scholarly journals TFEB controls retromer expression in response to nutrient availability

2019 ◽  
Vol 218 (12) ◽  
pp. 3954-3966 ◽  
Author(s):  
Rachel Curnock ◽  
Alessia Calcagni ◽  
Andrea Ballabio ◽  
Peter J. Cullen

Endosomal recycling maintains the cell surface abundance of nutrient transporters for nutrient uptake, but how the cell integrates nutrient availability with recycling is less well understood. Here, in studying the recycling of human glutamine transporters ASCT2 (SLC1A5), LAT1 (SLC7A5), SNAT1 (SLC38A1), and SNAT2 (SLC38A2), we establish that following amino acid restriction, the adaptive delivery of SNAT2 to the cell surface relies on retromer, a master conductor of endosomal recycling. Upon complete amino acid starvation or selective glutamine depletion, we establish that retromer expression is upregulated by transcription factor EB (TFEB) and other members of the MiTF/TFE family of transcription factors through association with CLEAR elements in the promoters of the retromer genes VPS35 and VPS26A. TFEB regulation of retromer expression therefore supports adaptive nutrient acquisition through endosomal recycling.

2018 ◽  
Vol 115 (8) ◽  
pp. E1829-E1838 ◽  
Author(s):  
Caia D. S. Duncan ◽  
María Rodríguez-López ◽  
Phil Ruis ◽  
Jürg Bähler ◽  
Juan Mata

Eukaryotes respond to amino acid starvation by enhancing the translation of mRNAs encoding b-ZIP family transcription factors (GCN4 in Saccharomyces cerevisiae and ATF4 in mammals), which launch transcriptional programs to counter this stress. This pathway involves phosphorylation of the eIF2 translation factor by Gcn2-protein kinases and is regulated by upstream ORFs (uORFs) in the GCN4/ATF4 5′ leaders. Here, we present evidence that the transcription factors that mediate this response are not evolutionarily conserved. Although cells of the fission yeast Schizosaccharomyces pombe respond transcriptionally to amino acid starvation, they lack clear Gcn4 and Atf4 orthologs. We used ribosome profiling to identify mediators of this response in S. pombe, looking for transcription factors that behave like GCN4. We discovered a transcription factor (Fil1) translationally induced by amino acid starvation in a 5′ leader and Gcn2-dependent manner. Like Gcn4, Fil1 is required for the transcriptional response to amino acid starvation, and Gcn4 and Fil1 regulate similar genes. Despite their similarities in regulation, function, and targets, Fil1 and Gcn4 belong to different transcription factor families (GATA and b-ZIP, respectively). Thus, the same functions are performed by nonorthologous proteins under similar regulation. These results highlight the plasticity of transcriptional networks, which maintain conserved principles with nonconserved regulators.


2004 ◽  
Vol 24 (3) ◽  
pp. 1365-1377 ◽  
Author(s):  
Hao-Yuan Jiang ◽  
Sheree A. Wek ◽  
Barbara C. McGrath ◽  
Dan Lu ◽  
Tsonwin Hai ◽  
...  

ABSTRACT In response to environmental stress, cells induce a program of gene expression designed to remedy cellular damage or, alternatively, induce apoptosis. In this report, we explore the role of a family of protein kinases that phosphorylate eukaryotic initiation factor 2 (eIF2) in coordinating stress gene responses. We find that expression of activating transcription factor 3 (ATF3), a member of the ATF/CREB subfamily of basic-region leucine zipper (bZIP) proteins, is induced in response to endoplasmic reticulum (ER) stress or amino acid starvation by a mechanism requiring eIF2 kinases PEK (Perk or EIF2AK3) and GCN2 (EIF2AK4), respectively. Increased expression of ATF3 protein occurs early in response to stress by a mechanism requiring the related bZIP transcriptional regulator ATF4. ATF3 contributes to induction of the CHOP transcriptional factor in response to amino acid starvation, and loss of ATF3 function significantly lowers stress-induced expression of GADD34, an eIF2 protein phosphatase regulatory subunit implicated in feedback control of the eIF2 kinase stress response. Overexpression of ATF3 in mouse embryo fibroblasts partially bypasses the requirement for PEK for induction of GADD34 in response to ER stress, further supporting the idea that ATF3 functions directly or indirectly as a transcriptional activator of genes targeted by the eIF2 kinase stress pathway. These results indicate that ATF3 has an integral role in the coordinate gene expression induced by eIF2 kinases. Given that ATF3 is induced by a very large number of environmental insults, this study supports involvement of eIF2 kinases in the coordination of gene expression in response to a more diverse set of stress conditions than previously proposed.


