title: Pyruvate dehydrogenase has a major role in mast cell function, and its activity is regulated by mitochondrial microphthalmia transcription factor.
abstract: BACKGROUND
  We have recently observed that oxidative phosphorylation-mediated ATP production is essential for mast cell function. Pyruvate dehydrogenase (PDH) is the main regulator of the Krebs cycle and is located upstream of the electron transport chain. However, the role of PDH in mast cell function has not been described. Microphthalmia transcription factor (MITF) regulates the development, number, and function of mast cells. Localization of MITF to the mitochondria and its interaction with mitochondrial proteins has not been explored.
  
  
  OBJECTIVE
  We sought to explore the role played by PDH in mast cell exocytosis and to determine whether MITF is localized in the mitochondria and involved in regulation of PDH activity.
  
  
  METHODS
  Experiments were performed in vitro by using human and mouse mast cells, as well as rat basophil leukemia cells, and in vivo in mice. The effect of PDH inhibition on mast cell function was examined. PDH interaction with MITF was measured before and after immunologic activation. Furthermore, mitochondrial localization of MITF and its effect on PDH activity were determined.
  
  
  RESULTS
  PDH is essential for immunologically mediated degranulation of mast cells. After activation, PDH is serine dephosphorylated. In addition, for the first time, we show that MITF is partially located in the mitochondria and interacts with PDH. This interaction is dependent on the phosphorylation state of PDH. Furthermore, mitochondrial MITF regulates PDH activity.
  
  
  CONCLUSIONS
  The association of mitochondrial MITF with PDH emerges as an important regulator of mast cell function. Our findings indicate that PDH could arise as a new target for the manipulation of allergic diseases.
authors.affiliation: Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.
authors.forename: Israa
authors.initials: I
authors.lastname: Sharkia
authors.affiliation: Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.
authors.forename: Tal
authors.initials: T
authors.lastname: Hadad Erlich
authors.affiliation: Pharmacology and Experimental Therapeutics Unit, School of Pharmacy, Institute for Drug Research, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.
authors.forename: Nadine
authors.initials: N
authors.lastname: Landolina
authors.affiliation: Institute of Pulmonary Medicine, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.
authors.forename: Miri
authors.initials: M
authors.lastname: Assayag
authors.affiliation: Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.
authors.forename: Alex
authors.initials: A
authors.lastname: Motzik
authors.affiliation: Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.
authors.forename: Inbal
authors.initials: I
authors.lastname: Rachmin
authors.affiliation: Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.
authors.forename: Gillian
authors.initials: G
authors.lastname: Kay
authors.affiliation: Flow Cytometry Unit, Biological Services Department, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Ziv
authors.initials: Z
authors.lastname: Porat
authors.affiliation: Department of Nuclear Medicine, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.
authors.forename: Sagi
authors.initials: S
authors.lastname: Tshori
authors.affiliation: Institute of Pulmonary Medicine, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.
authors.forename: Neville
authors.initials: N
authors.lastname: Berkman
authors.affiliation: Pharmacology and Experimental Therapeutics Unit, School of Pharmacy, Institute for Drug Research, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.
authors.forename: Francesca
authors.initials: F
authors.lastname: Levi-Schaffer
authors.affiliation: Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel. Electronic address: ehudr@ekmd.huji.ac.il.
authors.forename: Ehud
authors.initials: E
authors.lastname: Razin
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000485:Allergens / Q000276:immunology; D000818:Animals; D001249:Asthma / Q000276:immunology; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D002452:Cell Count; D015550:Cell Degranulation; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D005089:Exocytosis; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D007658:Ketone Oxidoreductases / Q000276:immunology*; D008297:Male; D008407:Mast Cells / Q000276:immunology* / Q000378:metabolism / Q000502:physiology; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D051739:Microphthalmia-Associated Transcription Factor / Q000235:genetics / Q000276:immunology*; D008928:Mitochondria / Q000276:immunology / Q000378:metabolism; D010047:Ovalbumin / Q000276:immunology; D051381:Rats
chemical_list: D000485:Allergens; D051739:Microphthalmia-Associated Transcription Factor; D000255:Adenosine Triphosphate; D010047:Ovalbumin; D007658:Ketone Oxidoreductases; C053164:pyruvate dehydrogenase (NADP+)
keywords: Allergy; asthma; cytokines; degranulation; mast cells; microphthalmia transcription factor; mitochondria; pyruvate dehydrogenase