling. The Snf1 protein kinase complex, which needs to be active for the release from glucose repression, also did not appear perturbed in the mutated strain. Conclusions/Significance These findings suggest that the general activity of RNAP III can indirectly affect the RNAP II transcriptional machinery on the HXT2 promoter when cellular perception transduced via the major signaling pathways, broadly recognized as on/off switch essential to either positive or negative HXT gene regulation, remain entirely intact. Further, Rgt1/Ssn6-Tup1 complex, which has a dual function in gene transcription as a repressor-activator complex, contributes to HXT2 transcriptional activation.
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Affiliation(s)
- Malgorzata Adamczyk
- Institute of Biotechnology, Faculty of Chemistry, Warsaw University of Technology, Warsaw, Poland
- * E-mail:
| | - Roza Szatkowska
- Institute of Biotechnology, Faculty of Chemistry, Warsaw University of Technology, Warsaw, Poland
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34
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Factors Influencing the Production of Sensory Active Substances in Brewer's and Wine Yeast. KVASNY PRUMYSL 2017. [DOI: 10.18832/kp201720] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Ma QJ, Sun MH, Lu J, Liu YJ, Hu DG, Hao YJ. Transcription Factor AREB2 Is Involved in Soluble Sugar Accumulation by Activating Sugar Transporter and Amylase Genes. PLANT PHYSIOLOGY 2017; 174:2348-2362. [PMID: 28600345 PMCID: PMC5543958 DOI: 10.1104/pp.17.00502] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 06/07/2017] [Indexed: 05/18/2023]
Abstract
Sugars play important roles in plant growth and development, crop yield and quality, as well as responses to abiotic stresses. Abscisic acid (ABA) is a multifunctional hormone. However, the exact mechanism by which ABA regulates sugar accumulation is largely unknown in plants. Here, we tested the expression profile of several sugar transporter and amylase genes in response to ABA treatment. MdSUT2 and MdAREB2 were isolated and genetically transformed into apple (Malus domestica) to investigate their roles in ABA-induced sugar accumulation. The MdAREB2 transcription factor was found to bind to the promoters of the sugar transporter and amylase genes and activate their expression. Both MdAREB2 and MdSUT2 transgenic plants produced more soluble sugars than controls. Furthermore, MdAREB2 promoted the accumulation of sucrose and soluble sugars in an MdSUT2-dependent manner. Our results demonstrate that the ABA-responsive transcription factor MdAREB2 directly activates the expression of amylase and sugar transporter genes to promote soluble sugar accumulation, suggesting a mechanism by which ABA regulates sugar accumulation in plants.
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Affiliation(s)
- Qi-Jun Ma
- National Key Laboratory of Crop Biology, National Research Center for Apple Engineering and Technology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong 271018, China
| | - Mei-Hong Sun
- National Key Laboratory of Crop Biology, National Research Center for Apple Engineering and Technology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong 271018, China
| | - Jing Lu
- National Key Laboratory of Crop Biology, National Research Center for Apple Engineering and Technology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong 271018, China
| | - Ya-Jing Liu
- National Key Laboratory of Crop Biology, National Research Center for Apple Engineering and Technology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong 271018, China
| | - Da-Gang Hu
- National Key Laboratory of Crop Biology, National Research Center for Apple Engineering and Technology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong 271018, China
| | - Yu-Jin Hao
- National Key Laboratory of Crop Biology, National Research Center for Apple Engineering and Technology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong 271018, China
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Abstract
To respond to the changing environment, cells must be able to sense external conditions. This is important for many processes including growth, mating, the expression of virulence factors, and several other regulatory effects. Nutrient sensing at the plasma membrane is mediated by different classes of membrane proteins that activate downstream signaling pathways: nontransporting receptors, transceptors, classical and nonclassical G-protein-coupled receptors, and the newly defined extracellular mucin receptors. Nontransporting receptors have the same structure as transport proteins, but have lost the capacity to transport while gaining a receptor function. Transceptors are transporters that also function as a receptor, because they can rapidly activate downstream signaling pathways. In this review, we focus on these four types of fungal membrane proteins. We mainly discuss the sensing mechanisms relating to sugars, ammonium, and amino acids. Mechanisms for other nutrients, such as phosphate and sulfate, are discussed briefly. Because the model yeast Saccharomyces cerevisiae has been the most studied, especially regarding these nutrient-sensing systems, each subsection will commence with what is known in this species.