2010 ◽  
Vol 30 (13) ◽  
pp. 3299-3309 ◽  
Author(s):  
Thorsten Pfirrmann ◽  
Stijn Heessen ◽  
Deike J. Omnus ◽  
Claes Andréasson ◽  
Per O. Ljungdahl

ABSTRACT Extracellular amino acids induce the yeast SPS sensor to endoproteolytically cleave transcription factors Stp1 and Stp2 in a process termed receptor-activated proteolysis (RAP). Ssy5, the activating endoprotease, is synthesized with a large N-terminal prodomain and a C-terminal chymotrypsin-like catalytic (Cat) domain. During biogenesis, Ssy5 cleaves itself and the prodomain and Cat domain remain associated, forming an inactive primed protease. Here we show that the prodomain is a potent inhibitor of Cat domain activity and that its inactivation is a requisite for RAP. Accordingly, amino acid-induced signals trigger proteasome-dependent degradation of the prodomain. A mutation that stabilizes the prodomain prevents Stp1 processing, whereas destabilizing mutations lead to constitutive RAP-independent Stp1 processing. We fused a conditional degron to the prodomain to synthetically reprogram the amino acid-responsive SPS signaling pathway, placing it under temperature control. Our results define a regulatory mechanism that is novel for eukaryotic proteases functioning within cells.


Genetics ◽  
2004 ◽  
Vol 166 (4) ◽  
pp. 1727-1739 ◽  
Author(s):  
Fadi Abdel-Sater ◽  
Ismaïl Iraqui ◽  
Antonio Urrestarazu ◽  
Bruno André

Abstract Yeast cells respond to the presence of amino acids in their environment by inducing transcription of several amino acid permease genes including AGP1, BAP2, and BAP3. The signaling pathway responsible for this induction involves Ssy1, a permease-like sensor of external amino acids, and culminates with proteolytic cleavage and translocation to the nucleus of the zinc-finger proteins Stp1 and Stp2, the lack of which abolishes induction of BAP2 and BAP3. Here we show that Stp1—but not Stp2—plays an important role in AGP1 induction, although significant induction of AGP1 by amino acids persists in stp1 and stp1 stp2 mutants. This residual induction depends on the Uga35/Dal81 transcription factor, indicating that the external amino acid signaling pathway activates not only Stp1 and Stp2, but also another Uga35/Dal81-dependent transcriptional circuit. Analysis of the AGP1 gene’s upstream region revealed that Stp1 and Uga35/Dal81 act synergistically through a 21-bp cis-acting sequence similar to the UASAA element previously found in the BAP2 and BAP3 upstream regions. Although cells growing under poor nitrogen-supply conditions display much higher induction of AGP1 expression than cells growing under good nitrogen-supply conditions, the UASAA itself is totally insensitive to nitrogen availability. Nitrogen-source control of AGP1 induction is mediated by the GATA factor Gln3, likely acting through adjacent 5′-GATA-3′ sequences, to amplify the positive effect of UASAA. Our data indicate that Stp1 may act in combination with distinct sets of transcription factors, according to the gene context, to promote induction of transcription in response to external amino acids. The data also suggest that Uga35/Dal81 is yet another transcription factor under the control of the external amino acid sensing pathway. Finally, the data show that the TOR pathway mediating global nitrogen control of transcription does not interfere with the external amino acid signaling pathway.


HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 480e-480
Author(s):  
Nathan E. Lange ◽  
Michael S. Reid ◽  
Victoriano Valpuesta ◽  
Consuelo Guerrero ◽  
Miguel A. Botella

As in many commercially important flowers, especially the monocotyledonous geophytes, senescence of the ephemeral daylily flower (Hemerocallis) does not involve ethylene. By differentially screening a cDNA library constructed from mRNA extracted from daylily petals in the earliest stages of senescence, clones were isolated whose transcription is up-regulated coordinately with the onset of senescence. One of these clones, sen12, was found to be a transcription factor. The deduced amino acid sequence of sen12 contains a MADS-box and an associated K-box similar to transcription factors suggested to control floral morphogenesis in a variety of different species. Northern blot hybridization showed sen12 to be highly upregulated before and during visible flower senescence. The expression of homologous genes during senescence of other flowers will be reported.


2021 ◽  
Author(s):  
Liqun Luo ◽  
Qijing Xie ◽  
Jiefu Li ◽  
Hongjie Li ◽  
Namrata Udeshi ◽  
...  

