PubMed Health⌕ Search

Biomedical subjects

T D Gilmore

Publications and source records attributed to T D Gilmore.

At least 19 recordsLinked to original sources
PubMed2006

Mutations in the NF-kappaB signaling pathway: implications for human disease.

The nuclear factor-kappa B (NF-kappaB) signaling pathway is a multi-component pathway that regulates the expression of hundreds of genes that are involved in diverse and key cellular and organismal processes, including cell proliferation, cell survival, the cellular stress response, innate immunity and inflammation. Not surprisingly, mis-regulation of the NF-kappaB pathway, either by mutation or epigenetic mechanisms, is involved in many human and animal diseases, especially ones associated with chronic inflammation, immunodeficiency or cancer. This review describes human diseases in which mutations in the components of the core NF-kappaB signaling pathway have been implicated and discusses the molecular mechanisms by which these alterations in NF-kappaB signaling are likely to contribute to the disease pathology. These mutations can be germline or somatic and include gene amplification (e.g., REL), point mutations and deletions (REL, NFKB2, IKBA, CYLD, NEMO) and chromosomal translocations (BCL-3). In addition, human genetic diseases are briefly described wherein mutations affect protein modifiers or transducers of NF-kappaB signaling or disrupt NF-kappaB-binding sites in promoters/enhancers.

Genetic Diseases, Inborn↗
PubMed2006

Introduction to NF-kappaB: players, pathways, perspectives.

This article serves as an introduction to the collection of reviews on nuclear factor-kappaB (NF-kappaB). It provides an overview of the discovery and current status of NF-kappaB as a research topic. Described are the structures, activities and regulation of the proteins in the NF-kappaB family of transcription factors. NF-kappaB signaling is primarily regulated by inhibitor kappaB (IkappaB) proteins and the IkappaB kinase complex through two major pathways: the canonical and non-canonical NF-kappaB pathways. The organization and focus of articles included in the following reviews are described, as well as likely future areas of research interest on NF-kappaB.

NF-kappa B↗
PubMed2006

Inhibitors of NF-kappaB signaling: 785 and counting.

Nuclear factor kappa B (NF-kappaB) transcription factors regulate several important physiological processes, including inflammation and immune responses, cell growth, apoptosis, and the expression of certain viral genes. Therefore, the NF-kappaB signaling pathway has also provided a focus for pharmacological intervention, primarily in situations of chronic inflammation or in cancer, where the pathway is often constitutively active and plays a key role in the disease. Now that many of the molecular details of the NF-kappaB pathway are known, it is clear that modulators of this pathway can act at several levels. As described herein, over 750 inhibitors of the NF-kappaB pathway have been identified, including a variety of natural and synthetic molecules. These compounds include antioxidants, peptides, small RNA/DNA, microbial and viral proteins, small molecules, and engineered dominant-negative or constitutively active polypeptides. Several of these molecules act as general inhibitors of NF-kappaB induction, whereas others inhibit specific pathways of induction. In addition, some compounds appear to target multiple steps in the NF-kappaB pathway. Compounds designed as specific NF-kappaB inhibitors are not yet in clinical use, but they are likely to be developed as treatments for certain cancers and neurodegenerative and inflammatory diseases. Moreover, the therapeutic and preventative effects of many natural products may, at least in part, be due to their ability to inhibit NF-kappaB.

Animals↗
PubMed2006

Mutation of an IKK phosphorylation site within the transactivation domain of REL in two patients with B-cell lymphoma enhances REL's in vitro transforming activity.