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Niu C, Payne GA, Woloshuk CP. Involvement of FST1 from Fusarium verticillioides in virulence and transport of inositol. MOLECULAR PLANT PATHOLOGY 2017; 18:695-707. [PMID: 27195938 PMCID: PMC6638204 DOI: 10.1111/mpp.12430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 05/11/2016] [Accepted: 05/13/2016] [Indexed: 06/05/2023]
Abstract
Fumonisin B1 (FB1), a polyketide mycotoxin produced by Fusarium verticillioides during the colonization of maize kernels, is detrimental to human and animal health. FST1 encodes a putative protein with 12 transmembrane domains; however, its function remains unknown. The FST1 gene is highly expressed by the fungus in the endosperm of maize kernels compared with the levels of expression in germ tissues. Previous research has shown that FST1 affects FB1 production, virulence, hydrogen peroxide resistance, hydrophobicity and macroconidia production. Here, we examine the phylogeny of FST1, its expression in a Saccharomyces cerevisiae strain lacking a functional myo-inositol transporter (ITR1) and the effect of amino acid changes in the central loop and C-terminus regions of FST1 on functionality. The results indicate that expression of FST1 in an ITR1 mutant strain restores growth on myo-inositol medium to wild-type levels and restores the inhibitory effects of FB1, suggesting that FST1 can transport both myo-inositol and FB1 into yeast cells. Our results with engineered FST1 also indicate that amino acids in the central loop and C-terminus regions are important for FST1 functionality in both S. cerevisiae and F. verticillioides. Overall, this research has established the first characterized inositol transporter in filamentous fungi and has advanced our knowledge about the global regulatory functions of FST1.
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Affiliation(s)
- Chenxing Niu
- Department of Botany and Plant PathologyPurdue UniversityWest LafayetteIN47907‐2054USA
| | - Gary A. Payne
- Department of Plant PathologyNorth Carolina State UniversityRaleighNC27695‐7567USA
| | - Charles P. Woloshuk
- Department of Botany and Plant PathologyPurdue UniversityWest LafayetteIN47907‐2054USA
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38
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Savir Y, Martynov A, Springer M. Achieving global perfect homeostasis through transporter regulation. PLoS Comput Biol 2017; 13:e1005458. [PMID: 28414718 PMCID: PMC5411106 DOI: 10.1371/journal.pcbi.1005458] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 05/01/2017] [Accepted: 03/16/2017] [Indexed: 01/04/2023] Open
Abstract
Nutrient homeostasis-the maintenance of relatively constant internal nutrient concentrations in fluctuating external environments-is essential to the survival of most organisms. Transcriptional regulation of plasma membrane transporters by internal nutrient concentrations is typically assumed to be the main mechanism by which homeostasis is achieved. While this mechanism is homeostatic we show that it does not achieve global perfect homeostasis-a condition where internal nutrient concentrations are completely independent of external nutrient concentrations for all external nutrient concentrations. We show that the criterion for global perfect homeostasis is that transporter levels must be inversely proportional to net nutrient flux into the cell and that downregulation of active transporters (activity-dependent regulation) is a simple and biologically plausible mechanism that meets this criterion. Activity-dependent transporter regulation creates a trade-off between robustness and efficiency, i.e., the system's ability to withstand perturbation in external nutrients and the transporter production rate needed to maintain homeostasis. Additionally, we show that a system that utilizes both activity-dependent transporter downregulation and regulation of transporter synthesis by internal nutrient levels can create a system that mitigates the shortcomings of each of the individual mechanisms. This analysis highlights the utility of activity-dependent regulation in achieving homeostasis and calls for a re-examination of the mechanisms of regulation of other homeostatic systems.
