scholarly journals Characterization of the Candida albicans Amino Acid Permease Family: Gap2 Is the Only General Amino Acid Permease and Gap4 Is an S-Adenosylmethionine (SAM) Transporter Required for SAM-Induced Morphogenesis

mSphere ◽  
2016 ◽  
Vol 1 (6) ◽  
Author(s):  
Lucie Kraidlova ◽  
Sanne Schrevens ◽  
Hélène Tournu ◽  
Griet Van Zeebroeck ◽  
Hana Sychrova ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Candida Albicans ◽  
Amino Acid ◽  
Virulence Factor ◽  
Amino Acid Transporters ◽  
Amino Acid Permease ◽  
Content Type ◽  
Important Virulence Factor ◽  
General Amino Acid Permease

ABSTRACT Candida albicans is a commensal organism that can thrive in many niches in its human host. The environmental conditions at these different niches differ quite a bit, and this fungus must be able to sense these changes and adapt its metabolism to them. Apart from glucose and other sugars, the uptake of amino acids is very important. This is underscored by the fact that the C. albicans genome encodes 6 orthologues of the Saccharomyces. cerevisiae general amino acid permease Gap1 and many other amino acid transporters. In this work, we characterize these six permeases and we show that C. albicans Gap2 is the functional orthologue of ScGap1 and that C. albicans Gap4 is an orthologue of ScSam3, an S-adenosylmethionine (SAM) transporter. Furthermore, we show that Gap4 is required for SAM-induced morphogenesis, an important virulence factor of C. albicans. Amino acids are key sources of nitrogen for growth of Candida albicans. In order to detect and take up these amino acids from a broad range of different and changing nitrogen sources inside the host, this fungus must be able to adapt via its expression of genes for amino acid uptake and further metabolism. We analyzed six C. albicans putative general amino acid permeases based on their homology to the Saccharomyces cerevisiae Gap1 general amino acid permease. We generated single- and multiple-deletion strains and found that, based on growth assays and transcriptional or posttranscriptional regulation, Gap2 is the functional orthologue to ScGap1, with broad substrate specificity. Expression analysis showed that expression of all GAP genes is under control of the Csy1 amino acid sensor, which is different from the situation in S. cerevisiae, where the expression of ScGAP1 is not regulated by Ssy1. We show that Gap4 is the functional orthologue of ScSam3, the only S-adenosylmethionine (SAM) transporter in S. cerevisiae, and we report that Gap4 is required for SAM-induced morphogenesis. IMPORTANCE Candida albicans is a commensal organism that can thrive in many niches in its human host. The environmental conditions at these different niches differ quite a bit, and this fungus must be able to sense these changes and adapt its metabolism to them. Apart from glucose and other sugars, the uptake of amino acids is very important. This is underscored by the fact that the C. albicans genome encodes 6 orthologues of the Saccharomyces. cerevisiae general amino acid permease Gap1 and many other amino acid transporters. In this work, we characterize these six permeases and we show that C. albicans Gap2 is the functional orthologue of ScGap1 and that C. albicans Gap4 is an orthologue of ScSam3, an S-adenosylmethionine (SAM) transporter. Furthermore, we show that Gap4 is required for SAM-induced morphogenesis, an important virulence factor of C. albicans.

scholarly journals Rhizobium leguminosarum Has a Second General Amino Acid Permease with Unusually Broad Substrate Specificity and High Similarity to Branched-Chain Amino Acid Transporters (Bra/LIV) of the ABC Family

2002 ◽  
Vol 184 (15) ◽  
pp. 4071-4080 ◽  
Author(s):  
A. H. F. Hosie ◽  
D. Allaway ◽  
C. S. Galloway ◽  
H. A. Dunsby ◽  
P. S. Poole
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Rhizobium Leguminosarum ◽  
Binding Protein ◽  
Amino Acid Transporters ◽  
Acid Uptake ◽  
Amino Acid Permease ◽  
Branched Chain Amino Acid ◽  
General Amino Acid Permease ◽  
Branched Chain

