scholarly journals Isp7 Is a Novel Regulator of Amino Acid Uptake in the TOR Signaling Pathway

2013 ◽  
Vol 34 (5) ◽  
pp. 794-806 ◽  
Author(s):  
Dana Laor ◽  
Adiel Cohen ◽  
Metsada Pasmanik-Chor ◽  
Varda Oron-Karni ◽  
Martin Kupiec ◽  
...  
Keyword(s):  
Amino Acid ◽  
Transcript Level ◽  
Amino Acid Uptake ◽  
Cellular Growth ◽  
Acid Uptake ◽  
Tor Signaling ◽  
Amino Acid Permease ◽  
Content Type ◽  
The Family ◽  
Nitrogen Conditions

TOR proteins reside in two distinct complexes, TOR complexes 1 and 2 (TORC1 and TORC2), that are central for the regulation of cellular growth, proliferation, and survival. TOR is also the target for the immunosuppressive and anticancer drug rapamycin. InSchizosaccharomyces pombe, disruption of the TSC complex, mutations in which can lead to the tuberous sclerosis syndrome in humans, results in a rapamycin-sensitive phenotype under poor nitrogen conditions. We show here that the sensitivity to rapamycin is mediated via inhibition of TORC1 and suppressed by overexpression ofisp7+, a member of the family of 2-oxoglutarate-Fe(II)-dependent oxygenase genes. The transcript level ofisp7+is negatively regulated by TORC1 but positively regulated by TORC2. Yet we find extensive similarity between the transcriptome of cells disrupted forisp7+and cells mutated in the catalytic subunit of TORC1. Moreover, Isp7 regulates amino acid permease expression in a fashion similar to that of TORC1 and opposite that of TORC2. Overexpression ofisp7+induces TORC1-dependent phosphorylation of ribosomal protein Rps6 while inhibiting TORC2-dependent phosphorylation and activation of the AGC-like kinase Gad8. Taken together, our findings suggest a central role for Isp7 in amino acid homeostasis and the presence ofisp7+-dependent regulatory loops that affect both TORC1 and TORC2.

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.

Development of amino acid uptake activity in Neurospora

1976 ◽  
Vol 22 (2) ◽  
pp. 115-120 ◽  
Author(s):  
Robert M. Railey ◽  
John A. Kinsey
Keyword(s):  
Amino Acid ◽  
Specific Activity ◽  
Morphological Changes ◽  
Amino Acid Uptake ◽  
Logarithmic Phase ◽  
Acid Uptake ◽  
Amino Acid Permease ◽  
Uptake Activity ◽  
Two Peaks ◽  
Germination And Growth

During the germination and growth of Neurospora conidia, amino acid permease systems I (neutral) and II (general) increase in specific activity. System III (basic) decreases in specific activity with the onset of germination. System I shows two peaks of activity during the logarithmic phase of growth. One peak occurs at 6 h, the other at 12 h of growth. Both peaks are abolished in the mtr mutant. Both peaks have a Km for phenylalanine of 40 μM. The peaks of system I activity appear to correlate with morphological changes.

scholarly journals Components of a Ubiquitin Ligase Complex Specify Polyubiquitination and Intracellular Trafficking of the General Amino Acid Permease

2001 ◽  
Vol 153 (4) ◽  
pp. 649-662 ◽  
Author(s):  
Stephen B. Helliwell ◽  
Sascha Losko ◽  
Chris A. Kaiser
Keyword(s):  
Plasma Membrane ◽  
Amino Acid ◽  
Nitrogen Source ◽  
Ubiquitin Ligase ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Amino Acid Permease ◽  
Intracellular Targeting ◽  
Ubiquitin Ligase Complex ◽  
General Amino Acid Permease

