scholarly journals THOC4 regulates energy homeostasis by stabilizing TFEB mRNA during prolonged starvation

2021 ◽  
Vol 134 (6) ◽  
Author(s):  
Toshiharu Fujita ◽  
Sayaka Kubo ◽  
Tatsuya Shioda ◽  
Ayaka Tokumura ◽  
Satoshi Minami ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Energy Homeostasis ◽  
Tail Length ◽  
Prolonged Starvation ◽  
Helix Loop Helix ◽  
Additional Layer ◽  
Lysosome Biogenesis ◽  
Mrna Binding Protein ◽  
Bhlh Transcription Factors ◽  
Mrna Binding

ABSTRACT TFEB, a basic helix-loop-helix transcription factor, is a master regulator of autophagy, lysosome biogenesis and lipid catabolism. Compared to posttranslational regulation of TFEB, the regulation of TFEB mRNA stability remains relatively uncharacterized. In this study, we identified the mRNA-binding protein THOC4 as a novel regulator of TFEB. In mammalian cells, siRNA-mediated knockdown of THOC4 decreased the level of TFEB protein to a greater extent than other bHLH transcription factors. THOC4 bound to TFEB mRNA and stabilized it after transcription by maintaining poly(A) tail length. We further found that this mode of regulation was conserved in Caenorhabditiselegans and was essential for TFEB-mediated lipid breakdown, which becomes over-represented during prolonged starvation. Taken together, our findings reveal the presence of an additional layer of TFEB regulation by THOC4 and provide novel insights into the function of TFEB in mediating autophagy and lipid metabolism.

scholarly journals An Interaction between Two RNA Binding Proteins, Nab2 and Pub1, Links mRNA Processing/Export and mRNA Stability

2007 ◽  
Vol 27 (18) ◽  
pp. 6569-6579 ◽  
Author(s):  
Luciano H. Apponi ◽  
Seth M. Kelly ◽  
Michelle T. Harreman ◽  
Alexander N. Lehner ◽  
Anita H. Corbett ◽  
...  
Keyword(s):  
Mrna Stability ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Binding Protein ◽  
Tail Length ◽  
Functional Link ◽  
Mrna Binding Protein ◽  
Mrna Binding

ABSTRACT mRNA stability is modulated by elements in the mRNA transcript and their cognate RNA binding proteins. Poly(U) binding protein 1 (Pub1) is a cytoplasmic Saccharomyces cerevisiae mRNA binding protein that stabilizes transcripts containing AU-rich elements (AREs) or stabilizer elements (STEs). In a yeast two-hybrid screen, we identified nuclear poly(A) binding protein 2 (Nab2) as being a Pub1-interacting protein. Nab2 is an essential nucleocytoplasmic shuttling mRNA binding protein that regulates poly(A) tail length and mRNA export. The interaction between Pub1 and Nab2 was confirmed by copurification and in vitro binding assays. The interaction is mediated by the Nab2 zinc finger domain. Analysis of the functional link between these proteins reveals that Nab2, like Pub1, can modulate the stability of specific mRNA transcripts. The half-life of the RPS16B transcript, an ARE-like sequence-containing Pub1 target, is decreased in both nab2-1 and nab2-67 mutants. In contrast, GCN4, an STE-containing Pub1 target, is not affected. Similar results were obtained for other ARE- and STE-containing Pub1 target transcripts. Further analysis reveals that the ARE-like sequence is necessary for Nab2-mediated transcript stabilization. These results suggest that Nab2 functions together with Pub1 to modulate mRNA stability and strengthen a model where nuclear events are coupled to the control of mRNA turnover in the cytoplasm.

scholarly journals Nuclear Assembly of UGA Decoding Complexes on Selenoprotein mRNAs: a Mechanism for Eluding Nonsense-Mediated Decay?

2006 ◽  
Vol 26 (5) ◽  
pp. 1795-1805 ◽  
Author(s):  
Lucia A. de Jesus ◽  
Peter R. Hoffmann ◽  
Tanya Michaud ◽  
Erin P. Forry ◽  
Andrea Small-Howard ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Stop Codon ◽  
Elongation Factor ◽  
Protein Translation ◽  
Nonsense Mediated Decay ◽  
Nuclear Assembly ◽  
Mrna Binding Protein ◽  
Two Factors ◽  
Mrna Binding ◽  
Selenoprotein Mrnas

