scholarly journals Protein Inhibitor of Activated Signal Transducer and Activator of Transcription 1 Interacts with the N-Terminal Domain of Mineralocorticoid Receptor and Represses Its Transcriptional Activity: Implication of Small Ubiquitin-Related Modifier 1 Modification

2003 ◽  
Vol 17 (12) ◽  
pp. 2529-2542 ◽  
Author(s):  
Laurent Pascual-Le Tallec ◽  
Olivier Kirsh ◽  
Marie-Christine Lecomte ◽  
Say Viengchareun ◽  
Maria-Christina Zennaro ◽  
...  
Keyword(s):  
Mineralocorticoid Receptor ◽  
Transcriptional Activity ◽  
Molecular Mechanisms ◽  
Specific Interaction ◽  
Signal Transducer ◽  
Protein Inhibitor ◽  
E3 Ligases ◽  
Terminal Domain

Abstract Molecular mechanisms underlying mineralocorticoid receptor (MR)-mediated gene expression are not fully understood but seem to largely depend upon interactions with specific coregulators. To identify novel human MR (hMR) molecular partners, yeast two-hybrid screenings performed using the N-terminal domain as bait, allowed us to isolate protein inhibitor of activated signal transducer and activator of transcription (PIAS)1 and PIASxβ, described as SUMO (small ubiquitin-related modifier) E3-ligases. Specific interaction between PIAS1 and hMR was confirmed by glutathione-S-transferase pull-down experiments and N-terminal subdomains responsible for physical contacts were delineated. Transient transfections demonstrated that PIAS1 is a corepressor of aldosterone-activated MR transactivation but has no significant effect on human glucocorticoid receptor transactivation. The agonist or antagonist nature of the bound ligand also determines PIAS1 corepressive action. We provided evidence that PIAS1 conjugated SUMO-1 to hMR both in vitro and in vivo. Deciphering the unique sumoylation pattern of hMR, which possesses five consensus SUMO-1 binding sites, by combinatorial lysine substitutions, revealed a major impact of sumoylation on hMR properties. Using a murine mammary tumor virus promoter, PIAS1 action was independent of sumoylation whereas with glucocorticoid response element promoter, PIAS1 corepressive action depended on hMR sumoylation status. Taken together, our results identify a novel function for PIAS1 which interacts with the N-terminal domain of hMR and represses its ligand-dependent transcriptional activity, at least in part, through SUMO modifications.

scholarly journals LOXL1 modulates the malignant progression of colorectal cancer by inhibiting the transcriptional activity of YAP

2020 ◽  
Author(s):  
Lin Hu ◽  
Jing Wang ◽  
Yunliang Wang ◽  
Linpeng Wu ◽  
Chao Wu ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Lines ◽  
Cancer Progression ◽  
Colony Formation ◽  
Transcriptional Activity ◽  
Tumour Growth ◽  
Molecular Mechanisms ◽  
Migration And Invasion

Abstract Background: LOX-like 1 (LOXL1) is a lysyl oxidase, and emerging evidence has revealed its effect on malignant cancer progression. However, its role in colorectal cancer (CRC) and the underlying molecular mechanisms have not yet been elucidated. Methods: LOXL1 expression in colorectal cancer was detected by immunohistochemistry, western blotting and real-time PCR. In vitro , colony formation, wound healing, migration and invasion assays were performed to investigate the effects of LOXL1 on cell proliferation, migration and invasion. In vivo , metastasis models and mouse xenografts were used to assess tumorigenicity and metastasis ability. Molecular biology experiments were utilized to reveal the underlying mechanisms by which LOXL1 modulates the Hippo pathway. Results: LOXL1 was highly expressed in normal colon tissues compared with cancer tissues. In vitro, silencing LOXL1 in CRC cell lines dramatically enhanced migration, invasion, and colony formation, while overexpression of LOXL1 exerted the opposite effects. The results of the in vivo experiments demonstrated that the overexpression of LOXL1 in CRC cell lines drastically inhibited metastatic progression and tumour growth. Mechanistically, LOXL1 inhibited the transcriptional activity of Yes-associated protein (YAP) by interacting with MST1/2 and increasing the phosphorylation of MST1/2. Conclusions: LOXL1 may function as an important tumour suppressor in regulating tumour growth, invasion and metastasis via negative regulation of YAP activity.