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Affiliation(s)
- Yonatan Savir
- Department of Physiology, Biophysics and Systems Biology, Faculty of Medicine, Technion, Haifa, Israel
| | - Alexander Martynov
- Center for Data-Intensive Biomedicine and Biotechnology, Skolkovo Institute of Science and Technology, Moscow, Russia
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Michael Springer
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
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Lazar Z, Neuvéglise C, Rossignol T, Devillers H, Morin N, Robak M, Nicaud JM, Crutz-Le Coq AM. Characterization of hexose transporters in Yarrowia lipolytica reveals new groups of Sugar Porters involved in yeast growth. Fungal Genet Biol 2017; 100:1-12. [DOI: 10.1016/j.fgb.2017.01.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 12/21/2016] [Accepted: 01/03/2017] [Indexed: 12/24/2022]
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40
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Wang B, Li J, Gao J, Cai P, Han X, Tian C. Identification and characterization of the glucose dual-affinity transport system in Neurospora crassa: pleiotropic roles in nutrient transport, signaling, and carbon catabolite repression. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:17. [PMID: 28115989 PMCID: PMC5244594 DOI: 10.1186/s13068-017-0705-4] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 01/07/2017] [Indexed: 05/07/2023]
Abstract
BACKGROUND The glucose dual-affinity transport system (low- and high-affinity) is a conserved strategy used by microorganisms to cope with natural fluctuations in nutrient availability in the environment. The glucose-sensing and uptake processes are believed to be tightly associated with cellulase expression regulation in cellulolytic fungi. However, both the identities and functions of the major molecular components of this evolutionarily conserved system in filamentous fungi remain elusive. Here, we systematically identified and characterized the components of the glucose dual-affinity transport system in the model fungus Neurospora crassa. RESULTS Using RNA sequencing coupled with functional transport analyses, we assigned GLT-1 (Km = 18.42 ± 3.38 mM) and HGT-1/-2 (Km = 16.13 ± 0.95 and 98.97 ± 22.02 µM) to the low- and high-affinity glucose transport systems, respectively. The high-affinity transporters hgt-1/-2 complemented a moderate growth defect under high glucose when glt-1 was deleted. Simultaneous deletion of hgt-1/-2 led to extensive derepression of genes for plant cell wall deconstruction in cells grown on cellulose. The suppression by HGT-1/-2 was connected to both carbon catabolite repression (CCR) and the cyclic adenosine monophosphate-protein kinase A pathway. Alteration of a residue conserved across taxa in hexose transporters resulted in a loss of glucose-transporting function, whereas CCR signal transduction was retained, indicating dual functions for HGT-1/-2 as "transceptors." CONCLUSIONS In this study, GLT-1 and HGT-1/-2 were identified as the key components of the glucose dual-affinity transport system, which plays diverse roles in glucose transport and carbon metabolism. Given the wide conservation of the glucose dual-affinity transport system across fungal species, the identification of its components and their pleiotropic roles in this study shed important new light on the molecular basis of nutrient transport, signaling, and plant cell wall degradation in fungi.
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Affiliation(s)
- Bang Wang
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
- School of Ophthalmology and Optometry, Eye Hospital, State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, 325027 China
| | - Jingen Li
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Jingfang Gao
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
- School of Life Sciences, Heilongjiang University, Harbin, 150080 Heilongjiang China
| | - Pengli Cai
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Xiaoyun Han
- School of Life Sciences, Heilongjiang University, Harbin, 150080 Heilongjiang China
| | - Chaoguang Tian
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
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41
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Katz Y, Springer M. Probabilistic adaptation in changing microbial environments. PeerJ 2016; 4:e2716. [PMID: 27994963 PMCID: PMC5160922 DOI: 10.7717/peerj.2716] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 10/25/2016] [Indexed: 11/20/2022] Open
Abstract
Microbes growing in animal host environments face fluctuations that have elements of both randomness and predictability. In the mammalian gut, fluctuations in nutrient levels and other physiological parameters are structured by the host's behavior, diet, health and microbiota composition. Microbial cells that can anticipate environmental fluctuations by exploiting this structure would likely gain a fitness advantage (by adapting their internal state in advance). We propose that the problem of adaptive growth in structured changing environments, such as the gut, can be viewed as probabilistic inference. We analyze environments that are "meta-changing": where there are changes in the way the environment fluctuates, governed by a mechanism unobservable to cells. We develop a dynamic Bayesian model of these environments and show that a real-time inference algorithm (particle filtering) for this model can be used as a microbial growth strategy implementable in molecular circuits. The growth strategy suggested by our model outperforms heuristic strategies, and points to a class of algorithms that could support real-time probabilistic inference in natural or synthetic cellular circuits.
