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UC Davis Nutrition Department - Haj Lab


Fawaz HajWelcome to the website for the laboratory of Dr. Fawaz Haj in the Department of Nutrition at the University of California, Davis.

Dr. Haj´s laboratory studies the role of tyrosine phosphorylation and dephosphorylation in cell signaling and disease. Research focuses on the function of protein-tyrosine phosphatases (PTPs) in regulating insulin signaling and how deregulation of these pathways leads to diseases such as obesity and type 2 diabetes. This is achieved through the combined use of biochemical, cellular and knockout mouse studies. Collectively, these approaches will enable the dissection of metabolic regulation at the cellular and organism levels.


  • B.Sc., Biology, American University of Beirut
  • M.Sc., Biomedical Sciences, Bradford University
  • D.Phil., Physiology, Oxford University

Post Graduate Training

  • Postdoctoral Fellow, Harvard Medical School
  • Instructor in Medicine, Harvard Medical School
  • Visiting Scientist, European Molecular Biology Laboratory

Academic Appointments

  • Assistant Professor, Nutrition Department, University of California Davis, 2007-2011
  • Associate Professor, Nutrition Department, University of California Davis, 2011-present
  • Associate Professor, Internal Medicine Department, University of California Davis, 2012-present

Administrative Appointments

  • Director, Meyer Hall Animal Facility, University of California Davis, 2008-present
  • Co-Director, Metabolism and Endocrinology Core, National Mouse Metabolic Phenotyping Center, University of California Davis, 2011-present

Awards and Honors

  • Oxford University, Oxford Overseas Bursaries, 1997
  • Oxford University, Overseas Research Scholarship, 1997
  • Harvard University, Certificate of Excellence in Research, 2001
  • University of California Davis, Hellman Fellow, 2008

Oral presentations (last 3 years)


  • Division of Endocrinology, Diabetes and Metabolism, University of Miami, Miami, Florida, USA
  • School of Medicine, University of Miami, Miami, Florida, USA
  • Pre-Obesity Society Symposium, Orlando, Florida, USA
  • 9th International Conference on Protein Phosphatases, Tokyo, Japan
  • Department of Microbiology, Yokohama City University, Yokohama, Japan
  • EMBO conference on protein phosphatases, Vienna, Austria
  • Department of Biology, University of Copenhagen, Copenhagen, Denmark
  • Frontiers of Science, Engineering and Medicine Symposium, Kuwait Institute for Scientific Research, Kuwait City, Kuwait
  • Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
  • Taiwan Society for Biochemistry and Molecular Biology, Taipei, Taiwan
  • Department of Biological Sciences, National University of Singapore, Singapore
  • Duke-National University of Singapore Graduate Medical School, Singapore


  • Comprehensive Cancer Center, University of California Davis, Sacramento, CA, USA
  • Department of Orthopedics, University of California Davis, Sacramento, CA, USA
  • Protein Phosphatases Conference, Silvertree, CO, USA
  • Department of Nutritional Biology and Toxicology, University of California Berkeley, CA, USA
  • Phosphatases in human disease conference, Melbourne, Australia
  • Garvan Institute, Sydney, Australia
  • International conference on obesity and weight management, Philadelphia, PA, USA


  • Biotechnology Research Institute, University of San Martin, Buenos Aires, Argentina
  • Division of Endocrinology, Diabetes and Metabolism, University of California Davis, Sacramento, CA
  • 10th International Conference on Protein Phosphatases and Diseases, Tokyo, Japan
  • Brain-Liver Interface Medicine Research Center, Kanazawa University, Kanazawa, Japan
  • Nutrition, Oxygen Biology and Medicine Conference, Paris, France           
  • Department of Molecular Cell Biology, University of Leuven, Belgium
  • VI International Conference on Polyphenols and Health, Buenos Aires, Argentina
  • Institute of Biomedical Investigation Alberto Sols, Madrid, Spain
  • Department of Physiology, University of Valencia, Valencia, Spain

Publications (last 3 years)


  • Ahmed Bettaieb, Siming Liu, Yannan Xi, Naoto Nagata, Kosuke Matsuo, Izumi Matsuo, Samah Chahed, Jesse Bakke, Heike Keilhack, Tony Tiganis and Fawaz Haj. Differential regulation of endoplasmic reticulum stress by protein tyrosine phosphatase 1B and T cell protein tyrosine phosphatase. Journal of Biological Chemistry, Mar 18;286(11):9225-35.  [PubMed]
  • Kosuke Matsuo, Ahmed Bettaieb, Naoto Nagata, Izumi Matsuo and Fawaz Haj. Regulation of brown fat adipogenesis by protein tyrosine phosphatase 1B. PLoS One, Jan 31;6(1):e16446. [PubMed]
  • Ahmed Bettaieb, Kosuke Matsuo, Izumi Matsuo and Fawaz Haj. Adipose-specific Src Homology Phosphatase 2 deficiency does not significantly alter systemic glucose homeostasis. Metabolism, Aug;60(8):1193-201.  [PubMed]
  • Ayala Luria, Ahmed Bettaieb, Yannan Xi, Guang-Jong Shieh, Hsin-Chen Liu, Hiromi Inoue, Hsing-Ju Tsai, John Imig, Fawaz Haj and Bruce Hammock. Soluble epoxide hydrolase deficiency alters pancreatic islet size and improves glucose homeostasis in a model of insulin resistance induced by high fat diet. Proceedings of the National Academy of Sciences, May 31;108(22):9038-43. [PubMed]
  • Bethany Cummings, Ahmed Bettaieb, James Graham, Kimber Stanhope, Riva Dill, Gregory Morton, Fawaz Haj and Peter Havel. Subcutaneous administration of leptin normalizes fasting plasma glucose in obese type 2 diabetes UCD-T2DM rats. Proceedings of the National Academy of Sciences, August 30; 108(35):14670-5.  [PubMed]