Gap1p, the general amino acid permease of Saccharomyces cerevisiae, is regulated by intracellular sorting decisions that occur in either Golgi or endosomal compartments. Depending on nitrogen source, Gap1p is transported to the plasma membrane, where it functions for amino acid uptake, or to the vacuole, where it is degraded. We found that overexpression of Bul1p or Bul2p, two nonessential components of the Rsp5p E3–ubiquitin ligase complex, causes Gap1p to be sorted to the vacuole regardless of nitrogen source. The double mutant bul1Δ bul2Δ has the inverse phenotype, causing Gap1p to be delivered to the plasma membrane more efficiently than in wild-type cells. In addition, bul1Δ bul2Δ can reverse the effect of lst4Δ, a mutation that normally prevents Gap1p from reaching the plasma membrane. Evaluation of Gap1p ubiquitination revealed a prominent polyubiquitinated species that was greatly diminished in a bul1Δ bul2Δ mutant. Both a rsp5-1 mutant and a COOH-terminal truncation of Gap1p behave as bul1Δ bul2Δ, causing constitutive delivery of Gap1p to the plasma membrane and decreasing Gap1p polyubiquitination. These results indicate that Bul1p and Bul2p, together with Rsp5p, generate a polyubiquitin signal on Gap1p that specifies its intracellular targeting to the vacuole.

scholarly journals Candida albicans Csy1p Is a Nutrient Sensor Important for Activation of Amino Acid Uptake and Hyphal Morphogenesis

2004 ◽  
Vol 3 (1) ◽  
pp. 135-143 ◽  
Author(s):  
Elisa Brega ◽  
Rachel Zufferey ◽  
Choukri Ben Mamoun
Keyword(s):  
Candida Albicans ◽  
Amino Acid ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Amino Acid Permease ◽  
Specific Amino Acid ◽  
Primary Amino ◽  
Amino Acid Sensing ◽  
Amino Acid Sensor

ABSTRACT Candida albicans is an important human pathogen that displays a remarkable ability to detect changes in its environment and to respond appropriately by changing its cell morphology and physiology. Serum- and amino acid-based media are known to induce filamentous growth in this organism. However, the mechanism by which amino acids induce filamentation is not yet known. Here, we describe the identification and characterization of the primary amino acid sensor of C. albicans, Csy1. We show that Csy1p plays an important role in amino acid sensing and filamentation. Loss of Csy1p results in a lack of amino acid-mediated activation of amino acid transport and a lack of induction of transcription of specific amino acid permease genes. Furthermore, a csy1Δ/csy1Δ strain, lacking Csy1p, is defective in filamentation and displays altered colony morphology in serum- and amino acid-based media. These data provide the first evidence that C. albicans utilizes the amino acid sensor Csy1p to probe its environment, coordinate its nutritional requirements, and determine its morphological state.

scholarly journals The amino acid transporter AAP1 mediates growth and grain yield by regulating neutral amino acid uptake and reallocation in Oryza sativa

2020 ◽  
Vol 71 (16) ◽  
pp. 4763-4777 ◽  
Author(s):  
Yuanyuan Ji ◽  
Weiting Huang ◽  
Bowen Wu ◽  
Zhongming Fang ◽  
Xuelu Wang
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Grain Yield ◽  
Amino Acid Uptake ◽  
Neutral Amino Acid ◽  
Organic N ◽  
Acid Uptake ◽  
Amino Acid Permease ◽  
Short Palindromic Repeat ◽  
Exogenous Treatment

Abstract Nitrogen (N) is a major element necessary for crop yield. In most plants, organic N is primarily transported in the form of amino acids. Here, we show that amino acid permease 1 (AAP1) functions as a positive regulator of growth and grain yield in rice. We found that the OsAAP1 gene is highly expressed in rice axillary buds, leaves, and young panicles, and that the OsAAP1 protein is localized to both the plasma membrane and the nuclear membrane. Compared with the wild-type ZH11, OsAAP1 overexpression (OE) lines exhibited increased filled grain numbers as a result of enhanced tillering, while RNAi and CRISPR (clustered regularly interspaced short palindromic repeat; Osaap1) knockout lines showed the opposite phenotype. In addition, OsAAP1-OE lines had higher concentrations of neutral and acidic amino acids, but lower concentrations of basic amino acids in the straw. An exogenous treatment with neutral amino acids promoted axillary bud outgrowth more strongly in the OE lines than in the WT, RNAi, or Osaap1 lines. Transcriptome analysis of Osaap1 further demonstrated that OsAAP1 may affect N transport and metabolism, and auxin, cytokinin, and strigolactone signaling in regulating rice tillering. Taken together, these results support that increasing neutral amino acid uptake and reallocation via OsAAP1 could improve growth and grain yield in rice.

scholarly journals Isp7 Is a Novel Regulator of Amino Acid Uptake in the TOR Signaling Pathway

2014 ◽  
Vol 34 (8) ◽  
pp. 1535-1535
Author(s):  
D. Laor ◽  
A. Cohen ◽  
M. Pasmanik-Chor ◽  
V. Oron-Karni ◽  
M. Kupiec ◽  
...  
Keyword(s):  
Amino Acid ◽  
Signaling Pathway ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Tor Signaling

scholarly journals Expression study of an Amino Acid Permease-like gene in Phaseolus vulgaris L.

