scholarly journals Phosphatase activity of small C-terminal domain phosphatase 1 (SCP1) controls the stability of the key neuronal regulator RE1-silencing transcription factor (REST)

2018 ◽  
Vol 293 (43) ◽  
pp. 16851-16861 ◽  
Author(s):  
Nathaniel Tate Burkholder ◽  
Joshua E. Mayfield ◽  
Xiaohua Yu ◽  
Seema Irani ◽  
Daniel K. Arce ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Gene Silencing ◽  
Phosphatase Activity ◽  
Neurological Diseases ◽  
Regulatory Protein ◽  
Neuronal Cells ◽  
Hek293 Cells ◽  
Terminal Domain ◽  
Neuronal Gene

The RE1-silencing transcription factor (REST) is the major scaffold protein for assembly of neuronal gene silencing complexes that suppress gene transcription through regulating the surrounding chromatin structure. REST represses neuronal gene expression in stem cells and non-neuronal cells, but it is minimally expressed in neuronal cells to ensure proper neuronal development. Dysregulation of REST function has been implicated in several cancers and neurological diseases. Modulating REST gene silencing is challenging because cellular and developmental differences can affect its activity. We therefore considered the possibility of modulating REST activity through its regulatory proteins. The human small C-terminal domain phosphatase 1 (SCP1) regulates the phosphorylation state of REST at sites that function as REST degradation checkpoints. Using kinetic analysis and direct visualization with X-ray crystallography, we show that SCP1 dephosphorylates two degron phosphosites of REST with a clear preference for phosphoserine 861 (pSer-861). Furthermore, we show that SCP1 stabilizes REST protein levels, which sustains REST's gene silencing function in HEK293 cells. In summary, our findings strongly suggest that REST is a bona fide substrate for SCP1 in vivo and that SCP1 phosphatase activity protects REST against degradation. These observations indicate that targeting REST via its regulatory protein SCP1 can modulate its activity and alter signaling in this essential developmental pathway.

scholarly journals BTB Protein Keap1 Targets Antioxidant Transcription Factor Nrf2 for Ubiquitination by the Cullin 3-Roc1 Ligase

2005 ◽  
Vol 25 (1) ◽  
pp. 162-171 ◽  
Author(s):  
Manabu Furukawa ◽  
Yue Xiong
Keyword(s):  
Transcription Factor ◽  
Ring Finger ◽  
Negative Regulator ◽  
Protein Accumulation ◽  
Protein Motif ◽  
Terminal Domain ◽  
Catalytic Function ◽  
Cullin 3

ABSTRACT The concentrations and functions of many eukaryotic proteins are regulated by the ubiquitin pathway, which consists of ubiquitin activation (E1), conjugation (E2), and ligation (E3). Cullins are a family of evolutionarily conserved proteins that assemble by far the largest family of E3 ligase complexes. Cullins, via a conserved C-terminal domain, bind with the RING finger protein Roc1 to recruit the catalytic function of E2. Via a distinct N-terminal domain, individual cullins bind to a protein motif present in multiple proteins to recruit specific substrates. Cullin 3 (Cul3), but not other cullins, binds directly with BTB domains to constitute a potentially large number of BTB-CUL3-ROC1 E3 ubiquitin ligases. Here we report that the human BTB-Kelch protein Keap1, a negative regulator of the antioxidative transcription factor Nrf2, binds to CUL3 and Nrf2 via its BTB and Kelch domains, respectively. The KEAP1-CUL3-ROC1 complex promoted NRF2 ubiquitination in vitro and knocking down Keap1 or CUL3 by short interfering RNA resulted in NRF2 protein accumulation in vivo. We suggest that Keap1 negatively regulates Nrf2 function in part by targeting Nrf2 for ubiquitination by the CUL3-ROC1 ligase and subsequent degradation by the proteasome. Blocking NRF2 degradation in cells expressing both KEAP1 and NRF2 by either inhibiting the proteasome activity or knocking down Cul3, resulted in NRF2 accumulation in the cytoplasm. These results may reconcile previously observed cytoplasmic sequestration of NRF2 by KEAP1 and suggest a possible regulatory step between KEAP1-NRF2 binding and NRF2 degradation.

beta3-tubulin is directly repressed by the engrailed protein in Drosophila

Development ◽  
1997 ◽  
Vol 124 (13) ◽  
pp. 2527-2536 ◽  
Author(s):  
N. Serrano ◽  
H.W. Brock ◽  
F. Maschat
Keyword(s):  
Transcription Factor ◽  
Binding Sites ◽  
Transgenic Line ◽  
Target Genes ◽  
Regulatory Protein ◽  
Polytene Chromosomes ◽  
First Intron ◽  
Direct Target

