Pamela Tuma's Headshot


  • Biology
  • School

  • School of Arts and Sciences
  • Expertise

  • Hepatic Cell Biology in Health and Disease
  • Teaching Interests

    • Biochemistry
    • Membrane Trafficking and Human Disease
    • Signal Transduction and Biomembranes

    Research Interests

    The work in the Tuma lab is divided into two major areas.  The first area examines how specialized human liver functions are reflected in the exquisite architecture of the hepatocyte (the major liver cell type) and the corresponding protein trafficking pathways, and how these pathways are perturbed during tumorigenesis.  The second area examines how hepatocyte structure and function are altered upon chronic alcohol consumption leading to liver damage. 

    Part 1: Hepatocyte protein trafficking in liver health and disease

    Epithelial cells are vital for the success of multicellular organisms. They line all organs providing a selective barrier between the external and internal worlds. The plasma membrane of polarized hepatic cells is physically continuous, but functionally and compositionally divided into two domains: the apical and basolateral. Each domain is characterized by distinct functions that require a specific set of membrane proteins. How is this surface polarity established and maintained? We believe that understanding and defining the mechanisms that regulate polarized protein sorting of newly-synthesized proteins to their respective surface domains will help answer that question. Because epithelial-derived cancer cells either lose or fail to achieve surface polarity, it is important to consider how loss/dysregulation of polarized protein trafficking contributes to malignant transformation. This is of particular interest to us because MAL2 (myelin and lymphocyte protein 2) - a protein that we have been investigating for more than a dozen years - is highly up-regulated in a host of human cancers including renal carcinoma, cholangiocarcinoma, and cancers of the stomach, breast, ovary and pancreas. We currently focus on two MAL2 binding partners, serine/threonine kinase 16 (STK16) and the small molecular weight GTPase, rab17. Our efforts are largely divided into two parts: understanding protein sorting in the polarized hepatocyte and in the “differently-polarized” tumorigenic cell to tease out critical differences in the itineraries and the molecules that regulate these pathways. Our ultimate goal is to uncover potential novel therapeutic strategies for the treatment of cancer.

    Part 2: Alterations in liver structure and function associated with alcoholic liver disease

    Why study alcoholic liver disease? Approximately 75% of all Americans consume alcohol, and 100,000 deaths per year are attributed to alcohol consumption.  Of those deaths, more than 20,000 are caused by liver cirrhosis, the seventh largest cause of death among Americans.  Although alcoholic liver disease is a major biomedical health concern in the United States, little is known about the molecular mechanisms that contribute to the progression of liver injury.  Defining how alcohol consumption changes liver cell structure and function is critical for the development of effective treatments for patients suffering not only from alcoholic liver disease, but also from other liver diseases (e.g., hepatitis, liver cancer) that lead to cirrhosis.  

    Why study alcohol-induced liver damage in WIF-B cells? The liver is the major site of alcohol metabolism, and thus, the most susceptible organ to alcohol-induced injury. In the early stages of the disease, a fatty liver develops which can lead to hepatocyte injury, liver fibrosis, and ultimately to cirrhosis. Although the disease progression is well described in patients, it is not understood why and how this progression occurs. Traditionally, animal models (e.g., rats, primates) have been used to describe physiological responses to alcohol consumption, but these approaches can be problematic. Animals can vary significantly in their responses to alcohol, and it is often difficult and expensive to do animal studies. Thus, many researchers are trying to find alternative strategies to study alcohol-induced liver damage. We have been developing one such alternative strategy: the WIF-B cells. These cells maintain their liver-specific structure and functions in vitro and efficiently metabolize alcohol like intact liver. Also importantly, they exhibit the same cellular alterations as seen in alcohol-exposed livers. We are examining alcohol-induced alterations in polarized protein sorting with respect to alcohol-induced alterations in microtubule modifications and dynamics and how they together contribute to the progression of early stages of alcoholic liver damage. In the end, we hope these studies lead to novel therapeutic strategies. 

    Research Funding

    Dr. Tuma's research is funded by the National Institute of Health.