2020 ◽  
Vol 7 (2) ◽  
pp. 251-256
Author(s):  
Nisha Patwa ◽  
Brototi Chakraborty ◽  
Jolly Basak
Keyword(s):  
Gene Expression ◽  
Amino Acids ◽  
Amino Acid ◽  
Phaseolus Vulgaris ◽  
Critical Role ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Amino Acid Permease ◽  
Dependent Relationship ◽  
Relationship Of

Amino acid permease-like (AAP-like) gene plays a critical role in absorbing amino acids through roots in plants. A number of studies have been done on amino acids uptake in plants but till date there is no report about the expression of AAP gene in Phaseolus under field allied condition. The aim of this study is to measure the expression of AAP-like gene on alanine, glycine and proline amino acid uptake capacity in Phaseolus vulgaris at field relevant concentrations. Amongst three amino acids, a drastic significant increase of 63.15 fold in expression of AAP-like gene is observed in 50 µM alanine at 2 hr. At 50 µM of proline and 25 µM of alanine, AAP-like gene expression also shows high expression of 43.71 fold at 2 hr and 42.50 fold at 1 hr respectively. This study elucidated the dose dependent relationship of glycine, alanine and proline with the expression of AAP-like gene in amino acid transport in natural conditions in roots of P. vulgaris. Additionally, this research is also useful in identification of plants needing less surplus nitrogen additions and helpful in optimizing fertilizers by tailoring AAP gene expression to match plant uptake capacities in agriculture.

scholarly journals Molecular Imaging of Brain Tumor-Associated Epilepsy

Diagnostics ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1049
Author(s):  
Csaba Juhász ◽  
Sandeep Mittal
Keyword(s):  
Brain Tumor ◽  
Amino Acid ◽  
Brain Tumors ◽  
Treatment Strategies ◽  
Amino Acid Uptake ◽  
Seizure Outcome ◽  
Acid Uptake ◽  
Positron Emission ◽  
Oncology Practice ◽  
Glioneuronal Tumors

Epilepsy is a common clinical manifestation and a source of significant morbidity in patients with brain tumors. Neuroimaging has a pivotal role in neuro-oncology practice, including tumor detection, differentiation, grading, treatment guidance, and posttreatment monitoring. In this review, we highlight studies demonstrating that imaging can also provide information about brain tumor-associated epileptogenicity and assist delineation of the peritumoral epileptic cortex to optimize postsurgical seizure outcome. Most studies focused on gliomas and glioneuronal tumors where positron emission tomography (PET) and advanced magnetic resonance imaging (MRI) techniques can detect metabolic and biochemical changes associated with altered amino acid transport and metabolism, neuroinflammation, and neurotransmitter abnormalities in and around epileptogenic tumors. PET imaging of amino acid uptake and metabolism as well as activated microglia can detect interictal or peri-ictal cortical increased uptake (as compared to non-epileptic cortex) associated with tumor-associated epilepsy. Metabolic tumor volumes may predict seizure outcome based on objective treatment response during glioma chemotherapy. Advanced MRI, especially glutamate imaging, can detect neurotransmitter changes around epileptogenic brain tumors. Recently, developed PET radiotracers targeting specific glutamate receptor types may also identify therapeutic targets for pharmacologic seizure control. Further studies with advanced multimodal imaging approaches may facilitate development of precision treatment strategies to control brain tumor-associated epilepsy.

scholarly journals Polyribonucleotide Synthesis and Bacterial Amino Acid Uptake: the Work of Leon A. Heppel

2007 ◽  
Vol 282 (18) ◽  
pp. e13-e15
Author(s):  
Nicole Kresge ◽  
Robert D. Simoni ◽  
Robert L. Hill
Keyword(s):  
Amino Acid ◽  
Amino Acid Uptake ◽  
Acid Uptake
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