• Ph.D., Louisiana State University, Baton Rouge, LA, 1997, Biochemistry
  • B.S.N., University of Alabama at Birmingham, Birmingham, AL, 1977, Nursing

Research Interests

Dr. Floyd has a general interest in protein turnover mediated by the ubiquitin-proteasome system. In particular, her laboratory is interested in understanding how the ubiquitin-proteasome pathway affects adipose tissue biology. Research in the laboratory is currently focused on how ubiquitin and ubiquitin-like modifications regulate the activity of the peroxisome proliferator-activated receptor gamma (PPARgamma), a nuclear hormone receptor required for the formation and maintenance of adipocytes. Our studies show that the ubiquitin ligase Siah2 selectively regulates PPARgamma activity in adipose tissue while also acting to control obesity-related adipose tissue inflammation, the balance between adipose tissue expansion via hyperplasia or hypertrophy and the link between adipocyte hypertrophy and obesity-induced insulin resistance.

Another area of interest in the laboratory is the impact of botanical supplementation on insulin sensitivity. These studies explore the effects of extracts from Russian Tarragon and Bitter Melon, plants with a long history of ameliorating the symptoms of type 2 diabetes. The studies currently focus on identifying the bioactive components of the botanical extracts that enhance insulin signaling in skeletal muscle and improve glucose metabolism.

Department(s) : John S. McIlhenny Botanical Research Laboraotry and Ubiquitin Biology Laboratory

Selected Publications

  1. Dang, T.N., Taylor, J.L., Kilroy, G., Yu, Y., Burk, D.H., Floyd, Z.E. (2020) Siah2 is expressed in adipocyte precursor cells and interacts with Ebf1 and Zfp521 to promote adipogenesis. Obesity. November, Online ahead of print.
  2. Yu, Y., Simmler, C., Kuhn, P., Poulev, A., Raskin, I., Cefalu, W. T., Ribnicky, D., Floyd, Z.E., Pauli, G.F. (2019) The DESIGNER approach helps decipher the hypoglycemic bioactive principles of Artemisia dracunculus (Russian Tarragon). Journal of Natural Products. December 27; 82 (12): 3321-3329. PMCID: PMC7076913
  3. Ghosh, S., Taylor, J.L., Mendoza, T.M., Dang, T., Burk, D.H., Yu, Y., Kilroy, G., Floyd, Z.E. (2019) Siah2 exerts sex-dependent effects on metabolic and inflammatory remodeling in adipose tissue. BMC Biology of Sex Differences. April 15; 10(1):19. PMCID: PMC6466809
  4. Fuller SE, Yu Y, Mendoza TM, Ribnicky DM, Cefalu WT, Floyd ZE. Potential adverse effects of botanical supplementation in high fat-fed female mice. BMC Biology of Sex Differences. 2018; Sept 12;9 (1):41. PMCID: PMC30208938
  5. Xu B, Allard C, Alvarez-Mercado AI, Kim JH, Hewitt SC, Urano R, Korach KS, Levin ER, Arvan P, Floyd, ZE, Mauvais-Jarvis F. Estrogens promote misfolded proinsulin degradation to protect insulin production and delay diabetes. 2018; Cell Reports. July 3; 24:181-196. PMCID: PMC6092934
  6. Kilroy G, Burk DH, Floyd, ZE. Siah2 mediates early events in commitment to an adipogenic pathway. Journal of Biological Chemistry. 2016; Dec 30; 291(53): 27289-27297. PMCID PMC5207155
  7. Kilroy G, Carter LE, Newman S, Burk DH, Manuel J, Moller A, Bowtell DD, Mynatt RL, Ghosh S, Floyd ZE. The ubiquitin ligase Siah2 regulates obesity-induced adipose tissue inflammation. Obesity 2015; 23: 2223-2232. PMCID: PMC4633373
  8. Kilroy SG, Kirk-Ballard H, Carter LE, Floyd ZE. The ubiquitin ligase Siah2 regulates PPARgamma activity in adipocytes. Endocrinology 2012; 153 (3): 1206-1218. PMCID: PMC3281538.
  9. Floyd ZE and Stephens JM. Controlling a master switch of adipocyte development and insulin sensitivity: Covalent modification of PPARgamma. Biochem Biophys Acta 2012; 1822: 1090-1095. PMCID: PMC3355475
  10. Kilroy SG, Burk DH, Floyd ZE. High efficiency siRNA transfection of adipocytes using “reverse transfection”. PLoS One 2009; 4(9) e6940. PMCID: PMC2736387
  11. Kilroy SG, Zhang X, Floyd ZE. PPARgamma AF-2 domain functions as a component of a ubiquitin-dependent degradation signal. Obesity 2009; (4): 665-73. PMCID: PMC2585986
  12. Floyd ZE, Stephens JM. Control of peroxisome proliferator-activated receptor gamma2 stability and activity by SUMOylation. Obes Res. 2004; Jun;12(6):921-8.