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Affiliation(s)
- Yarden Katz
- Department of Systems Biology, Harvard Medical School, Boston, MA, United States; Berkman Klein Center for Internet & Society, Harvard University, Cambridge, MA, United States
| | - Michael Springer
- Department of Systems Biology, Harvard Medical School , Boston , MA , United States
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42
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Snowdon C, Johnston M. A novel role for yeast casein kinases in glucose sensing and signaling. Mol Biol Cell 2016; 27:3369-3375. [PMID: 27630263 PMCID: PMC5170868 DOI: 10.1091/mbc.e16-05-0342] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 09/06/2016] [Indexed: 01/05/2023] Open
Abstract
The yeast casein kinases function upstream of the glucose sensors in the sensor/receptor-repressor signaling pathway. The sensor Rgt2 undergoes Yck-dependent phosphorylation on its C-terminal tail, which is necessary for Mth1 and Std1 binding and downstream signaling. Yeasts have sophisticated signaling pathways for sensing glucose, their preferred carbon source, to regulate its uptake and metabolism. One of these is the sensor/receptor-repressor (SRR) pathway, which detects extracellular glucose and transmits an intracellular signal that induces expression of HXT genes. The yeast casein kinases (Ycks) are key players in this pathway. Our model of the SRR pathway had the Ycks functioning downstream of the glucose sensors, transmitting the signal from the sensors to the Mth1 and Std1 corepressors that are required for repression of HXT gene expression. However, we found that overexpression of Yck1 fails to restore glucose signaling in a glucose sensor mutant. Conversely, overexpression of a glucose sensor suppresses the signaling defect of a yck mutant. These results suggest that the Ycks act upstream or at the level of the glucose sensors. Indeed, we found that the glucose sensor Rgt2 is phosphorylated on Yck consensus sites in its C-terminal tail in a Yck-dependent manner and that this phosphorylation is required for corepressor binding and ultimately HXT expression. This leads to a revised model of the SRR pathway in which the Ycks prime a site on the cytoplasmic tails of the glucose sensors to promote binding of the corepressors.
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Affiliation(s)
- Chris Snowdon
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045
| | - Mark Johnston
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045
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43
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Rani M, Raj S, Dayaman V, Kumar M, Dua M, Johri AK. Functional Characterization of a Hexose Transporter from Root Endophyte Piriformospora indica. Front Microbiol 2016; 7:1083. [PMID: 27499747 PMCID: PMC4957513 DOI: 10.3389/fmicb.2016.01083] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 06/28/2016] [Indexed: 11/30/2022] Open
Abstract
Understanding the mechanism of photosynthate transfer at symbiotic interface by fungal monosaccharide transporter is of substantial importance. The carbohydrate uptake at the apoplast by the fungus is facilitated by PiHXT5 hexose transporter in root endophytic fungus Piriformospora indica. The putative PiHXT5 belongs to MFS superfamily with 12 predicted transmembrane helices. It possess sugar transporter PFAM motif (PF0083) and MFS superfamily domain (PS50850). It contains the signature tags related to glucose transporter GLUT1 of human erythrocyte. PiHXT5 is regulated in response to mutualism as well as glucose concentration. We have functionally characterized PiHXT5 by complementation of hxt-null mutant of Saccharomyces cerevisiae EBY.VW4000. It is involved in transport of multiple sugars ranging from D-glucose, D-fructose, D-xylose, D-mannose, D-galactose with decreasing affinity. The uncoupling experiments indicate that it functions as H(+)/glucose co-transporter. Further, pH dependence analysis suggests that it functions maximum between pH 5 and 6. The expression of PiHXT5 is dependent on glucose concentration and was found to be expressed at low glucose levels (1 mM) which indicate its role as a high affinity glucose transporter. Our study on this sugar transporter will help in better understanding of carbon metabolism and flow in this agro-friendly fungus.
