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- Björkman, Lena, 1965, et al.
(author)
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The Neutrophil Response Induced by an Agonist for Free Fatty Acid Receptor 2 (GPR43) Is Primed by Tumor Necrosis Factor Alpha and by Receptor Uncoupling from the Cytoskeleton but Attenuated by Tissue Recruitment
- 2016
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In: Molecular and Cellular Biology. - : Informa UK Limited. - 0270-7306 .- 1098-5549. ; 36:20, s. 2583-2595
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Journal article (peer-reviewed)abstract
- Ligands with improved potency and selectivity for free fatty acid receptor 2 (FFA2R) have become available, and we here characterize the neutrophil responses induced by one such agonist (Cmp1) and one antagonist (CATPB). Cmp1 triggered an increase in the cytosolic concentration of Ca2+, and the neutrophils were then desensitized to Cmp1 and to acetate, a naturally occurring FFA2R agonist. The antagonist CATPB selectively inhibited responses induced by Cmp1 or acetate. The activated FFA2R induced superoxide anion secretion at a low level in naive blood neutrophils. This response was largely increased by tumor necrosis factor alpha (TNF-alpha) in a process associated with a recruitment of easily mobilizable granules, but neutrophils recruited to an aseptic inflammation in vivo were nonresponding. Superoxide production induced by Cmp1 was increased in latrunculin A-treated neutrophils, but no reactivation of desensitized FFA2R was induced by this drug, suggesting that the cytoskeleton is not directly involved in terminating the response. The functional and regulatory differences between the receptors that recognize short-chain fatty acids and formylated peptides, respectively, imply different roles of these receptors in the orchestration of inflammation and confirm the usefulness of a selective FFA2R agonist and antagonist as tools for the exploration of the precise role of the FFA2R.
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3. |
- Chaudhari, Aditi, et al.
(author)
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p110alpha hot spot mutations E545K and H1047R exert metabolic reprogramming independently of p110alpha kinase activity : Kinase-independent signaling of p110 alpha mutants
- 2015
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In: Molecular and Cellular Biology. - 0270-7306 .- 1098-5549. ; 35:19, s. 3258-3273
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Journal article (peer-reviewed)abstract
- The phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) catalytic subunit p110α is the most frequently mutated kinase in human cancer, and the hot spot mutations E542K, E545K, and H1047R are the most common mutations in p110α. Very little is known about the metabolic consequences of the hot spot mutations of p110α in vivo. In this study, we used adenoviral gene transfer in mice to investigate the effects of the E545K and H1047R mutations on hepatic and whole-body glucose metabolism. We show that hepatic expression of these hot spot mutations results in rapid hepatic steatosis, paradoxically accompanied by increased glucose tolerance, and marked glycogen accumulation. In contrast, wild-type p110α expression does not lead to hepatic accumulation of lipids or glycogen despite similar degrees of upregulated glycolysis and expression of lipogenic genes. The reprogrammed metabolism of the E545K and H1047R p110α mutants was surprisingly not dependent on altered p110α lipid kinase activity.
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4. |
- Chaudhari, Aditi, et al.
(author)
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p110α hot spot mutations E545K and H1047R exert metabolic reprogramming independently of p110α kinase activity
- 2015
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In: Molecular and Cellular Biology. - : American Society for Microbiology. - 0270-7306 .- 1098-5549. ; 35:19, s. 3258-3273
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Journal article (peer-reviewed)abstract
- The phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) catalytic subunit p110α is the most frequently mutated kinase in human cancer, and the hot spot mutations E542K, E545K, and H1047R are the most common mutations in p110α. Very little is known about the metabolic consequences of the hot spot mutations of p110α in vivo. In this study, we used adenoviral gene transfer in mice to investigate the effects of the E545K and H1047R mutations on hepatic and whole-body glucose metabolism. We show that hepatic expression of these hot spot mutations results in rapid hepatic steatosis, paradoxically accompanied by increased glucose tolerance, and marked glycogen accumulation. In contrast, wild-type p110α expression does not lead to hepatic accumulation of lipids or glycogen despite similar degrees of upregulated glycolysis and expression of lipogenic genes. The reprogrammed metabolism of the E545K and H1047R p110α mutants was surprisingly not dependent on altered p110α lipid kinase activity.
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6. |
- Fleenor, Courtney J., et al.
(author)
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Zinc Finger Protein 521 Regulates Early Hematopoiesis through Cell-Extrinsic Mechanisms in the Bone Marrow Microenvironment
- 2018
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In: Molecular and Cellular Biology. - : AMER SOC MICROBIOLOGY. - 0270-7306 .- 1098-5549. ; 38:17
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Journal article (peer-reviewed)abstract
- Zinc finger protein 521 (ZFP521), a DNA-binding protein containing 30 Kruppel-like zinc fingers, has been implicated in the differentiation of multiple cell types, including hematopoietic stem and progenitor cells (HSPC) and B lymphocytes. Here, we report a novel role for ZFP521 in regulating the earliest stages of hematopoiesis and lymphoid cell development via a cell-extrinsic mechanism. Mice with inactivated Zfp521 genes (Zfp521(-/-)) possess reduced frequencies and numbers of hematopoietic stem and progenitor cells, common lymphoid progenitors, and B and T cell precursors. Notably, ZFP521 deficiency changes bone marrow microenvironment cytokine levels and gene expression within resident HSPC, consistent with a skewing of hematopoiesis away from lymphopoiesis. These results advance our understanding of ZFP521s role in normal hematopoiesis, justifying further research to assess its potential as a target for cancer therapies.