    Recent Publications

    Groebner, J.L., Girón Bravo, M.M., Rothberg, M.L., Adhikari, R., Tuma, D.J. and P.L. Tuma. 2019. Alcohol-induced microtubule acetylation leads to the accumulation of large, immobile lipid droplets. Am J Physiol Gastrointest Liver Physiol. 317(4):G373-G386.

    Schulze RJ, Schott MB, Casey CA, Tuma PL, McNiven MA. 2019. The cell biology of the hepatocyte: A membrane trafficking machine. J Cell Biol. 218(7):2096-2112.

    Striz, A.C., Stephan, A.P. and P.L. Tuma. 2018. Rab17 regulates apical delivery of hepatic transcytotic vesicles. Molec Biol Cell. 29(23):2887-2897

    López-Coral, A., Striz, A.C. and P.L.Tuma. 2018. A serine/threonine kinase 16-based phospho-proteomics screen identifies WD repeat protein-1 as a regulator of constitutive secretion. Sci Rep. 8:13049.

    Fabian, R, Tyson, C, Tuma, PL, Pegg, I, and A Sarkar. 2018. A horizontal magnetic tweezers and its use for studying single DNA molecules. Micromachines. 9(4), 188.

    Doody, E.E.*, Groebner, J.L.*, Walker, J.R.*, Frizol, B.M., Fernandez, D.J., Tuma, D.J. and P.L. Tuma.  2017. Ethanol metabolism by alcohol dehydrogenase or cytochrome P450 2E1 differentially impair hepatic protein trafficking and growth hormone signaling. Am J Physiol Gastrointest Liver Physiol. 313:G558-G569 *authors with equal contributions

    Striz, A.C. and P.L. Tuma.  2016. GTP-bound and sumoylated rab17 selectively binds the apically-locate d syntaxin 2 in polarized hepatic cells. J. Biol. Chem. 291(18):9721-32. 

    P.L. Tuma. A researcher at an AREA grant-eligible institution. 2016. Cell and Molec. Gastro. and Hepatol. 2:260-262. 

    Groebner, J.L. and P.L. Tuma. 2015. The altered hepatic tubulin code in alcoholic liver disease. Biomolecules. 18; 5(3):2140-59. 

    McAndrew, C., Tyson, C., Zischkau, J., Mehl, P., Tuma, P.L., Pegg, I.L. and A. Sarkar.2015. A Simple Horizontal Magnetic Tweezers for Micromanipulation of Single DNA Molecules and DNA-Protein Complexes. Biotechniques. 60:21-7 

    Tyson, C., McAndrew, C., Tuma, P.L., Pegg, I and A. Sarkar. 2015. An automated non-parametric method for detection of step-like features in biological data sets. Cytometry: Part A. 87: 393–404.

    Coelho, S.G., Valencia, J.C., Lanlan, Y., Smuda, C., Mahn, A., Ludger, K., Miller, S.A., Beer, J.Z., Tuma, P.L., and V.J. Hearing. 2015.  UV exposure modulates hemidesmosome plasticity contributing to long-term pigmentation in human skin. J. Pathology. 236(1):17-29. 

    Weis, G.W., Petersen, C.P., Nam, K.T., Tuma, P.L., Whitehead, R.H. and J.R. Goldenring. 2014. Establishment of novel in vitro mouse chief cell and SPEM cultures identifies MAL2 as a marker of metaplasia in the stomach. Amer. J. Physiol. Gastroint. and Liver Physiol. 15;307:G777-92.  

    Groebner, J.G., Fernandez, D.J, Tuma, D.J., and Tuma, P.L.. 2014. Alcohol-induced defects in hepatic transcytosis may be explained by impaired dynein function. Molec. Cell. Biochem. 397(1-2):223-33. 

    In, J.G., Striz, A.C., Bernad, A.  and  Tuma, P.L..  2014. Serine/threonine kinase 16 and MAL2 regulate constitutive secretion of soluble cargo in hepatic cells. Biochem J. 463(2):201-13.