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Affiliation(s)
- Mamta Rani
- School of Life Sciences, Jawaharlal Nehru UniversityNew Delhi, India
| | - Sumit Raj
- School of Life Sciences, Jawaharlal Nehru UniversityNew Delhi, India
| | - Vikram Dayaman
- School of Life Sciences, Jawaharlal Nehru UniversityNew Delhi, India
| | - Manoj Kumar
- School of Life Sciences, Jawaharlal Nehru UniversityNew Delhi, India
| | - Meenakshi Dua
- School of Environmental Sciences, Jawaharlal Nehru UniversityNew Delhi, India
| | - Atul K. Johri
- School of Life Sciences, Jawaharlal Nehru UniversityNew Delhi, India
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44
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Ryu S, Hipp J, Trinh CT. Activating and Elucidating Metabolism of Complex Sugars in Yarrowia lipolytica. Appl Environ Microbiol 2016; 82:1334-1345. [PMID: 26682853 PMCID: PMC4751822 DOI: 10.1128/aem.03582-15] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 12/14/2015] [Indexed: 11/20/2022] Open
Abstract
The oleaginous yeast Yarrowia lipolytica is an industrially important host for production of organic acids, oleochemicals, lipids, and proteins with broad biotechnological applications. Albeit known for decades, the unique native metabolism of Y. lipolytica for using complex fermentable sugars, which are abundant in lignocellulosic biomass, is poorly understood. In this study, we activated and elucidated the native sugar metabolism in Y. lipolytica for cell growth on xylose and cellobiose as well as their mixtures with glucose through comprehensive metabolic and transcriptomic analyses. We identified 7 putative glucose-specific transporters, 16 putative xylose-specific transporters, and 4 putative cellobiose-specific transporters that are transcriptionally upregulated for growth on respective single sugars. Y. lipolytica is capable of using xylose as a carbon source, but xylose dehydrogenase is the key bottleneck of xylose assimilation and is transcriptionally repressed by glucose. Y. lipolytica has a set of 5 extracellular and 6 intracellular β-glucosidases and is capable of assimilating cellobiose via extra- and intracellular mechanisms, the latter being dominant for growth on cellobiose as a sole carbon source. Strikingly, Y. lipolytica exhibited enhanced sugar utilization for growth in mixed sugars, with strong carbon catabolite activation for growth on the mixture of xylose and cellobiose and with mild carbon catabolite repression of glucose on xylose and cellobiose. The results of this study shed light on fundamental understanding of the complex native sugar metabolism of Y. lipolytica and will help guide inverse metabolic engineering of Y. lipolytica for enhanced conversion of biomass-derived fermentable sugars to chemicals and fuels.
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Affiliation(s)
- Seunghyun Ryu
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee, USA
| | - Julie Hipp
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee, USA
| | - Cong T Trinh
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee, USA
- Bredesen Center for Interdisciplinary Research and Graduate Education, University of Tennessee, Knoxville, Tennessee, USA
- University of Tennessee, Knoxville, Tennessee, USA; Bioenergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
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45
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Roy A, Hashmi S, Li Z, Dement AD, Cho KH, Kim JH. The glucose metabolite methylglyoxal inhibits expression of the glucose transporter genes by inactivating the cell surface glucose sensors Rgt2 and Snf3 in yeast. Mol Biol Cell 2016; 27:862-71. [PMID: 26764094 PMCID: PMC4803311 DOI: 10.1091/mbc.e15-11-0789] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 01/05/2016] [Indexed: 01/04/2023] Open
Abstract
Methylglyoxal (MG) is a cytotoxic by-product of glycolysis. MG inhibits the growth of glucose-fermenting yeast cells by inhibiting glycolysis. MG does so by inducing endocytosis and degradation of the cell-surface glucose sensors Rgt2 and Snf3, which are required for glucose induction of HXT (glucose transporter) gene expression. Methylglyoxal (MG) is a cytotoxic by-product of glycolysis. MG has inhibitory effect on the growth of cells ranging from microorganisms to higher eukaryotes, but its molecular targets are largely unknown. The yeast cell-surface glucose sensors Rgt2 and Snf3 function as glucose receptors that sense extracellular glucose and generate a signal for induction of expression of genes encoding glucose transporters (HXTs). Here we provide evidence that these glucose sensors are primary targets of MG in yeast. MG inhibits the growth of glucose-fermenting yeast cells by inducing endocytosis and degradation of the glucose sensors. However, the glucose sensors with mutations at their putative ubiquitin-acceptor lysine residues are resistant to MG-induced degradation. These results suggest that the glucose sensors are inactivated through ubiquitin-mediated endocytosis and degraded in the presence of MG. In addition, the inhibitory effect of MG on the glucose sensors is greatly enhanced in cells lacking Glo1, a key component of the MG detoxification system. Thus the stability of these glucose sensors seems to be critically regulated by intracellular MG levels. Taken together, these findings suggest that MG attenuates glycolysis by promoting degradation of the cell-surface glucose sensors and thus identify MG as a potential glycolytic inhibitor.