MOZ and MOZ-CBP Cooperate with NFκB To Induce Expression of NFκB-Dependent Genes.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 887-887 ◽  
Author(s):  
Edward M. Chan ◽  
Rebecca J. Chan ◽  
Elisha M. Comer ◽  
Robert J. Goulet ◽  
Colin D. Crean ◽  
...  
Keyword(s):  
Stem Cells ◽  
Transcriptional Activity ◽  
Zinc Finger Protein ◽  
Alternative Mechanism ◽  
Creb Binding Protein ◽  
Hematopoietic Stem ◽  
Terminal Domain ◽  
Acute Myeloid

Abstract Although monocytic zinc finger protein (MOZ/MYST3) maintains normal hematopoietic stem cells, its fusion to the coactivator CREB-binding protein (CBP/CREBBP) induces acute myeloid leukemia (AML). Since leukemic stem cells in AML often exhibit excessive signal-dependent activity of the transcription factor NFκB, we hypothesized that cooperation between NFκB and MOZ-CBP represents an alternative mechanism for enhancing NFκB transcriptional activity. In reporter assays, MOZ and CBP separately induce transcription from the NFκB-dependent interleukin-8 promoter; however, these two proteins together markedly activate its expression. Although MOZ has less potent transcriptional activity than MOZ-CBP, both proteins cooperate with steroid receptor coactivator-1 (SRC1/NCOA1) to activate transcription. Since cooperation between MOZ-CBP and SRC1 is strongly reminiscent of the interaction between MOZ-TIF2/SRC2 and CBP required to induce AML (Deguchi et al, 2003), these findings suggest that MYST family fusion proteins may assemble a conserved leukemogenic transcriptional complex composed of a MYST protein (MOZ, MORF), molecular integrator (CBP, p300), and nuclear receptor coactivator (SRC1, TIF2/SRC2). MOZ also induces multiple NFκB-dependent viral promoters. Importantly, MOZ associates in a protein complex with the DNA-binding p65/RELA subunit of NFκB in vivo and interacts directly with p65 in vitro. Whereas deletion of the leukemia-associated protein (LAP/PHD) or MYST domains decreases the transcriptional activity of MOZ, deletion of either the acidic domain or C-terminal domain completely abrogates its activity. Since the C-terminal domain is absent from MOZ-CBP, these results indicate that the potent transcriptional activity of MOZ-CBP represents a gain-of-function property derived from the retained portion of CBP. Collectively, these studies not only demonstrate that MOZ and MOZ-CBP cooperate with NFκB to enhance expression of NFκB-dependent promoters but also suggest that aberrant interaction between MOZ-CBP and NFκB may play an important role in the pathogenesis of certain acute myeloid leukemias.

PIAS proteins promote SUMO-1 conjugation to STAT1

Blood ◽  
2003 ◽  
Vol 102 (9) ◽  
pp. 3311-3313 ◽  
Author(s):  
Daniela Ungureanu ◽  
Sari Vanhatupa ◽  
Noora Kotaja ◽  
Jie Yang ◽  
Saara Aittomäki ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Posttranslational Modifications ◽  
Interferon Γ ◽  
Regulatory Function ◽  
Cytokine Signaling ◽  
Signal Transducer ◽  
Protein Inhibitor ◽  
Ifn Γ

AbstractSignal transducer and activator of transcription 1 (STAT1) is a critical mediator of interferon-γ (IFN-γ)–induced transcription that is regulated through posttranslational modifications and through transacting proteins such as protein inhibitor of activated STAT1 (PIAS1). PIAS proteins have been shown to function as E3-type small ubiquitin-like modifier (SUMO) ligases, and sumoylation has been identified as a modulatory mechanism for several transcription factors. Here we show that STAT1 is subject to SUMO-1 modification, and sumoylation occurs in vivo and in vitro at a single, evolutionary conserved amino acid residue Lys703. Members of the PIAS family of proteins were found to strongly stimulate sumoylation of STAT1. Furthermore, activation of STAT1 by IFN-γ or pervanadate induced SUMO-1 conjugation. Mutation of Lys703 in STAT1 resulted in increased IFN-γ–mediated transactivation, suggesting a negative regulatory function for sumoylation. These results indicate that STAT1 is covalently modified by SUMO-1 in cytokine signaling and that PIAS proteins promote SUMO-1 conjugation to STAT1.