The human c-rel proto-oncogene (REL) encodes a subunit of the nuclear factor-kappaB (NF-kappaB) transcription factor. In this report, we have identified an identical point mutation in two human B-cell lymphomas (follicular (FL) and mediastinal) that changes serine (Ser)525 (TCA) to proline (Pro) (CCA) within the REL transactivation domain. This mutation was not identified in a similarly sized cohort of healthy individuals. In the mediastinal B-cell lymphoma, the mutation in REL is of germ-line origin. In both tumors, the S525P mutant allele is over-represented. REL-S525P shows enhanced in vitro transforming activity in chicken spleen cells. REL-S525P has a reduced ability to activate the human manganese superoxide dismutase (MnSOD) promoter in A293 cells; however, the MnSOD protein shows increased expression in REL-S525P-transformed chicken spleen cells as compared to wild-type REL-transformed cells. Ser525 is a site for phosphorylation by IkappaB kinase (IKK) in vitro. The S525P mutation reduces IKKalpha- and tumor necrosis factor (TNF)alpha-stimulated transactivation by a GAL4-REL protein. Furthermore, REL-S525P-transformed chicken spleen cells are more resistant to TNFalpha-induced cell death than cells transformed by wild-type REL. These results suggest that the S525P mutation contributes to the development of human B-cell lymphomas by affecting an IKKalpha-regulated transactivation activity of REL.

Amino Acid Sequence↗
PubMed2006

Good cop, bad cop: the different faces of NF-kappaB.

Complexes formed from the nuclear factor kappaB (NF-kappaB) family of transcription factors are ubiquitously expressed and are induced by a diverse array of stimuli. This results in their becoming activated in a wide variety of different settings. While the functions of NF-kappaB in many of these contexts have been the subject of intense research and are now well established, it is also clear that there is great diversity in the effects and consequences of NF-kappaB activation. NF-kappaB subunits do not necessarily regulate the same genes, in an identical manner, in all of the different circumstances in which they are induced. This review will discuss the different functions of NF-kappaB, the pathways that modulate NF-kappaB subunit activity and, in contrast to its more commonly thought of role as a promoter of cancer cell growth and survival, the ability of NF-kappaB, under some circumstances, to behave as a tumor suppressor.

Carcinogens↗
PubMed2001

Malignant transformation of primary chicken spleen cells by human transcription factor c-Rel.

Rel/NF-kappaB transcription factors control a variety of cellular processes, such as cell growth and apoptosis, that are relevant to oncogenesis, and mutations in genes encoding Rel/NF-kappaB transcription factors have been found in several human lymphoid cell cancers. In this study, we have used a sensitive cell outgrowth assay to demonstrate that wild-type human c-Rel can malignantly transform primary chicken spleen cells, and that transformation by c-Rel is accelerated by co-expression of Bc1-2. Full-length mouse c-Rel can also transform chicken spleen cells. These results are the first demonstration of a lymphoid cell malignant transforming ability for mammalian Rel/NF-kappaB transcription factors, and implicate c-Rel as a molecular target for cancer therapeutics.

Agar↗
PubMed2001

LIM domain protein Trip6 has a conserved nuclear export signal, nuclear targeting sequences, and multiple transactivation domains.

Trip6 is a member of a subfamily of LIM domain proteins, including also zyxin, LPP, Ajuba, and Hic-5, which localize primarily to focal adhesion plaques. However, in this report, we demonstrate that Trip6 is largely in the nucleus in cells treated with leptomycin B, suggesting that Trip6 shuttles between nuclear and cytoplasmic compartments and that nuclear export of Trip6 is dependent on Crm1. Consistent with this finding, we have identified a nuclear export signal (NES) in Trip6, and mutation of this NES also results in sequestration of Trip6 in the nucleus. Addition of the Trip6 NES to the nuclear v-Rel oncoprotein redirects v-Rel to the cytoplasm. Trip6 also has at least two sequences that can direct cytoplasmic beta-galactosidase to the nucleus. Using GAL4 fusion proteins and reporter gene assays, we demonstrate that Trip6 has multiple transactivation domains, including one that appears to overlap with sequences of the NES. In vitro- or in vivo-synthesized Trip6, however, does not bind to DNA-cellulose. Taken together, these results are consistent with Trip6, and other members of this LIM protein family, having a role in relaying signals between focal adhesion plaques and the nucleus.

ATPases Associated with Diverse Cellular Activitie↗
PubMed2001

Three mutations in v-Rel render it resistant to cleavage by cell-death protease caspase-3.