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Affiliation(s)
- Adhiraj Roy
- Department of Biochemistry and Molecular Medicine, George Washington University School of Medicine and Health Science, Washington, DC 20037
| | - Salman Hashmi
- Department of Biochemistry and Molecular Medicine, George Washington University School of Medicine and Health Science, Washington, DC 20037
| | - Zerui Li
- Department of Biochemistry and Molecular Medicine, George Washington University School of Medicine and Health Science, Washington, DC 20037
| | - Angela D Dement
- Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
| | - Kyu Hong Cho
- Department of Biology, Indiana State University, Terre Haute, IN 47809
| | - Jeong-Ho Kim
- Department of Biochemistry and Molecular Medicine, George Washington University School of Medicine and Health Science, Washington, DC 20037
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46
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Unden G, Wörner S, Monzel C. Cooperation of Secondary Transporters and Sensor Kinases in Transmembrane Signalling: The DctA/DcuS and DcuB/DcuS Sensor Complexes of Escherichia coli. Adv Microb Physiol 2016; 68:139-67. [PMID: 27134023 DOI: 10.1016/bs.ampbs.2016.02.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Many membrane-bound sensor kinases require accessory proteins for function. The review describes functional control of membrane-bound sensors by transporters. The C4-dicarboxylate sensor kinase DcuS requires the aerobic or anaerobic C4-dicarboxylate transporters DctA or DcuB, respectively, for function and forms DctA/DcuS or DcuB/DcuS sensor complexes. Free DcuS is in the permanent (ligand independent) ON state. The DctA/DcuS and DcuB/DcuS complexes, on the other hand, control expression in response to C4-dicarboxylates. In DctA/DcuS, helix 8b of DctA and the PASC domain of DcuS are involved in interaction. The stimulus is perceived by the extracytoplasmic sensor domain (PASP) of DcuS. The signal is transmitted across the membrane by a piston-type movement of TM2 of DcuS which appears to be pulled (by analogy to the homologous citrate sensor CitA) by compaction of PASP after C4-dicarboxylate binding. In the cytoplasm, the signal is perceived by the PASC domain of DcuS. PASC inhibits together with DctA the kinase domain of DcuS which is released after C4-dicarboxylate binding. DcuS exhibits two modes for regulating expression of target genes. At higher C4-dicarboxylate levels, DcuS is part of the DctA/DcuS complex and in the C4-dicarboxylate-responsive form which stimulates expression of target genes in response to the concentration of the C4-dicarboxylates (catabolic use of C4-dicarboxylates, mode I regulation). At limiting C4-dicarboxylate concentrations (≤0.05mM), expression of DctA drops and free DcuS appears. Free DcuS is in the permanent ON state (mode II regulation) and stimulates low level (C4-dicarboxylate independent) DctA synthesis for DctA/DcuS complex formation and anabolic C4-dicarboxylate uptake.
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Affiliation(s)
- G Unden
- Institute for Microbiology and Wine Research, University of Mainz, Mainz, Germany.
| | - S Wörner
- Institute for Microbiology and Wine Research, University of Mainz, Mainz, Germany
| | - C Monzel
- Institute for Microbiology and Wine Research, University of Mainz, Mainz, Germany
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47
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Vicedo E, Gasik Z, Dong YA, Goldberg T, Rost B. Protein disorder reduced in Saccharomyces cerevisiae to survive heat shock. F1000Res 2015; 4:1222. [PMID: 26673203 PMCID: PMC4670006 DOI: 10.12688/f1000research.7178.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/02/2015] [Indexed: 11/20/2022] Open
Abstract
Recent experiments established that a culture of
Saccharomyces cerevisiae (baker’s yeast) survives sudden high temperatures by specifically duplicating the entire chromosome III and two chromosomal fragments (from IV and XII). Heat shock proteins (HSPs) are not significantly over-abundant in the duplication. In contrast, we suggest a simple algorithm to “
postdict” the experimental results: Find a small enough chromosome with minimal protein disorder and duplicate this region. This algorithm largely explains all observed duplications. In particular, all regions duplicated in the experiment reduced the overall content of protein disorder. The differential analysis of the functional makeup of the duplication remained inconclusive. Gene Ontology (GO) enrichment suggested over-representation in processes related to reproduction and nutrient uptake. Analyzing the protein-protein interaction network (PPI) revealed that few network-central proteins were duplicated. The predictive hypothesis hinges upon the concept of reducing proteins with long regions of disorder in order to become less sensitive to heat shock attack.