In Drosophila, Engrailed is a nuclear regulatory protein with essential roles during embryonic development. Although Engrailed is a transcription factor, little progress has been achieved in identifying its target genes. We report here the identification of an effector gene, the beta3-tubulin gene, as a direct target of Engrailed. The cytological location of beta3-tubulin, 60C, is a strong site of Engrailed binding on polytene chromosomes. Immunostaining analysis of a transgenic line containing a P[beta3-tubulin-lacZ] construct shows an additional site of Engrailed binding at the location of the transgene. Molecular analysis allowed identification of several Engrailed binding sites, both in vitro and in vivo, within the first intron of the beta3-tubulin locus. Engrailed binding sites identified in vitro are active in larvae. Furthermore, expression of beta3-tubulin is derepressed in the ectoderm of engrailed mutant embryos. Repression of beta3-tubulin by Engrailed is also obtained when Engrailed is ectopically expressed in embryonic mesoderm. Finally, two different sets of Engrailed binding sites are shown to be involved in the early and late regulation of beta3-tubulin by Engrailed during embryogenesis.

scholarly journals ATF4 is an oxidative stress–inducible, prodeath transcription factor in neurons in vitro and in vivo

2008 ◽  
Vol 205 (5) ◽  
pp. 1227-1242 ◽  
Author(s):  
Philipp S. Lange ◽  
Juan C. Chavez ◽  
John T. Pinto ◽  
Giovanni Coppola ◽  
Chiao-Wang Sun ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Transcription Factor ◽  
Neurological Diseases ◽  
Glutathione Depletion ◽  
Bzip Transcription Factor ◽  
Behavioral Recovery ◽  
Activating Transcription Factor 4 ◽  
Death And Loss

Oxidative stress is pathogenic in neurological diseases, including stroke. The identity of oxidative stress–inducible transcription factors and their role in propagating the death cascade are not well known. In an in vitro model of oxidative stress, the expression of the bZip transcription factor activating transcription factor 4 (ATF4) was induced by glutathione depletion and localized to the promoter of a putative death gene in neurons. Germline deletion of ATF4 resulted in a profound reduction in oxidative stress–induced gene expression and resistance to oxidative death. In neurons, ATF4 modulates an early, upstream event in the death pathway, as resistance to oxidative death by ATF4 deletion was associated with decreased consumption of the antioxidant glutathione. Forced expression of ATF4 was sufficient to promote cell death and loss of glutathione. In ATF4−/− neurons, restoration of ATF4 protein expression reinstated sensitivity to oxidative death. In addition, ATF4−/− mice experienced significantly smaller infarcts and improved behavioral recovery as compared with wild-type mice subjected to the same reductions in blood flow in a rodent model of ischemic stroke. Collectively, these findings establish ATF4 as a redox-regulated, prodeath transcriptional activator in the nervous system that propagates death responses to oxidative stress in vitro and to stroke in vivo.

scholarly journals Quantitative Proteome and Transcriptome Dynamics Analysis Reveals Iron Deficiency Response Networks and Signature in Neuronal Cells

Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 484
Author(s):  
Luke Erber ◽  
Shirelle Liu ◽  
Yao Gong ◽  
Phu Tran ◽  
Yue Chen
Keyword(s):  
Transcription Factor ◽  
Iron Deficiency ◽  
Neuronal Development ◽  
Cultured Cells ◽  
Neurological Diseases ◽  
Acute Hypoxia ◽  
Cell Cycle Control ◽  
Neuronal Cells ◽  
Adaptive Responses ◽  
Study Results

Iron and oxygen deficiencies are common features in pathophysiological conditions, such as ischemia, neurological diseases, and cancer. Cellular adaptive responses to such deficiencies include repression of mitochondrial respiration, promotion of angiogenesis, and cell cycle control. We applied a systematic proteomics analysis to determine the global proteomic changes caused by acute hypoxia and chronic and acute iron deficiency (ID) in hippocampal neuronal cells. Our analysis identified over 8600 proteins, revealing similar and differential effects of each treatment on activation and inhibition of pathways regulating neuronal development. In addition, comparative analysis of ID-induced proteomics changes in cultured cells and transcriptomic changes in the rat hippocampus identified common altered pathways, indicating specific neuronal effects. Transcription factor enrichment and correlation analysis identified key transcription factors that were activated in both cultured cells and tissue by iron deficiency, including those implicated in iron regulation, such as HIF1, NFY, and NRF1. We further identified MEF2 as a novel transcription factor whose activity was induced by ID in both HT22 proteome and rat hippocampal transcriptome, thus linking iron deficiency to MEF2-dependent cellular signaling pathways in neuronal development. Taken together, our study results identified diverse signaling networks that were differentially regulated by hypoxia and ID in neuronal cells.

scholarly journals Zf9, a Kruppel-like transcription factor up-regulatedin vivoduring early hepatic fibrosis