ABSTRACT Recoding of UGA from a stop codon to selenocysteine poses a dilemma for the protein translation machinery. In eukaryotes, two factors that are crucial to this recoding process are the mRNA binding protein of the Sec insertion sequence, SBP2, and the specialized elongation factor, EFsec. We sought to determine the subcellular localization of these selenoprotein synthesis factors in mammalian cells and thus gain insight into how selenoprotein mRNAs might circumvent nonsense-mediated decay. Intriguingly, both EFsec and SBP2 localization differed depending on the cell line but significant colocalization of the two proteins was observed in cells where SBP2 levels were detectable. We identify functional nuclear localization and export signals in both proteins, demonstrate that SBP2 undergoes nucleocytoplasmic shuttling, and provide evidence that SBP2 levels and localization may influence EFsec localization. Our results suggest a mechanism for the nuclear assembly of the selenocysteine incorporation machinery that could allow selenoprotein mRNAs to circumvent nonsense-mediated decay, thus providing new insights into the mechanism of selenoprotein translation.

scholarly journals Hypoxia up-regulates the activity of a novel erythropoietin mRNA binding protein.

1991 ◽  
Vol 266 (25) ◽  
pp. 16594-16598
Author(s):  
I.J. Rondon ◽  
L.A. MacMillan ◽  
B.S. Beckman ◽  
M.A. Goldberg ◽  
T. Schneider ◽  
...  
Keyword(s):  
Binding Protein ◽  
Mrna Binding Protein ◽  
Mrna Binding

scholarly journals Atoh8 in Development and Disease

Biology ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 136
Author(s):  
Satya Srirama Karthik Divvela ◽  
Darius Saberi ◽  
Beate Brand-Saberi
Keyword(s):  
Transcription Factors ◽  
Embryonic Development ◽  
Subcellular Location ◽  
Transcriptional Regulators ◽  
Special Group ◽  
Helix Loop Helix ◽  
Wide Range ◽  
Disease Initiation ◽  
Bhlh Transcription Factors ◽  
Bhlh Proteins

Atoh8 belongs to a large superfamily of transcriptional regulators called basic helix-loop-helix (bHLH) proteins. bHLH proteins have been identified in a wide range of organisms from yeast to humans. The members of this special group of transcription factors were found to be involved not only in embryonic development but also in disease initiation and its progression. Given their importance in several fundamental processes, the translation, subcellular location and turnover of bHLH proteins is tightly regulated. Alterations in the expression of bHLH proteins have been associated with multiple diseases also in context with Atoh8 which seems to unfold its functions as both transcriptional activator and repressor. Like many other bHLH transcription factors, so far, Atoh8 has also been observed to be involved in both embryonic development and carcinogenesis where it mainly acts as tumor suppressor. This review summarizes our current understanding of Atoh8 structure, function and regulation and its complex and partially controversial involvement in development and disease.

Increased expression of the MBP mRNA binding protein HnRNP A2 during oligodendrocyte differentiation

2004 ◽  
Vol 75 (5) ◽  
pp. 614-623 ◽  
Author(s):  
M. Maggipinto ◽  
C. Rabiner ◽  
G.J. Kidd ◽  
A.J. Hawkins ◽  
R. Smith ◽  
...  
Keyword(s):  
Binding Protein ◽  
Oligodendrocyte Differentiation ◽  
Mrna Binding Protein ◽  
Mrna Binding

scholarly journals hnRNP A1 Relocalization to the Stress Granules Reflects a Role in the Stress Response

2006 ◽  
Vol 26 (15) ◽  
pp. 5744-5758 ◽  
Author(s):  
Sonia Guil ◽  
Jennifer C. Long ◽  
Javier F. Cáceres
Keyword(s):  
Stress Response ◽  
Mammalian Cells ◽  
Stress Granules ◽  
Binding Activity ◽  
Hnrnp A1 ◽  
Mrna Metabolism ◽  
Discrete Phase ◽  
Cytoplasmic Accumulation ◽  
Mrna Binding

ABSTRACT hnRNP A1 is a nucleocytoplasmic shuttling protein that is involved in many aspects of mRNA metabolism. We have previously shown that activation of the p38 stress-signaling pathway in mammalian cells results in both hyperphosphorylation and cytoplasmic accumulation of hnRNP A1, affecting alternative splicing regulation in vivo. Here we show that the stress-induced cytoplasmic accumulation of hnRNP A1 occurs in discrete phase-dense particles, the cytoplasmic stress granules (SGs). Interestingly, mRNA-binding activity is required for both phosphorylation of hnRNP A1 and localization to SGs. We also show that these effects are mediated by the Mnk1/2 protein kinases that act downstream of p38. Finally, depletion of hnRNP A1 affects the recovery of cells from stress, suggesting a physiologically significant role for hnRNP A1 in the stress response. Our data are consistent with a model whereby hnRNP A1 recruitment to SGs involves Mnk1/2-dependent phosphorylation of mRNA-bound hnRNP A1.

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