ABSTRACT Amino acid uptake by Rhizobium leguminosarum is dominated by two ABC transporters, the general amino acid permease (Aap) and the branched-chain amino acid permease (BraRl). Characterization of the solute specificity of BraRl shows it to be the second general amino acid permease of R. leguminosarum. Although BraRl has high sequence identity to members of the family of hydrophobic amino acid transporters (HAAT), it transports a broad range of solutes, including acidic and basic polar amino acids (l-glutamate, l-arginine, and l-histidine), in addition to neutral amino acids (l-alanine and l-leucine). While amino and carboxyl groups are required for transport, solutes do not have to be α-amino acids. Consistent with this, BraRl is the first ABC transporter to be shown to transport γ-aminobutyric acid (GABA). All previously identified bacterial GABA transporters are secondary carriers of the amino acid-polyamine-organocation (APC) superfamily. Also, transport by BraRl does not appear to be stereospecific as d amino acids cause significant inhibition of uptake of l-glutamate and l-leucine. Unlike all other solutes tested, l-alanine uptake is not dependent on solute binding protein BraCRl. Therefore, a second, unidentified solute binding protein may interact with the BraDEFGRl membrane complex during l-alanine uptake. Overall, the data indicate that BraRl is a general amino acid permease of the HAAT family. Furthermore, BraRl has the broadest solute specificity of any characterized bacterial amino acid transporter.

N-Acetylglucosamine-inducible CaGAP1 encodes a general amino acid permease which co-ordinates external nitrogen source response and morphogenesis in Candida albicans

Microbiology ◽  
2003 ◽  
Vol 149 (9) ◽  
pp. 2597-2608 ◽  
Author(s):  
Subhrajit Biswas ◽  
Monideepa Roy ◽  
Asis Datta
Keyword(s):  
Amino Acids ◽  
Candida Albicans ◽  
Amino Acid ◽  
Genomic Library ◽  
Northern Analysis ◽  
Dependent Manner ◽  
Amino Acid Permease ◽  
Environmental Signals ◽  
General Amino Acid Permease ◽  
Hyphal Formation

Candida albicans is able to grow in a variety of reversible morphological forms (yeast, pseudohyphal and hyphal) in response to various environmental signals, noteworthy among them being N-acetylglucosamine (GlcNAc). The gene CaGAP1, homologous to GAP1, which encodes the general amino acid permease from Saccharomyces cerevisiae, was isolated on the basis of its induction by GlcNAc through differential screening of a C. albicans genomic library. The gene could functionally complement an S. cerevisiae gap1 mutant by rendering it susceptible to the toxic amino acid analogue mimosine in minimal proline media. As in S. cerevisiae, mutation of the CaGAP1 gene had an effect on citrulline uptake in C. albicans. Northern analysis showed that GlcNAc-induced expression of CaGAP1 was further enhanced in synthetic minimal media supplemented with single amino acids (glutamate, proline and glutamine) or urea (without amino acids) but repressed in minimal ammonium media. Induction of CaGAP1 expression by GlcNAc was nullified in C. albicans deleted for the transcription factor CPH1 and the hyphal regulator RAS1, indicating the involvement of Cph1p-dependent Ras1p signalling in CaGAP1 expression. A homozygous mutant of this gene showed defective hyphal formation in solid hyphal-inducing media and exhibited less hyphal clumps when induced by GlcNAc. Alteration of morphology and short filamentation under nitrogen-starvation conditions in the heterozygous mutant suggested that CaGAP1 affects morphogenesis in a dose-dependent manner.

scholarly journals Different Ubiquitin Signals Act at the Golgi and Plasma Membrane to Direct GAP1 Trafficking

2008 ◽  
Vol 19 (7) ◽  
pp. 2962-2972 ◽  
Author(s):  
April L. Risinger ◽  
Chris A. Kaiser
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Plasma Membrane ◽  
Amino Acid ◽  
Protein Sorting ◽  
High Capacity ◽  
Amino Acid Permease ◽  
Acid Addition ◽  
Amino Acid Levels ◽  
General Amino Acid Permease

The high capacity general amino acid permease, Gap1p, in Saccharomyces cerevisiae is distributed between the plasma membrane and internal compartments according to availability of amino acids. When internal amino acid levels are low, Gap1p is localized to the plasma membrane where it imports available amino acids from the medium. When sufficient amino acids are imported, Gap1p at the plasma membrane is endocytosed and newly synthesized Gap1p is delivered to the vacuole; both sorting steps require Gap1p ubiquitination. Although it has been suggested that identical trans-acting factors and Gap1p ubiquitin acceptor sites are involved in both processes, we define unique requirements for each of the ubiquitin-mediated sorting steps involved in delivery of Gap1p to the vacuole upon amino acid addition. Our finding that distinct ubiquitin-mediated sorting steps employ unique trans-acting factors, ubiquitination sites on Gap1p, and types of ubiquitination demonstrates a previously unrecognized level of specificity in ubiquitin-mediated protein sorting.