PIAS proteins as regulators of small ubiquitin-related modifier (SUMO) modifications and transcription

2007 ◽  
Vol 35 (6) ◽  
pp. 1405-1408 ◽  
Author(s):  
J.J. Palvimo
Keyword(s):  
Transcription Factors ◽  
Transcriptional Activity ◽  
Ring Finger ◽  
Regulatory Proteins ◽  
Signal Transducer ◽  
Protein Inhibitor ◽  
E3 Ligases ◽  
Stat Proteins ◽  
Transcription Complexes ◽  
Attachment Factor

Transcriptional activity of signal-dependent transcription factors, including nuclear receptors, relies on interacting co-regulator proteins, many of which possess protein-modifying activity. SUMOs (small ubiquitin-related modifiers) and their conjugation pathway components act as co-regulator proteins for numerous transcription factors that also are often targets for SUMO modification. PIAS [protein inhibitor of activated STAT (signal transducer and activator of transcription)] proteins promote SUMOylation in a manner that resembles the action of RING-type ubiquitin E3 ligases. PIAS proteins were initially named for their ability to interact with STAT proteins and inhibit their activity, but their interactions and functions are not restricted to the STATs. Moreover, PIAS proteins do not operate merely as SUMO E3s, since their co-regulator effects are often independent of their RING finger but dependent on their SIM (SUMO-interacting motif) or SAP (scaffold attachment factor-A/B/acinus/PIAS) domain capable of interacting with DNA. The modulator activity imparted by the PIAS/SUMO system involves altered subnuclear targeting and/or assembly of transcription complexes. PIAS proteins may act as platforms that facilitate both removal and recruitment of other regulatory proteins in the transcription complexes.

scholarly journals LOXL1 modulates the malignant progression of colorectal cancer by inhibiting the transcriptional activity of YAP

2020 ◽  
Author(s):  
Lin Hu ◽  
Jing Wang ◽  
Yunliang Wang ◽  
Linpeng Wu ◽  
Chao Wu ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Lines ◽  
Colony Formation ◽  
Transcriptional Activity ◽  
Tumour Growth ◽  
Molecular Mechanisms ◽  
Malignant Progression ◽  
Migration And Invasion

Abstract Background LOX-like 1 (LOXL1), as a lysyl oxidase, emerging evidences revealed the effect in cancer malignant progression. However, its role in colorectal cancer (CRC) and the underlying molecular mechanisms have not yet been elucidated. Methods LOXL1 expression in colorectal cancer was detected by immunohistochemistry, western blot and real-time PCR. In vitro , colony formation assay, wound healing assay, migration and invasion experiment were performed to investigate the effects of LOXL1 in cell proliferation, migration and invasion, respectively. In vivo , metastasis models and mouse xenograft were used to determine tumorigenicity and metastasis ability. Molecular biology experiments were utilized to reveal the underlying mechanisms of LOXL1 modulating Hippo pathway. Results LOXL1 is highly expressed in normal colon tissues compared with cancer tissues. In vitro, Silencing LOXL1 in CRC cell lines dramatically enhanced migration, invasion, and colony formation, while overexpression of LOXL1 manifested the opposite effects. Results of the in vivo experiments demonstrated that the enforced expression of LOXL1 in CRC cell lines had drastically inhibited the progression of metastasis and tumour growth. Mechanistically, LOXL1 inhibited the transcriptional activity of Yes-associated protein (YAP) was through interaction with MST1/2 and increasing the phosphorylation of MST1/2. Conclusions LOXL1 may function as an important tumour suppressor in regulating tumour growth, invasion and metastasis via negative regulating of YAP activity.

scholarly journals Analysis of the Mouse CSF-1 Gene Promoter in a Transgenic Mouse Model1

2003 ◽  
Vol 51 (7) ◽  
pp. 941-949 ◽  
Author(s):  
Sherry L. Abboud ◽  
Maria Bunegin ◽  
Nandini Ghosh-Choudhury ◽  
Kathleen Woodruff
Keyword(s):  
Gene Expression ◽  
Transgenic Mice ◽  
Transgene Expression ◽  
Transcriptional Activity ◽  
Molecular Mechanisms ◽  
Tissue Expression ◽  
Cellular Level ◽  
Liver And Kidney

