Publications by authors named "Tom K Kerppola"

Cells must control genes that are induced by virus infection to mitigate deleterious consequences of inflammation. We investigated the mechanisms whereby Keap1 moderates the transcription of genes that are induced by Sendai virus infection in mouse embryo fibroblasts (MEFs). Keap1-/- deletions increased the transcription of virus induced genes independently of Nrf2.

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Proinflammatory cytokine gene transcription must be moderated to avoid the pathological consequences of excess cytokine production. The relationships between virus infection and the mechanisms that moderate cytokine transcription are incompletely understood. We investigated the influence of Keap1 on cytokine gene induction by Sendai virus infection in mouse embryo fibroblasts.

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Background And Purpose: To further the development of new agents for the treatment of adrenocortical carcinoma (ACC), we characterized the molecular and cellular mechanisms of cytotoxicity by the adrenalytic compound ATR-101 (PD132301-02).

Experimental Approach: We compared the effects of ATR-101, PD129337, and ABC transporter inhibitors on cholesterol accumulation and efflux, on cortisol secretion, on ATP levels, and on caspase activation in ACC-derived cell lines. We examined the effects of these compounds in combination with methyl-β-cyclodextrin or exogenous cholesterol to determine the roles of altered cholesterol levels in the effects of these compounds.

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We have developed a procedure that enables visualization of the genomic loci that are bound by complexes formed by a specific combination of chromatin-binding proteins. This procedure is based on imaging bimolecular fluorescence complementation (BiFC) complexes on Drosophila polytene chromosomes. BiFC complexes are formed by the facilitated association of two fluorescent protein fragments that are fused to proteins that interact with, or are in close proximity to, each other.

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Adrenocortical carcinoma (ACC) generally has poor prognosis. Existing treatments provide limited benefit for most patients with locally advanced or metastatic tumors. We investigated the mechanisms for the cytotoxicity, xenograft suppression, and adrenalytic activity of ATR-101 (PD132301-02), a prospective agent for ACC treatment.

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Interactions among transcription factors control their physiological functions by regulating their binding specificities and transcriptional activities. We implement a strategy to visualize directly the genomic loci that are bound by multi-protein complexes in single cells in Drosophila. This method is based on bimolecular fluorescence complementation (BiFC) analysis of protein interactions on polytene chromosomes.

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Embryonic stem (ES) cells express pluripotency-associated genes and repress differentiation-inducible genes. The activities of these genes are coordinately reversed during differentiation. The changes in the transcriptome upon conditional KAP1 knockout in ES cells overlapped with the changes during embryoid body formation.

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Ubiquitin-family peptide conjugation regulates the functions and stabilities of many proteins. Numerous cellular proteins are modified by covalent conjugation of ubiquitin-family peptides to specific lysine residues. These modifications provide a flexible means for regulating the properties of the substrate proteins.

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This multicolor bimolecular fluorescence complementation procedure is designed for the analysis of alternative protein interactions in cultured mammalian cells, but it can be readily adapted to any cell type or aerobically grown organism that can be genetically modified to express the fusion proteins.

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Many proteins can interact with several alternative partners. The multicolor bimolecular fluorescence complementation (BiFC) assay enables simultaneous visualization of multiple protein interactions in the same cell. This assay, introduced here, is based on the fusion of fragments of fluorescent proteins that form spectrally distinct BiFC complexes to different interaction partners.

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Bimolecular fluorescence complementation (BiFC) analysis enables direct visualization of protein interactions and modifications in living cells. It is based on the facilitated association of two nonfluorescent fragments of a fluorescent protein fused to putative interaction partners. The intrinsic fluorescence of the active complex enables detection of protein interactions with high sensitivity, fine spatial resolution, and minimal perturbation of the cells.

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Bimolecular fluorescence complementation (BiFC) analysis enables direct visualization of protein interactions in living cells. It is based on the facilitated association of two nonfluorescent fragments of a fluorescent protein fused to putative interaction partners. The intrinsic fluorescence of the active complex enables detection of protein interactions with high sensitivity, fine spatial resolution, and minimal perturbation of the cells.