scholarly journals Changes in membrane proteins associated with inhibition of the general amino acid permease of yeast (Saccharomyces cerevisiae)

1981 ◽  
Vol 196 (2) ◽  
pp. 531-536 ◽  
Author(s):  
J R Woodward ◽  
H L Kornberg
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Amino Acid ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Wild Type ◽  
Amino Acid Permease ◽  
Yeast Saccharomyces Cerevisiae ◽  
General Amino Acid Permease ◽  
Wild Type Yeast

The general amino acid permease (‘Gap’) system of the wild-type yeast (Saccharomyces cerevisiae) strain Y185 is inhibited by the uptake and accumulation of its substrate amino acids. Surprisingly, this inhibition persists even after ‘pools’ of amino acids, accumulated initially, have returned to normal sizes. Recovery from this inhibition depends on a supply of energy and involves the synthesis of a membrane protein component of the Gap system.

scholarly journals Regulation of Amino Acid Transport in Saccharomyces cerevisiae

2019 ◽  
Vol 83 (4) ◽  
Author(s):  
Frans Bianchi ◽  
Joury S. van’t Klooster ◽  
Stephanie J. Ruiz ◽  
Bert Poolman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Amino Acid ◽  
De Novo ◽  
Amino Acid Transporters ◽  
Content Type ◽  
Growth And Survival ◽  
Amino Acid Homeostasis ◽  
Underlying Mechanisms ◽  
Amino Acid Sensing

SUMMARY We review the mechanisms responsible for amino acid homeostasis in Saccharomyces cerevisiae and other fungi. Amino acid homeostasis is essential for cell growth and survival. Hence, the de novo synthesis reactions, metabolic conversions, and transport of amino acids are tightly regulated. Regulation varies from nitrogen pool sensing to control by individual amino acids and takes place at the gene (transcription), protein (posttranslational modification and allostery), and vesicle (trafficking and endocytosis) levels. The pools of amino acids are controlled via import, export, and compartmentalization. In yeast, the majority of the amino acid transporters belong to the APC (amino acid-polyamine-organocation) superfamily, and the proteins couple the uphill transport of amino acids to the electrochemical proton gradient. Although high-resolution structures of yeast amino acid transporters are not available, homology models have been successfully exploited to determine and engineer the catalytic and regulatory functions of the proteins. This has led to a further understanding of the underlying mechanisms of amino acid sensing and subsequent downregulation of transport. Advances in optical microscopy have revealed a new level of regulation of yeast amino acid transporters, which involves membrane domain partitioning. The significance and the interrelationships of the latest discoveries on amino acid homeostasis are put in context.

scholarly journals Growth Inhibition by Amino Acids in Saccharomyces cerevisiae

2020 ◽  
Vol 9 (1) ◽  
pp. 7
Author(s):  
Stephanie J. Ruiz ◽  
Joury S. van ’t Klooster ◽  
Frans Bianchi ◽  
Bert Poolman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Amino Acid ◽  
Growth Defect ◽  
Amino Acid Transporters ◽  
Amino Acid Permease ◽  
Cytosolic Ph ◽  
Acid Sensitivity ◽  
Growth Inhibitory

Amino acids are essential metabolites but can also be toxic when present at high levels intracellularly. Substrate-induced downregulation of amino acid transporters in Saccharomyces cerevisiae is thought to be a mechanism to avoid this toxicity. It has been shown that unregulated uptake by the general amino acid permease Gap1 causes cells to become sensitive to amino acids. Here, we show that overexpression of eight other amino acid transporters (Agp1, Bap2, Can1, Dip5, Gnp1, Lyp1, Put4, or Tat2) also induces a growth defect when specific single amino acids are present at concentrations of 0.5–5 mM. We can now state that all proteinogenic amino acids, as well as the important metabolite ornithine, are growth inhibitory to S. cerevisiae when transported into the cell at high enough levels. Measurements of initial transport rates and cytosolic pH show that toxicity is due to amino acid accumulation and not to the influx of co-transported protons. The amino acid sensitivity phenotype is a useful tool that reports on the in vivo activity of transporters and has allowed us to identify new transporter-specific substrates.