The retroviral oncoprotein v-Rel is a transcriptional activator in the Rel/NF-kappa B family. v-Rel causes rapidly fatal lymphomas in young chickens, and transforms and immortalizes chicken lymphoid cells in vitro. Several mutations that have enhanced the oncogenicity of v-Rel have been selected during in vitro and in vivo passage of v-Rel-containing retroviruses. In this report, we show that the C-terminal deletion and two point mutations (Asp-->Gly at residue 91 and Asp-->Asn at residue 437) in v-Rel make it resistant to cleavage by the cell-death protease caspase-3. In contrast, c-Rel, which has Asp residues at these sites, can be cleaved by caspase-3 in vitro as well as in vivo in cells induced to undergo apoptosis. We have characterized activities of v-Rel mutants with recreated single caspase-3 cleavage sites, two cleavage sites, or an introduced artificial cleavage site. All of these mutant v-Rel proteins are sensitive to caspase-3 cleavage in vitro, and show wild-type activity in terms of nuclear localization in chicken fibroblasts and DNA binding in vitro. Moreover, all caspase-3-sensitive v-Rel mutants transform chicken spleen cells in vitro and induce fatal lymphoid tumors in vivo to approximately the same extent as wild-type v-Rel. As with v-Rel mutants, caspase-3-resistant c-Rel mutants behave similarly to caspase-3-sensitive wild-type c-Rel in terms of DNA binding, transcriptional activation, in vitro transformation, and tumorigenicity. Mammalian c-Rel proteins can also be cleaved by caspase-3 in vitro, and a c-Rel mutant from a human pre-T lymphoma cell line is less sensitive than wild-type human c-Rel to cleavage by caspase-3. Taken together, these results demonstrate that specific mutations render oncogenic forms of Rel proteins resistant to cleavage by a cell-death caspase; however, the biological relevance of this resistance remains unclear. Nevertheless, to our knowledge, this is the first demonstration of mutations in caspase-3 recognition sites occurring during the evolution of an oncogenic protein.

Animals↗
PubMed2001

The chicken RelB transcription factor has transactivation sequences and a tissue-specific expression pattern that are distinct from mammalian RelB.

Rel/NF-kappaB proteins are eukaryotic transcription factors that control the expression of genes involved in a large variety of cellular processes. Rel proteins share a highly conserved DNA-binding/dimerization domain called the Rel Homology (RH) domain. We have constructed and characterized a composite cDNA encoding most of the chicken RelB transcription factor. The predicted chicken RelB protein has a high degree of sequence similarity to other vertebrate RelB proteins within the RH domain, but is much less conserved outside this domain. Chicken RelB does not bind DNA as a homodimer, but forms DNA-binding heterodimers with NF-kappaB p50 or p52. Overexpressed chicken RelB localizes to the nucleus in chicken embryo fibroblasts, and the nonconserved C-terminal sequences of chicken RelB contain a transactivation domain that functions in chicken and mouse fibroblasts. Thus, chicken RelB has functional properties similar to other vertebrate RelB proteins. However, Western blotting of diverse chicken tissues indicates that chicken RelB is more widely expressed than mammalian RelB.

Active Transport, Cell Nucleus↗
PubMed2000

Envelope-dependent transactivation by the retroviral oncoprotein v-Rel is required for efficient malignant transformation of chicken spleen cells.