    In JG, Ihrke G, Tuma PL. 2012. Analysis of polarized membrane traffic in hepatocytes and hepatic cell lines. Curr. Protoc. Cell Biol. Chapter 15: Unit 15.17.

    Shepard BD, Tuma DJ, Tuma PL. 2012. Lysine acetylation induced by chronic ethanol consumption impairs dynamin-mediated clathrin-coated vesicle release. Hepatology. 55:1260-70.

    Ramnarayanan SP, Tuma PL. 2011. MAL, but not MAL2, expression promotes the formation of cholesterol-dependent membrane domains that recruit apical proteins. Biochem. J.439;497-504.

    In, J.G., and P.L. Tuma. 2010. MAL2 selectively regulates polymeric IgA receptor delivery from the golgi to the plasma membrane in WIF-B cells. Traffic 11:1056-66.

    Shepard, B.D., and P.L. Tuma. 2010. Alcohol-induced alterations of the hepatocyte cytoskeleton. World J Gastroenterol. 16:1358-65

    Shepard, B.D, Tuma, D.J., and P.L. Tuma. 2009. Alcohol consumption leads to global protein hyperacetylation. Alcoholism: Clin Exp Res. 34:280-91

    Shepard, B.D., Fernandez, D.J., and P.L. Tuma. 2009. Alcohol consumption impairs hepatic protein trafficking: mechanisms and consequences. Genes Nutr. 5: 129-40

    Fernandez, D.J, McVicker, B.L, Tuma, D.J., and P.L. Tuma. 2009. Ethanol selectively impairs clathrin-mediated internalization in polarized hepatic cells. Biochem. Pharm. 78:648-55

    McVicker, B.L., Tuma, P.L., Kubik, J.L., Kharbanda, K.K., Lee, S.M.L., and D.J. Tuma. 2009.Relationship between oxidative stress and hepatic glutathione levels in ethanol-mediated apoptosis of polarized hepatic cells. World J Gastroenterol. 15:2609-16.

    Shepard, B.D., and P.L. Tuma. 2009. Alcohol-induced protein hyperacetylation: mechanisms and consequences. World J Gastroenterol. 15:1219-1230.

    Shepard, B.D., Joseph, R.A., Kannarkat, G.T., Rutledge, T., Tuma, D.J., and P.L. Tuma. 2008. Ethanol induced alterations in hepatic microtubule dynamics may be explained by impaired function of the microtubule deacetylase, HDAC6. Hepatology. 48:1671-1679.

    Ramnarayanan, S.P., In, J.G., Shepard, B.D., and P.L.Tuma. 2008. Immunoblots. In: Biological Research Methodology - A Handbook. F. Casorta and J.J. Greene, Editors. Taylor and Francis Group, Publishers. Florence, KY (in press).

    In, J.G., Shepard, B.D., Ramnarayanan, S.P., and P.L.Tuma. 2008. Immunoprecipitations. In:Biological Research Methodology - A Handbook. F. Casorta and J.J. Greene, Editors. Taylor and Francis Group, Publishers. Florence, KY (in press).

    Joseph, R. A., Shepard, B.D., Kannarkat, G.T., Rutledge, T., Tuma, D.J., and P.L. Tuma. 2008. Microtubule acetylation and stability may explain alcohol-induced alterations in hepatic protein trafficking. Hepatology. 47:1745-53.

    Ramnarayanan, S.P., Cheng, C.A., Bastaki, M., and P.L. Tuma. 2007. Exogenous MAL selectively reroutes apical delivery in polarized, hepatic WIF-B cells. Molec. Biol. Cell. 18:2707-15.

    McVicker, BL., Tuma, DJ., Kubik, JA., Tuma, PL, and CA Casey. 2006. Ethanol-induced apoptosis in polarized hepatic cells. Alcoholism: Clin Exp Res 30:1906-15

    Kannarkat, G.T., Tuma, D.J., and P.L. Tuma. 2006. Microtubules are more stable and more highly acetylated in ethanol-treated hepatic cell. J. Hepatol. 44:963-970.