  • Marcela Vazquez Prieto, Ahmed Bettaieb, Fawaz Haj, Cesar Fraga, Patricia Oteiza. (-)-Epicatechin prevents TNFα-induced activation of signaling cascades leading to inflammation and insulin resistance in 3T3 adipocytes. Archives of Biochemistry and Biophysics, Nov 15; 527(2):113-8. [PubMed]
  • Ahmed Bettaieb, Kosuke Matsuo, Shuo Wang, Izumi Matsuo, Ramzi Melhem, Antonis Koromilas and Fawaz Haj. Protein tyrosine phosphatase 1B deficiency potentiates PERK/eIF2α signaling in brown adipocytes. PLoS One, 7(4):e34412. [PubMed]
  • Fawaz Haj, Ola Sabet, Ali Kinkhabwala, Sabine Wimmer-Kleikamp, Vassilis Roukos,Hong-Mei Han, Markus Grabenbauer, Martin Bierbaum, Claude Antony, Benjamin Neel, and Philippe Bastiaens. Regulation of signaling at regions of cell-cell contact by endoplasmic reticulum-bound protein-tyrosine phosphatase 1B. PLoS One, 7(5):e36633. [PubMed]
  • Naoto Nagata, Kosuke Matsuo, Ahmed Bettaieb, Jesse Bakke, Izumi Matsuo, James Graham, Yannan Xi, Siming Liu, Alexey Tomilov, Natalia Tomilova, Susan Gray, Dae Young Jung, Jon Ramsey, Jason Kim, Gino Cortopassi, Peter Havel and Fawaz Haj. Hepatic Src Homology Phosphatase 2 regulates energy balance in mice. Endocrinology, Jul;153(7):3158-69. [PubMed]
  • Bethany Cummings, Ahmed Bettaieb, James Graham, Kimber Stanhope, Mark Kowala, Fawaz Haj, Michael Chouinard, and Peter Havel. Vertical sleeve gastrectomy improves glucose and lipid metabolism and delays diabetes onset in UCD-T2DM rats. Endocrinology, Aug;153(8):3620-32. [PubMed]
  • Bora Inceoglu, Karen Wagner, Jun Yang, Ahmed Bettaieb, Nils Schebb, Fawaz Haj, Bruce Hammock. Augmentation of epoxygenated fatty acid levels rapidly reduce pain-related behavior without significantly altering acute glucose metabolism in a rat model of type I diabetes. Proceedings of the National Academy of Sciences, Jul 10;109(28):11390-5. [PubMed]


  • Bakke J, Bettaieb A, Nagata N, Matsuo K, Haj FG. Regulation of the SNARE-interacting protein Munc18c tyrosine phosphorylation in adipocytes by protein-tyrosine phosphatase 1B. Cell Commun Signal. 2013 Aug 12;11:57.  [PubMed]
  • Bettaieb A, Bakke J, Nagata N, Matsuo K, Xi Y, Liu S, AbouBechara D, Melhem R, Stanhope K, Cummings B, Graham J, Bremer A, Zhang S, Lyssiotis CA, Zhang ZY, Cantley LC, Havel PJ, Haj FG. Protein tyrosine phosphatase 1B regulates pyruvate kinase M2 tyrosine phosphorylation. J Biol Chem. 2013 Jun 14;288(24):17360-71. [PubMed]
  • Bettaieb A, Nagata N, AbouBechara D, Chahed S, Morisseau C, Hammock BD, Haj FG. Soluble epoxide hydrolase deficiency or inhibition attenuates diet-induced endoplasmic reticulum stress in liver and adipose tissue. J Biol Chem. 2013 May 17;288(20):14189-99. [PubMed]
  • Lackey DE, Lynch CJ, Olson KC, Mostaedi R, Ali M, Smith WH, Karpe F, Humphreys S, Bedinger DH, Dunn TN, Thomas AP, Oort PJ, Kieffer DA, Amin R, Bettaieb A, Haj FG, Permana P, Anthony TG, Adams SH.Regulation of adipose branched-chain amino acid catabolism enzyme expression and cross-adipose amino acid flux in human obesity. Am J Physiol Endocrinol Metab. 2013 Jun 1;304(11):E1175-87. [PubMed]
  • Cummings BP, Bettaieb A, Graham JL, Kim J, Ma F, Shibata N, Stanhope KL, Giulivi C, Hansen F, Jelsing J, Vrang N, Kowala M, Chouinard ML, Haj FG, Havel PJ. Bile-acid-mediated decrease in endoplasmic reticulum stress: a potential contributor to the metabolic benefits of ileal interposition surgery in UCD-T2DM rats. Dis Model Mech. 2013 Mar;6(2):443-56. [PubMed]