CSF-1 stimulates monocyte and osteoclast populations. However, the molecular mechanisms involved in regulating CSF-1 gene expression are unclear. To identify regulatory regions that control normal CSF-1 gene expression, a −774/+183-bp fragment of the murine CSF-1 promoter was analyzed in vitro and in vivo. Transcriptional activity was high in cultured osteoblasts that express CSF-1 mRNA compared to ARH-77 B cells that lack CSF-1 gene expression. Transient transfection of osteoblasts with promoter deletion constructs showed that the −774-bp fragment conferred the highest transcriptional activity and contained activator and repressor sequences. To assess the ability of the CSF-1 promoter to confer normal tissue expression of CSF-1, transgenic mice containing the −774/+183-bp region driving the E. coli β-galactosidase (lacZ) reporter gene were generated. β-Gal analysis of whole tissue extracts showed transgene expression in all tissues tested except liver and kidney. At the cellular level, the pattern of β-gal expression in the spleen, thymus, bone, lung, and testes of adult transgenic mice mimicked normal endogenous CSF-1 mRNA expression in non-transgenic littermates detected by in situ hybridization. This region also directed appropriate transgene expression to sites in other tissues known to synthesize CSF-1, with the exception of the liver and kidney. These findings indicate that the −774-bp fragment contains cis-acting elements sufficient to direct CSF-1 gene expression in many tissues. CSF-1 promoter/lacZ mice may be useful for studying the transcriptional mechanisms involved in regulating CSF-1 gene expression in tissues throughout development.

scholarly journals LOXL1 modulates the malignant progression of colorectal cancer by inhibiting the transcriptional activity of YAP

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Lin Hu ◽  
Jing Wang ◽  
Yunliang Wang ◽  
Linpeng Wu ◽  
Chao Wu ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Lines ◽  
Cancer Progression ◽  
Colony Formation ◽  
Transcriptional Activity ◽  
Tumour Growth ◽  
Molecular Mechanisms ◽  
Migration And Invasion

Abstract Background LOX-like 1 (LOXL1) is a lysyl oxidase, and emerging evidence has revealed its effect on malignant cancer progression. However, its role in colorectal cancer (CRC) and the underlying molecular mechanisms have not yet been elucidated. Methods LOXL1 expression in colorectal cancer was detected by immunohistochemistry, western blotting and real-time PCR. In vitro, colony formation, wound healing, migration and invasion assays were performed to investigate the effects of LOXL1 on cell proliferation, migration and invasion. In vivo, metastasis models and mouse xenografts were used to assess tumorigenicity and metastasis ability. Molecular biology experiments were utilized to reveal the underlying mechanisms by which LOXL1 modulates the Hippo pathway. Results LOXL1 was highly expressed in normal colon tissues compared with cancer tissues. In vitro, silencing LOXL1 in CRC cell lines dramatically enhanced migration, invasion, and colony formation, while overexpression of LOXL1 exerted the opposite effects. The results of the in vivo experiments demonstrated that the overexpression of LOXL1 in CRC cell lines drastically inhibited metastatic progression and tumour growth. Mechanistically, LOXL1 inhibited the transcriptional activity of Yes-associated protein (YAP) by interacting with MST1/2 and increasing the phosphorylation of MST1/2. Conclusions LOXL1 may function as an important tumour suppressor in regulating tumour growth, invasion and metastasis via negative regulation of YAP activity. Graphical abstract

scholarly journals Intramolecular interactions between the AF3 domain and the C-terminus of the human progesterone receptor are mediated through two LXXLL motifs

2004 ◽  
Vol 32 (3) ◽  
pp. 843-857 ◽  
Author(s):  
X Dong ◽  
SJ Lye ◽  
Keyword(s):  
Progesterone Receptor ◽  
Transcriptional Activity ◽  
Molecular Mechanisms ◽  
Direct Interaction ◽  
Intramolecular Interactions ◽  
Dependent Manner ◽  
C Terminus ◽  
Human Progesterone Receptor