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7. |
- Jacobson, Therese, et al.
(author)
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Cadmium Causes Misfolding and Aggregation of Cytosolic Proteins in Yeast.
- 2017
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In: Molecular and Cellular Biology. - 1098-5549. ; 37:17
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Journal article (peer-reviewed)abstract
- Cadmium is a highly poisonous metal and is classified as a human carcinogen. While its toxicity is undisputed, the underlying in vivo molecular mechanisms are not fully understood. Here, we demonstrate that cadmium induces aggregation of cytosolic proteins in living Saccharomyces cerevisiae cells. Cadmium primarily targets proteins in the process of synthesis or folding, probably by interacting with exposed thiol groups in not-yet-folded proteins. On the basis of in vitro and in vivo data, we show that cadmium-aggregated proteins form seeds that increase the misfolding of other proteins. Cells that cannot efficiently protect the proteome from cadmium-induced aggregation or clear the cytosol of protein aggregates are sensitized to cadmium. Thus, protein aggregation may contribute to cadmium toxicity. This is the first report on how cadmium causes misfolding and aggregation of cytosolic proteins in vivo The proposed mechanism might explain not only the molecular basis of the toxic effects of cadmium but also the suggested role of this poisonous metal in the pathogenesis of certain protein-folding disorders.
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8. |
- Jacobson, Therese, et al.
(author)
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Cadmium Causes Misfolding and Aggregation of Cytosolic Proteins in Yeast
- 2017
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In: Molecular and Cellular Biology. - : Informa UK Limited. - 0270-7306 .- 1098-5549. ; 37:17
-
Journal article (peer-reviewed)abstract
- Cadmium is a highly poisonous metal and is classified as a human carcinogen. While its toxicity is undisputed, the underlying in vivo molecular mechanisms are not fully understood. Here, we demonstrate that cadmium induces aggregation of cytosolic proteins in living Saccharomyces cerevisiae cells. Cadmium primarily targets proteins in the process of synthesis or folding, probably by interacting with exposed thiol groups in not-yet-folded proteins. On the basis of in vitro and in vivo data, we show that cadmium-aggregated proteins form seeds that increase the misfolding of other proteins. Cells that cannot efficiently protect the proteome from cadmium-induced aggregation or clear the cytosol of protein aggregates are sensitized to cadmium. Thus, protein aggregation may contribute to cadmium toxicity. This is the first report on how cadmium causes misfolding and aggregation of cytosolic proteins in vivo. The proposed mechanism might explain not only the molecular basis of the toxic effects of cadmium but also the suggested role of this poisonous metal in the pathogenesis of certain protein-folding disorders.
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9. |
- Kaimal, Jayasankar Mohanakrishnan, et al.
(author)
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Coordinated Hsp110 and Hsp104 Activities Power Protein Disaggregation in Saccharomyces cerevisiae
- 2017
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In: Molecular and Cellular Biology. - 0270-7306 .- 1098-5549. ; 37:11
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Journal article (peer-reviewed)abstract
- Protein aggregation is intimately associated with cellular stress and is accelerated during aging, disease, and cellular dysfunction. Yeast cells rely on the ATP-consuming chaperone Hsp104 to disaggregate proteins together with Hsp70. Hsp110s are ancient and abundant chaperones that form complexes with Hsp70. Here we provide in vivo data showing that the Saccharomyces cerevisiae Hsp110s Sse1 and Sse2 are essential for Hsp104-dependent protein disaggregation. Following heat shock, complexes of Hsp110 and Hsp70 are recruited to protein aggregates and function together with Hsp104 in the disaggregation process. In the absence of Hsp110, targeting of Hsp70 and Hsp104 to the aggregates is impaired, and the residual Hsp104 that still reaches the aggregates fails to disaggregate. Thus, coordinated activities of both Hsp104 and Hsp110 are required to reactivate aggregated proteins. These findings have important implications for the understanding of how eukaryotic cells manage misfolded and amyloid proteins.
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10. |
- Kumar, Nallani Vijay, et al.
(author)
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Arsenic Directly Binds to and Activates the Yeast AP-1-Like Transcription Factor Yap8.
- 2016
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In: Molecular and cellular biology. - 1098-5549. ; 36:6, s. 913-22
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Journal article (peer-reviewed)abstract
- The AP-1-like transcription factor Yap8 is critical for arsenic tolerance in the yeast Saccharomyces cerevisiae. However, the mechanism by which Yap8 senses the presence of arsenic and activates transcription of detoxification genes is unknown. Here we demonstrate that Yap8 directly binds to trivalent arsenite [As(III)] in vitro and in vivo and that approximately one As(III) molecule is bound per molecule of Yap8. As(III) is coordinated by three sulfur atoms in purified Yap8, and our genetic and biochemical data identify the cysteine residues that form the binding site as Cys132, Cys137, and Cys274. As(III) binding by Yap8 does not require an additional yeast protein, and Yap8 is regulated neither at the level of localization nor at the level of DNA binding. Instead, our data are consistent with a model in which a DNA-bound form of Yap8 acts directly as an As(III) sensor. Binding of As(III) to Yap8 triggers a conformational change that in turn brings about a transcriptional response. Thus, As(III) binding to Yap8 acts as a molecular switch that converts inactive Yap8 into an active transcriptional regulator. This is the first report to demonstrate how a eukaryotic protein couples arsenic sensing to transcriptional activation.
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