Abstract Transcription factors are central commanders specifying cell fate, morphology, and physiology while cell-surface proteins execute these commands through interaction with cellular environment. In developing neurons, it is presumed that transcription factors control wiring specificity through regulation of cell-surface protein expression. However, the number and identity of cell-surface protein(s) a transcription factor regulates remain largely unclear1,2. Also unknown is whether a transcription factor regulates the same or different cell-surface proteins in different neuron types to specify their connectivity. Here we use a lineage-defining transcription factor, Acj6 (ref. 3), to investigate how it controls precise dendrite targeting of Drosophila olfactory projection neurons (PNs). Quantitative cell-surface proteomic profiling of wild-type and acj6 mutant PNs in intact developing brains and a proteome-informed genetic screen identified PN surface proteins that execute Acj6-regulated wiring decisions. These include canonical cell adhesion proteins and proteins previously not associated with wiring, such as the mechanosensitive ion channel Piezo—whose channel activity is dispensable for its wiring function. Comprehensive genetic analyses revealed that Acj6 employs unique sets of cell-surface proteins in different PN types for dendrite targeting. Combinatorial expression of Acj6 wiring executors rescued acj6 mutant phenotypes with higher efficacy and breadth than expression of individual executors. Thus, a key transcription factor controls wiring specificity of different neuron types by specifying distinct combinatorial expression of cell-surface executors.


2002 ◽  
Vol 22 (15) ◽  
pp. 5395-5404 ◽  
Author(s):  
Revital Shemer ◽  
Ariella Meimoun ◽  
Tsvi Holtzman ◽  
Daniel Kornitzer

ABSTRACT The yeast transcription factor Gcn4 is regulated by amino acid starvation at the levels of both protein synthesis and stability. Gcn4 degradation depends on the ubiquitination complex SCFCDC4 and requires phosphorylation by the cyclin-dependent kinase Pho85. Here, we show that Pcl5 is the Pho85 cyclin specifically required for Gcn4 degradation. PCL5 is itself induced by Gcn4 at the level of transcription. However, even when PCL5 is constitutively overexpressed, Pho85-associated Gcn4 phosphorylation activity is reduced in starved cells and Gcn4 degradation is decreased. Under these conditions, the Pcl5 protein disappears because of rapid constitutive turnover. We suggest that, by virtue of its constitutive metabolic instability, Pcl5 may be a sensor of cellular protein biosynthetic capacity. The fact that PCL5 is transcriptionally induced in the presence of Gcn4 suggests that it is part of a homeostatic mechanism that reduces Gcn4 levels upon recovery from starvation.


2009 ◽  
Vol 29 (24) ◽  
pp. 6515-6526 ◽  
Author(s):  
Cédric Chaveroux ◽  
Céline Jousse ◽  
Yoan Cherasse ◽  
Anne-Catherine Maurin ◽  
Laurent Parry ◽  
...  

ABSTRACT It has been well established that amino acid availability can control gene expression. Previous studies have shown that amino acid depletion induces transcription of the ATF3 (activation transcription factor 3) gene through an amino acid response element (AARE) located in its promoter. This event requires phosphorylation of activating transcription factor 2 (ATF2), a constitutive AARE-bound factor. To identify the signaling cascade leading to phosphorylation of ATF2 in response to amino acid starvation, we used an individual gene knockdown approach by small interfering RNA transfection. We identified the mitogen-activated protein kinase (MAPK) module MEKK1/MKK7/JNK2 as the pathway responsible for ATF2 phosphorylation on the threonine 69 (Thr69) and Thr71 residues. Then, we progressed backwards up the signal transduction pathway and showed that the GTPase Rac1/Cdc42 and the protein Gα12 control the MAPK module, ATF2 phosphorylation, and AARE-dependent transcription. Taken together, our data reveal a new signaling pathway activated by amino acid starvation leading to ATF2 phosphorylation and subsequently positively affecting the transcription of amino acid-regulated genes.


2003 ◽  
Vol 14 (10) ◽  
pp. 4272-4284 ◽  
Author(s):  
Gerhard H. Braus ◽  
Olav Grundmann ◽  
Stefan Brückner ◽  
Hans-Ulrich Mösch

In baker's yeast Saccharomyces cerevisiae, cell-cell and cell-surface adhesion are required for haploid invasive growth and diploid pseudohyphal development. These morphogenetic events are induced by starvation for glucose or nitrogen and require the cell surface protein Flo11p. We show that amino acid starvation is a nutritional signal that activates adhesive growth and expression of FLO11 in both haploid and diploid strains in the presence of glucose and ammonium, known suppressors of adhesion. Starvation-induced adhesive growth requires Flo11p and is under control of Gcn2p and Gcn4p, elements of the general amino acid control system. Tpk2p and Flo8p, elements of the cAMP pathway, are also required for activation but not Ste12p and Tec1p, known targets of the mitogen-activated protein kinase cascade. Promoter analysis of FLO11 identifies one upstream activation sequence (UASR) and one repression site (URS) that confer regulation by amino acid starvation. Gcn4p is not required for regulation of the UASRby amino acid starvation, but seems to be indirectly required to overcome the negative effects of the URS on FLO11 transcription. In addition, Gcn4p controls expression of FLO11 by affecting two basal upstream activation sequences (UASB). In summary, our study suggests that amino acid starvation is a nutritional signal that triggers a Gcn4p-controlled signaling pathway, which relieves repression of FLO11 gene expression and induces adhesive growth.


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