The retroviral oncoprotein v-Rel is a chimeric protein that has 11 helper virus-derived Envelope (Env) amino acids (aa) at its N terminus. Within these N-terminal Env aa of v-Rel there are three aa substitutions compared to the Rev-A helper virus Env. These aa substitutions have previously been shown to impart a number of unique properties onto v-Rel, including increased transforming and transactivating ability. In this study, we have analysed the sequence requirements for the Env aa to influence several properties of v-Rel. Phe residues at aa 3 and 9 are critical for an N-terminal transactivation function of v-Rel, and the analysis of several Env mutants demonstrates that transactivation ability parallels the transforming ability of v-Rel. Substitutions of conservative aa, such as leucine and tyrosine, for Phe 3 and 9 are tolerated for transactivation in chicken embryo fibroblasts and for transformation of chicken spleen cells. In contrast, the substitution of 10 Phe residues at the N terminus of v-Rel does not enable transactivation, indicating that a distinct structure surrounding Phe-3 and Phe-9 is essential for v-Rel function. We also show that the addition of the v-Rel Env aa to the N terminus of human c-Rel can enable it to activate transcription. Taken together, these results indicate that Phe residues at positions 3 and 9 have been selected for their ability to enhance the oncogenicity of v-Rel by increasing its ability to activate transcription.

Amino Acid Substitution↗
PubMed2000

Mutant envelope residues confer a transactivation function onto N-terminal sequences of the v-Rel oncoprotein.

The retroviral oncoprotein v-Rel is a member of the Rel/ NF-kappaB family of transcription factors. v-Rel has multiple changes as compared to the proto-oncoprotein c-Rel, and these changes render v-Rel highly oncogenic in avian lymphoid cells. Previous results have shown that three mutant residues in the eleven helper virus-derived Envelope (Env) amino acids (aa) at the N-terminus of v-Rel are required for its full oncogenicity. In this report, we show that these mutant Env aa also enable sequences in the N-terminal half of v-Rel to activate transcription in yeast and chicken cells, under conditions where the analogous sequences from c-Rel either do not or only weakly activate transcription. Removal of the Env aa from v-Rel or site-directed mutations that revert the three mutant residues to the residues present in the Rev-A helper virus Env protein abolish this transactivation ability of v-Rel. Addition of mutant Env aa onto c-Rel is not sufficient to fully restore the transactivation function; other sequences in the N-terminal half of v-Rel are needed for full transactivating ability. A C terminally-truncated form of NF-kappaB p100 (p85), produced in HUT-78 human leukemic cells, also activates transcription in yeast, under conditions where the normal p52 and p100 proteins do not. Furthermore, transcriptional activation by p85 in yeast is likely to occur through N-terminal sequences. Taken together, these results are consistent with a model in which transactivation by N-terminal Rel Homology (RH) domain sequences in oncogenic Rel family proteins is influenced by sequences outside the RH domain.

Animals↗
PubMed1999

Diverse agents act at multiple levels to inhibit the Rel/NF-kappaB signal transduction pathway.

Rel/NF-kappaB transcription factors regulate several important physiological processes, including developmental processes, inflammation and immune responses, cell growth, cancer, apoptosis, and the expression of certain viral genes. Therefore, they have also been sought-after molecular targets for pharmacological intervention. As details of the Rel/NF-kappaB signal transduction pathway are revealed, it is clear that modulators of this pathway can act at several levels. Inhibitors of the Rel/NF-kappaB pathway include a variety of natural and designed molecules, including anti-oxidants, proteasome inhibitors, peptides, small molecules, and dominant-negative or constitutively active polypeptides in the pathway. Several of these molecules act as general inhibitors of Rel/NF-kappaB induction, whereas others inhibit specific pathways of induction. Inhibitors of Rel/NF-kappaB are likely to gain stature as treatments for certain cancers and neurodegenerative and inflammatory diseases.

Animals↗
PubMed1999

Multiple mutations contribute to the oncogenicity of the retroviral oncoprotein v-Rel.

The avian Rev-T retrovirus encodes the v-Rel oncoprotein, which is a member of the Rel/NF-kappaB transcription factor family. v-Rel induces a rapidly fatal lymphoma/leukemia in young birds, and v-Rel can transform and immortalize a variety of avian cell types in vitro. Although Rel/NF-kappaB transcription factors have been associated with oncogenesis in mammals, v-Rel is the only member of this family that is frankly oncogenic in animal model systems. The potent oncogenicity of v-Rel is the consequence of a number of mutations that have altered its activity and regulation: for example, certain mutations decrease its ability to be regulated by IkappaBalpha, change its DNA-binding site specificity, and endow it with new transactivation properties. The study of v-Rel will continue to increase our knowledge of how cellular Rel proteins contribute to oncogenesis by affecting cell growth, altering cell-cycle regulation, and blocking apoptosis. This review will discuss biological and molecular activities of v-Rel, with particular attention to how these activities relate to structure - function aspects of the Rel/NF-kappaB transcription factors.