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Mammalian Nrf2-Keap1 and the homologous Drosophila CncC-dKeap1 protein complexes regulate both transcriptional responses to xenobiotic compounds as well as native cellular and developmental processes. The relationships between the functions of these proteins in xenobiotic responses and in development were unknown. We investigated the genes regulated by CncC and dKeap1 during development and the signal transduction pathways that modulate their functions.

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ATF2-Jun, IRF3, and HMGI recognize a composite regulatory element within the interferon-β enhancer (IFNb). Cooperative ATF2-Jun-IRF3 complex formation at IFNb has been proposed to require a fixed orientation of ATF2-Jun binding. Our results show that ATF2-Jun heterodimers bound IFNb in both orientations alone and in association with IRF3 and HMGI.

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Voltage-gated potassium (Kv) channels are critical for neuronal excitability and are targeted to specific subcellular compartments to carry out their unique functions. While it is widely believed that Kv channels exist as heteromeric complexes in neurons, direct tests of the hypothesis that specific heteromeric channel populations display divergent spatial and temporal dynamics are limited. Using a bimolecular fluorescence complementation approach, we monitored the assembly and localization of cell surface channel complexes in living cells.

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Cardiac homeostasis is maintained by a balance of growth-promoting and growth-modulating factors. Sustained elevation of calcium signaling can induce cardiac hypertrophy through activation of Nfat family transcription factors. FoxP family transcription factors are known to interact with Nfat proteins and to modulate their transcriptional activities in lymphocytes.

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Polycomb group (PcG) proteins control the epigenetic inheritance of transcription regulatory states during development. Progression from pluripotency to differentiation requires the concurrent activation and repression of different PcG target genes. We found that REST and nine REST-associated proteins copurified with Cbx family PcG proteins from mouse embryonic stem (ES) cells.

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Background Information: Cell fusion is known to underlie key developmental processes in humans and is postulated to contribute to tissue maintenance and even carcinogenesis. The mechanistic details of cell fusion, especially between different cell types, have been difficult to characterize because of the dynamic nature of the process and inadequate means to track fusion products over time. Here we introduce an inducible system for detecting and tracking live cell fusion products in vitro and potentially in vivo.

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Polycomb Group (PcG) proteins are transcription regulatory proteins that control the expression of a variety of genes from early embryogenesis through birth to adulthood. PcG proteins form several complexes that are thought to collaborate to repress gene transcription. Individual PcG proteins have unique characteristics, and mutations in genes encoding different PcG proteins cause distinct phenotypes.

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Investigations of the molecular processes that sustain life must include studies of these processes in their normal cellular environment. The bimolecular fluorescence complementation (BiFC) assay provides an approach for the visualization of protein interactions and modifications in living cells. This assay is based on the facilitated association of complementary fragments of a fluorescent protein that are fused to interaction partners.

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Bimolecular fluorescence complementation (BiFC) analysis enables visualization of the subcellular locations of protein interactions in living cells. Using fragments of different fluorescent proteins, we investigated the temporal resolution and the quantitative accuracy of BiFC analysis. We determined the kinetics of BiFC complex formation in response to the rapamycin-inducible interaction between the FK506 binding protein (FKBP) and the FKBP-rapamycin binding domain (FRB).

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Fos and Jun are components of activator protein-1 (AP-1) and play crucial roles in the regulation of many cellular, developmental, and physiological processes. Caenorhabditis elegans fos-1 has been shown to act in uterine and vulval development. Here, we provide evidence that C.

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Polycomb group proteins are transcriptional repressors recruited to many developmental control genes. The specificity of polycomb group protein targeting is incompletely understood. Subunits of polycomb repressive complexes (PRC) are encoded by multigene families in vertebrates.

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Ubiquitination regulates many cellular functions, including protein localization and degradation. Each function is specified by unique determinants in the conjugate. Ubiquitinated Jun is localized to lysosomes for degradation.

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