1998 ◽  
Vol 95 (16) ◽  
pp. 9500-9505 ◽  
Author(s):  
Vlad Ratziu ◽  
Avraham Lalazar ◽  
Linda Wong ◽  
Qi Dang ◽  
Colin Collins ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Wound Repair ◽  
Cell Activation ◽  
Stellate Cell ◽  
Fetal Liver ◽  
Stellate Cells ◽  
Rat Tissues ◽  
Quiescent Cells ◽  
Terminal Domain

Wound repair in the liver induces altered gene expression in stellate cells (resident mesenchymal cells) in a process known as “activation.” A zinc finger transcription factor cDNA,zf9, was cloned from rat stellate cells activatedin vivo. Zf9 expression and biosynthesis are increased markedly in activated cellsin vivocompared with cells from normal rats (“quiescent” cells). The factor is localized to the nucleus and the perinuclear zone in activated but not quiescent cells. Zf9 mRNA also is expressed widely in nonhepatic adult rat tissues and the fetal liver. Thezf9nucleotide sequence predicts a member of the Kruppel-like family with a unique N-terminal domain rich in serine–proline clusters and leucines. The humanzf9gene maps to chromosome 10P near the telomere. Zf9 binds specifically to a DNA oligonucleotide containing a GC box motif. The N-terminal domain of Zf9 (amino acids 1–201) is transactivating in the chimeric GAL4 hybrid system. InDrosophila schneidercells, full length Zf9 transactivates a reporter construct driven by the SV40 promoter/enhancer, which contains several GC boxes. A physiologic role for Zf9 is suggested by its transactivation of a collagen α1(I) promoter reporter. Transactivation of collagen α1(I) by Zf9 is context-dependent, occurring strongly in stellate cells, modestly in Hep G2 cells, and not at all inD. schneidercells. Our results suggest that Zf9 may be an important signal in hepatic stellate cell activation after liver injury.

The GATA-E box-GATA motif in the EKLF promoter is required for in vivo expression

Blood ◽  
2000 ◽  
Vol 95 (5) ◽  
pp. 1652-1655 ◽  
Author(s):  
Kathleen P. Anderson ◽  
Scott C. Crable ◽  
Jerry B. Lingrel
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Globin Gene ◽  
Regulatory Protein ◽  
Sequence Element ◽  
Consensus Sequences ◽  
E Box ◽  
In Vivo Expression ◽  
Globin Gene Expression

The erythroid Krüppel-like factor (EKLF) is a key regulatory protein in globin gene expression. This zinc finger transcription factor is required for expression of the adult β globin gene, and it has been suggested that it plays an important role in the developmental switch from fetal γ to adult β globin gene expression. We have previously described a sequence element in the distal promoter region of the mouse EKLF gene that is critical for the expression of this transcription factor. The element consists of an E box motif flanked by 2 GATA-1 binding sites. Here we demonstrate that mutation of the E box or the GATA-1 consensus sequences eliminates expression from the EKLF promoter in transgenic mice. These results confirm the importance of this activator element for in vivo expression of the EKLF gene.

scholarly journals SpoIVB and CtpB Are Both Forespore Signals in the Activation of the Sporulation Transcription Factor σK in Bacillus subtilis

2007 ◽  
Vol 189 (16) ◽  
pp. 6021-6027 ◽  
Author(s):  
Nathalie Campo ◽  
David Z. Rudner
Keyword(s):  
Transcription Factor ◽  
Bacillus Subtilis ◽  
Mother Cell ◽  
Serine Proteases ◽  
Regulatory Protein ◽  
Signal Transduction Pathway ◽  
Proteolytic Activation ◽  
Proper Timing

ABSTRACT The proteolytic activation of the mother cell transcription factor pro-σK is controlled by a signal transduction pathway during sporulation in the bacterium Bacillus subtilis. The pro-σK processing enzyme SpoIVFB, a membrane-embedded metalloprotease, is held inactive by two other integral membrane proteins, SpoIVFA and BofA, in the mother cell membrane that surrounds the forespore. Two signaling serine proteases, SpoIVB and CtpB, trigger pro-σK processing by cleaving the regulatory protein SpoIVFA. The SpoIVB signal is absolutely required to activate pro-σK processing and is derived from the forespore compartment. CtpB is necessary for the proper timing of σK activation and was thought to be a mother cell signal. Here, we show that the ctpB gene is expressed in both the mother cell and forespore compartments but that synthesis in the forespore under the control of σG is both necessary and sufficient for the proper timing of pro-σK processing. We further show that SpoIVB cleaves CtpB in vitro and in vivo but that this cleavage does not appear to be necessary for CtpB activation. Thus, both signaling proteins are made in the forespore and independently target the same regulatory protein.

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