The human progesterone receptor (PR) exists in two major forms, PRA and PRB, which differentially regulate gene transcription in a cell- and promoter-specific manner. The molecular mechanisms underlying this differential transcriptional activity have been attributed to the presence of a unique AF3 domain within PRB that may result in the two isoforms adopting different protein conformations. We demonstrate here that in myometrial cells, PRB exhibits strong progesterone-dependent transcriptional activity that is dependent on the presence of two LXXLL motifs within the AF3 domain. In vitro and in vivo protein interaction assays indicate that these motifs mediate the direct interaction between the AF3 domain and C-PR in a progesterone-dependent manner. Mutation of either of the LXXLL motifs or deletion of the last 30 amino acids within the C-terminus disrupts this interaction and progesterone-dependent transcriptional activity of PRB. Members of the p160 family of co-activators (such as GRIP-1) also interact with C-PR through their LXXLL motifs. However, GRIP-1 does not compete with AF3 but rather acts to synergize these two transactivation domains. Our data suggest that a failure to form an appropriate AF3-C-terminus interaction results in an inability of co-activators to induce maximal PR-dependent transactivation. The absence of an AF3 domain within PRA may account for its inability to activate progesterone-responsive genes, as well as its actions as a dominant trans-repressor.

Calpain is a signal transducer and activator of transcription (STAT) 3 and STAT5 protease

Blood ◽  
2002 ◽  
Vol 99 (5) ◽  
pp. 1850-1852 ◽  
Author(s):  
Atsushi Oda ◽  
Hiroshi Wakao ◽  
Hiroyoshi Fujita
Keyword(s):  
Genetic Engineering ◽  
Cysteine Protease ◽  
Posttranslational Modification ◽  
Dominant Negative ◽  
Signal Transducer ◽  
Terminal Domain ◽  
Carboxy Terminal Domain ◽  
Carboxy Terminal

Truncation of signal transducer and activator of transcription (STAT) 5 at the carboxy-terminal domain, either by genetic engineering or by proteolytic cleavage, results in generation of dominant-negative forms. A nuclear serine protease expressed in the myeloid precursor cells is known to mediate this cleavage, but other proteases responsible for this reaction were unknown. We found that calpain, a ubiquitously expressed cysteine protease, also trims STAT5 in vivo and in vitro, within the carboxy-terminal domain. Nuclear element is not necessary for calpain-mediated STAT5 cleavage, since this process occurs in platelets. We also found that STAT3 is a substrate for calpain in vivo and in vitro, indicating that calpain-mediated cleavage is a common feature of STAT3 and STAT5. Thus, our study reveals a novel pathway for posttranslational modification of STAT3 and STAT5.

scholarly journals Hypothalamic progesterone receptor-A mediates gonadotropin surges, self priming and receptivity in estrogen-primed female mice

2007 ◽  
Vol 38 (1) ◽  
pp. 35-50 ◽  
Author(s):  
Mellodee M White ◽  
Irene Sheffer ◽  
Jennifer Teeter ◽  
Ede Marie Apostolakis
Keyword(s):  
Progesterone Receptor ◽  
Reproductive Behavior ◽  
Transcriptional Activity ◽  
Molecular Mechanisms ◽  
Arcuate Nucleus ◽  
Preoptic Area ◽  
Female Mice ◽  
Hypothalamic Function

Ovarian progesterone (Prog) is an essential steroid hormone for the secretion of GnRH and reproductive behavior. It exerts primary effects through the progesterone receptor (PR). When analyzed separately in vitro, PR isoforms (PR-A, PR-B) display striking differences in transcriptional activity. The present study was undertaken to determine the in vivo impact of each isoform on hypothalamic function in female mice with ablation of a single isoform, either PR-A or PR-B. To this end, we used single-cell RNA analyses, reverse transcriptase real-time (q)PCR mRNA analyses of punched-out tissue, immunohistochemistry, and reproductive behavior. We provide evidence for the requirement of PR-A in individual ventrolateral ventromedial nucleus (vlVMN) neurons for Prog-facilitated proceptive and receptive behaviors in estrogen benzoate (EB)-primed females and the reciprocal male interactions. We clarify histological and molecular mechanisms of PR isoform activity by showing that (1) PR-A is predominant in individual vlVMN neurons controlling female lordosis circuitry, whilst (2) PR-B is predominant in those VMN subdivisions that provide for amplification of PR-A activity. We go on to demonstrate that PR-A is dominant in the anteroventral periventricular nucleus but not the arcuate nucleus that feed fibers into and around the VMN. In the medial preoptic area, high levels of GnRH RNA in EB-primed PR-A-expressing mice were seen coincident with increased plasma LH levels. Two consecutive GnRH pulses enhanced LH only in primed PR-A-expressing females. In all, the findings are consistent with the hypothesis that hypothalamic PR-A-mediated genomic activities result in reproductive behavior coordinated with ovulation.

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