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Affiliation(s)
- Esmeralda Vicedo
- Department of Informatics, Bioinformatics & Computational Biology, TUM, Munich, Germany ; Institute of Experimental Physics, Division of Biophysics, University of Warsaw, Warsaw, Poland
| | - Zofia Gasik
- Department of Informatics, Bioinformatics & Computational Biology, TUM, Munich, Germany ; Graduate School of Information Science in Health, TUM, Munich, Germany
| | - Yu-An Dong
- Department of Informatics, Bioinformatics & Computational Biology, TUM, Munich, Germany ; Institute of Systems Biology, Shanghai University, Shanghai, China
| | - Tatyana Goldberg
- Department of Informatics, Bioinformatics & Computational Biology, TUM, Munich, Germany
| | - Burkhard Rost
- Department of Informatics, Bioinformatics & Computational Biology, TUM, Munich, Germany ; Institute of Advanced Study, TUM, Munich, Germany ; Institute for Food and Plant Sciences WZW, TUM, Freising, Germany
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48
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Ng TS, Chew SY, Rangasamy P, Mohd Desa MN, Sandai D, Chong PP, Than LTL. SNF3 as High Affinity Glucose Sensor and Its Function in Supporting the Viability of Candida glabrata under Glucose-Limited Environment. Front Microbiol 2015; 6:1334. [PMID: 26648919 PMCID: PMC4664639 DOI: 10.3389/fmicb.2015.01334] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 11/16/2015] [Indexed: 01/09/2023] Open
Abstract
Candida glabrata is an emerging human fungal pathogen that has efficacious nutrient sensing and responsiveness ability. It can be seen through its ability to thrive in diverse range of nutrient limited-human anatomical sites. Therefore, nutrient sensing particularly glucose sensing is thought to be crucial in contributing to the development and fitness of the pathogen. This study aimed to elucidate the role of SNF3 (Sucrose Non Fermenting 3) as a glucose sensor and its possible role in contributing to the fitness and survivability of C. glabrata in glucose-limited environment. The SNF3 knockout strain was constructed and subjected to different glucose concentrations to evaluate its growth, biofilm formation, amphotericin B susceptibility, ex vivo survivability and effects on the transcriptional profiling of the sugar receptor repressor (SRR) pathway-related genes. The CgSNF3Δ strain showed a retarded growth in low glucose environments (0.01 and 0.1%) in both fermentation and respiration-preferred conditions but grew well in high glucose concentration environments (1 and 2%). It was also found to be more susceptible to amphotericin B in low glucose environment (0.1%) and macrophage engulfment but showed no difference in the biofilm formation capability. The deletion of SNF3 also resulted in the down-regulation of about half of hexose transporters genes (four out of nine). Overall, the deletion of SNF3 causes significant reduction in the ability of C. glabrata to sense limited surrounding glucose and consequently disrupts its competency to transport and perform the uptake of this critical nutrient. This study highlighted the role of SNF3 as a high affinity glucose sensor and its role in aiding the survivability of C. glabrata particularly in glucose limited environment.
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Affiliation(s)
- Tzu Shan Ng
- Department of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, Universiti Putra MalaysiaSerdang, Malaysia
| | - Shu Yih Chew
- Department of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, Universiti Putra MalaysiaSerdang, Malaysia
| | - Premmala Rangasamy
- Department of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, Universiti Putra MalaysiaSerdang, Malaysia
| | - Mohd N. Mohd Desa
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra MalaysiaSerdang, Malaysia
| | - Doblin Sandai
- Infectomics Cluster, Advanced Medical and Dental Institute, Universiti Sains MalaysiaBertam, Malaysia
| | - Pei Pei Chong
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra MalaysiaSerdang, Malaysia
| | - Leslie Thian Lung Than
- Department of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, Universiti Putra MalaysiaSerdang, Malaysia
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Ng TS, Mohd Desa MN, Sandai D, Chong PP, Than LTL. Phylogenetic and Transcripts Profiling of Glucose Sensing Related Genes in Candida glabrata. Jundishapur J Microbiol 2015; 8:e25177. [PMID: 26855740 PMCID: PMC4735840 DOI: 10.5812/jjm.25177] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Revised: 07/17/2015] [Accepted: 07/22/2015] [Indexed: 01/02/2023] Open
Abstract