    Hanson, L., May, L., Ambudkar, S.V., Tuma, P.L., Keeven, J., Mehl, P., and J. Golin. 2005. The role of hydrogen bond-acceptor groups in the interaction of substrates with Pdr5p, a major yeast drug transporter. Biochemistry 44:9703-9713.

    Shaffert, C.S., Todero, S.L., McVicker, B.L., Tuma, P.L., Sorrell, M.F. and D.J. Tuma. 2004. WIF-B cells as a model for studying alcohol-induced hepatocyte injury. Biochem. Pharmacol. 67:2167-2174.

    Graf, G.A., Yu, L., Li, W.P., Gerard, R., Tuma, P.L., Cohen, J. and H.H. Hobbs. 2003. ABCG5 and ABCG8 are obligate heterodimers for protein trafficking and biliary cholesterol excretion. J. Biol. Chem. 278:48275-48282.

    Nyasae, L.K., Hubbard, A.L. and P.L. Tuma. 2003. Transcytotic efflux from early endosomes is dependent on cholesterol and glycosphingolipids in polarized hepatocytes. Molec. Biol. Cell14:2689-2705.

    Tuma, P.L. and A.L. Hubbard. 2003. Transcytosis: Crossing cellular barriers. Physiological Reviews 83:871-932.

    Tuma, P.L., Nyasae, L.K., and A.L. Hubbard. 2002. Nonpolarized cells selectively sort apical proteins from the cell surface to a novel compartment, but lack apical retention mechanisms. Molec. Biol. Cell 13:3400-3415

    Tuma, P.L., Nyasae, L.K., Backer, J.M., and A.L. Hubbard. 2001. Vps34p differentially regulates endocytosis from the apical and basolateral domains in polarized hepatic cells. J. Cell Biol. 154: 1197-1208.

    Tuma, P.L., and A.L. Hubbard. 2001. The hepatocyte surface: dynamic polarity. In: Liver Biology and Pathobiology. I.M. Arias, J.L. Boyer, F.V Chisari, N. Faust, D. Schachter and D.A. Shafritz, editors. Raven Press, New York, NY. 97-117.

    Tuma, P.L., and A.L. Hubbard. 1999. Isolation of rat hepatocyte plasma membrane sheets and plasma membrane domains. Supplement. In: Current Protocols in Cell Biology. J.S. Bonifacino, M. Dasso, J. Lippincott Schwartz, J.B. Harford and K.M. Yamada, editors. John Wiley and Sons, New York, NY. 3.2.1-16.

    Lapierre, L.A., Tuma. P.L., Navarre, J., Goldenring, J.R., and J.M. Anderson. 1999. VAP-33 localizes to both an intracellular vesicle population and with occludin at the tight junction. J. Cell Sci. 112: 3723-3732.

    Tuma, P.L., Finnegan, C.M., Yi, J.-H., and A.L. Hubbard. 1999. Evidence for apical endocytosis in hepatic cells: resident apical plasma membrane proteins redistribute into lysosomally-derived vacuoles in the presence of phosphoinositide 3-kinase inhibitors. J. Cell Biol. 145:1089-1102.

    *Fujita, H., *Tuma, P.L., Finnegan, C.M., Locco, L. and A.L. Hubbard. 1998. Endogenous syntaxins 2, 3 and 4 exhibit distinct but overlapping patterns of expression at the hepatocyte plasma membrane. Biochem. J. 329:527-538. *contributed equally

    Tuma, P.L., and C.A. Collins. 1995. Dynamin forms polymeric complexes in the presence of lipid vesicles: characterization of chemically cross-linked dynamin molecules. J. Biol. Chem. 270:26707-26714.

    Tuma, P.L., and C.A. Collins. 1994. Activation of dynamin GTPase is a result of positive cooperativity. J. Biol. Chem. 269:30842-30847.

    Tuma, P.L., Stachniak, M.C., and C.A. Collins. 1993. Activation of dynamin GTPase by acidic phospholipids and endogenous rat brain vesicles. J. Biol. Chem. 268:17240-17246.