scholarly journals The Candida albicans GAP Gene Family Encodes Permeases Involved in General and Specific Amino Acid Uptake and Sensing

2011 ◽  
Vol 10 (9) ◽  
pp. 1219-1229 ◽  
Author(s):  
Lucie Kraidlova ◽  
Griet Van Zeebroeck ◽  
Patrick Van Dijck ◽  
Hana Sychrová
Keyword(s):  
Amino Acids ◽  
Candida Albicans ◽  
Amino Acid ◽  
Fungal Pathogens ◽  
Signal Transduction Pathway ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Amino Acid Permease ◽  
Content Type ◽  
Six Genes

ABSTRACTTheSaccharomyces cerevisiaegeneral amino acid permease Gap1 (ScGap1) not only mediates the uptake of most amino acids but also functions as a receptor for the activation of protein kinase A (PKA). Fungal pathogens can colonize different niches in the host, each containing various levels of different amino acids and sugars. TheCandida albicansgenome contains six genes homologous to theS. cerevisiae GAP1. The expression of these six genes inS. cerevisiaeshowed that the products of all sixC. albicansgenes differ in their transport capacities.C. albicansGap2 (CaGap2) is the true orthologue ofScGap1 as it transports all tested amino acids. The otherCaGap proteins have narrower substrate specificities thoughCaGap1 andCaGap6 transport several structurally unrelated amino acids.CaGap1,CaGap2, andCaGap6 also function as sensors. Upon detecting some amino acids, e.g., methionine, they are involved in a rapid activation of trehalase, a downstream target of PKA. Our data show thatCaGAPgenes can be functionally expressed inS. cerevisiaeand thatCaGap permeases communicate to the intracellular signal transduction pathway similarly toScGap1.

scholarly journals MCH4is a multicopy suppressor of glycine toxicity inSaccharomyces cerevisiae

2019 ◽  
Author(s):  
Artem V. Melnykov ◽  
Elliot L. Elson
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Amino Acid ◽  
Osmotic Shock ◽  
Inhibitory Effects ◽  
Amino Acid Permease ◽  
Multicopy Suppressor ◽  
Low Concentrations ◽  
General Amino Acid Permease ◽  
Acid Toxicity

AbstractSaccharomyces cerevisiaecan either import amino acids from the surrounding or synthesize inside the cell, and both processes are tightly regulated. Disruption of such regulation can result in amino acid toxicity to the cell through mechanisms that are poorly understood. In this study we make use of a mutant strain with deregulated general amino acid permease gene whose growth is inhibited by low concentrations of several amino acids. We carry out multicopy suppression screen with several toxic amino acids and identifyMCH4as a gene that suppresses inhibitory effects of glycine. We find that expression ofMCH4is regulated by osmotic shock but not other kinds of stress. These findings are discussed in the context of possible mechanisms of amino acid toxicity.

scholarly journals Growth inhibition by amino acids inSaccharomyces cerevisiae

2017 ◽  
Author(s):  
Stephanie J. Ruiz ◽  
Joury S. van ’t Klooster ◽  
Frans Bianchi ◽  
Bert Poolman
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Growth Defect ◽  
Amino Acid Transporters ◽  
Amino Acid Permease ◽  
Cytosolic Ph ◽  
Acid Sensitivity ◽  
Growth Inhibitory ◽  
General Amino Acid Permease

AbstractAmino acids are essential metabolites but can also be toxic when present at high levels intracellularly. Substrate-induced down-regulation of amino acid transporters inSaccharomyces cerevisiaeis thought to be a mechanism to avoid this toxicity. It has been shown that unregulated uptake by the general amino acid permease Gap1 causes cells to become sensitive to amino acids. Here, we show that overexpression of eight other amino acid transporters (Agp1, Bap2, Can1, Dip5, Gnp1, Lyp1, Put4 or Tat2) also induces a growth defect when specific single amino acids are present at concentrations of 0.5–5 mM. We can now state that all proteinogenic amino acids, as well as the important metabolite ornithine, are growth inhibitory toS. cerevisiaewhen transported into the cell at high enough levels. Measurements of initial transport rates and cytosolic pH show that toxicity is due to amino acid accumulation and not to the influx of co-transported protons. The amino acid sensitivity phenotype is a useful tool that reports on thein vivoactivity of transporters and has allowed us to identify new transporter-specific substrates.

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