Background: The sensing mechanism of glucose in Saccharomyces cerevisiae is well studied. However, such information is scarcely found in other yeast species such as Candida glabrata. Objectives: This study aimed to identify the glucose sensing pathway related genes of C. glabrata and to analyze the regulation pattern of these genes in response to different surrounding glucose concentrations through the quantitative real time polymerase chain reaction (qRT-PCR). Materials and Methods: Phylogenetic analysis was carried out on predicted amino acid sequences of C. glabrata and S. cerevisiae to compare their degree of similarity. In addition, the growth of C. glabrata in response to different amounts of glucose (0%, 0.01%, 0.1%, 1% and 2%) was evaluated via the spot dilution assay on prepared agar medium. Besides, the SNF3 and RGT2, which act as putative glucose sensors, and the RGT1 and MIG1, which act as putative transcriptional regulators and selected downstream hexose transporters (HXTs), were analysed through qRT-PCR analysis for the gene expression level under different glucose concentrations. Results: Comparative analysis of predicted amino acids in the phylogenetic tree showed high similarity between C. glabrata and S cerevisiae. Besides, C. glabrata demonstrated the capability to grow in glucose levels as low as 0.01% in the spot dilution assay. In qRT-PCR analysis, differential expressions were observed in selected genes when C. glabrata was subjected to different glucose concentrations. Conclusions: The constructed phylogenetic tree suggests the close evolutionary relationship between C. glabrata and S. cerevisiae. The capability of C. glabrata to grow in extremely low glucose environments and the differential expression of selected glucose-sensing related genes suggested the possible role of these genes in modulating the growth of C. glabrata in response to different glucose concentrations. This study helps deepen our understanding of the glucose sensing mechanism in C. glabrata and serves to provide fundamental data that may assist in unveiling this mechanism as a potential drug target.
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Affiliation(s)
- Tzu Shan Ng
- Department of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
| | - Mohd Nasir Mohd Desa
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
| | - Doblin Sandai
- Advanced Medical and Dental Institute, Universiti Sains Malaysia, 13200 Kepala Batas, Penang, Malaysia
| | - Pei Pei Chong
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
| | - Leslie Thian Lung Than
- Department of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
- Corresponding author: Leslie Thian Lung Than, Department of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia. Tel: +60-389472373, Fax: +60-389413802, E-mail:
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50
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Zanon L, Falchi R, Hackel A, Kühn C, Vizzotto G. Expression of peach sucrose transporters in heterologous systems points out their different physiological role. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2015; 238:262-72. [PMID: 26259193 DOI: 10.1016/j.plantsci.2015.06.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 06/10/2015] [Accepted: 06/14/2015] [Indexed: 05/26/2023]
Abstract
Sucrose is the major phloem-translocated component in a number of economically important plant species. The comprehension of the mechanisms involved in sucrose transport in peach fruit appears particularly relevant, since the accumulation of this sugar, during ripening, is crucial for the growth and quality of the fruit. Here, we report the functional characterisation and subcellular localisation of three sucrose transporters (PpSUT1, PpSUT2, PpSUT4) in peach, and we formulate novel hypotheses about their role in accumulation of sugar. We provide evidence, about the capability of both PpSUT1 and PpSUT4, expressed in mutant yeast strains to transport sucrose. The functionality of PpSUT1 at the plasma membrane, and of PpSUT4 at the tonoplast, has been demonstrated. On the other hand, the functionality of PpSUT2 was not confirmed: this protein is unable to complement two sucrose uptake-deficient mutant yeast strains. Our results corroborate the hypotheses that PpSUT1 partakes in phloem loading in leaves, and PpSUT4 sustains cell metabolism by regulating sucrose efflux from the vacuole.
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Affiliation(s)
- Laura Zanon
- Dipartimento di Scienze Agrarie e Ambientali, University of Udine, via delle Scienze 206, 33100 Udine, Italy.
| | - Rachele Falchi
- Dipartimento di Scienze Agrarie e Ambientali, University of Udine, via delle Scienze 206, 33100 Udine, Italy.
| | - Aleksandra Hackel
- Department of Plant Physiology, Humboldt University of Berlin, Philippstr. 13, Building 12, 10115 Berlin, Germany.
| | - Christina Kühn
- Department of Plant Physiology, Humboldt University of Berlin, Philippstr. 13, Building 12, 10115 Berlin, Germany.
| | - Giannina Vizzotto
- Dipartimento di Scienze Agrarie e Ambientali, University of Udine, via delle Scienze 206, 33100 Udine, Italy.
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