Amino Acid Sequence↗
PubMed1999

Control of apoptosis by Rel/NF-kappaB transcription factors.

Apoptosis is a physiological process critical for organ development, tissue homeostasis, and elimination of defective or potentially dangerous cells in complex organisms. Apoptosis can be initiated by a wide variety of stimuli, which activate a cell suicide program that is constitutively present in most vertebrate cells. In diverse cell types, Rel/NF-kappaB transcription factors have been shown to have a role in regulating the apoptotic program, either as essential for the induction of apoptosis or, perhaps more commonly, as blockers of apoptosis. Whether Rel/NF-kappaB promotes or inhibits apoptosis appears to depend on the specific cell type and the type of inducer. An understanding of the role of Rel/NF-kappaB transcription factors in controlling apoptosis may lead to the development of therapeutics for a wide variety of human diseases, including neurodegenerative and immune diseases, and cancer.

Animals↗
PubMed1999

In vitro-translated diphtheria toxin A chain inhibits translation in wheat germ extracts: analysis of biologically active, caspase-3-resistant diphtheria toxin mutants.

The diphtheria toxin A chain (DTA) is a potent cytocidal agent that inactivates elongation factor 2. This activity of DTA inhibits protein synthesis and rapidly leads to cell death through apoptosis. In this paper, we have developed a simple in vitro assay for DTA activity in which in vitro-translated DTA is used to inhibit the translation of proteins in wheat germ extracts. Inhibition of translation by DTA is dependent on cofactor NAD+, and the analysis of an attenuated DTA mutant indicates that this in vitro assay accurately reflects the in vivo activity of DTA. We have also identified aspartic acid at residue 8 (Asp-8) of DTA as a site of cleavage by the cell-death protease caspase-3. Cleavage of DTA by caspase-3 inactivates its ability to inhibit translation in wheat germ extracts. Conservative mutations at Asp-8 render DTA resistant to cleavage by caspase-3, but only slightly affect the ability of DTA to inhibit translation in vitro. Moreover, caspase-3-resistant DTA mutants are toxic in cells in tissue culture. The in vitro assay that we describe here will be useful for the rapid analysis of DTA activity and the development of DTA mutants with altered biological properties that may be of therapeutic value. Lastly, these studies serve as a prototype for the creation of caspase-resistant effector molecules.

Amino Acid Sequence↗
PubMed1999

Characterization of mouse Trip6: a putative intracellular signaling protein.

Trip6 is a human LIM domain-containing protein that has been identified in yeast two-hybrid screens as interacting with a variety of proteins. Trip6 has been proposed to transport signals from the cell surface to the nucleus. In this report, we have characterized a mouse cDNA encoding Trip6. Mouse Trip6 is highly similar to human Trip6, especially in the C-terminal LIM domain region, and the in vitro and in vivo mouse Trip6 cDNA directs the synthesis of a polypeptide with a relative mobility of approx. 57kDa on SDS-polyacrylomide gels. Full-length Trip6 localizes to discrete cytoplasmic patches when overexpressed in chicken embryo fibroblasts, consistent with localization to focal adhesion plaques. However, deletion of the N-terminal 115 amino acids allows Trip6 to enter the nucleus of CEF. A GAL4 fusion protein containing the LIM domain region of mouse Trip6 can activate transcription in yeast and chicken fibroblasts. Our results indicate that the functional domains and properties of mouse Trip6 are highly conserved between humans and mice, and are consistent with a model in which Trip6 relays signals from the cell surface to the nucleus.

ATPases Associated with Diverse Cellular Activitie↗