Photo of Caroline Enns, Ph.D

Caroline Enns Ph.D

  • (503) 494-5845
    • Professor of Cell, Developmental and Cancer Biology School of Medicine
    • Cancer Biology Graduate Program School of Medicine
    • Cell and Developmental Biology Graduate Program School of Medicine
    • Program in Molecular and Cellular Biosciences School of Medicine

The cell is a highly organized and dynamic structure. Most proteins are found exclusively in one compartment of the cell and are only transported to other locations as a result of intra- or extra-cellular signaling pathways. For the most part, proteins are synthesized in the cytoplasm and targeted either co- or post-translationally to their particular destination. Recently, an increasing number of human diseases have been attributed to mutations which result in the mistargeting of essential proteins. The signals responsible for the targeting membrane proteins in the biosynthetic and endocytic pathways are of particular interest to my laboratory. In addition to studying the basic cell biology of protein trafficking within the cell, we have begun to examine the trafficking and function of the protein implicated in hemochromatosis, the most common hereditary disease of people of European ancestry. Malfunctioning of this protein results in the abnormal accumulation of iron in the body. Iron uptake into the body is highly regulated. Although it is essential for life, too much iron is toxic and results in heart failure, adult onset diabetes, arthritis, and cirrhosis of the liver. We are examining the intracellular trafficking of this protein and how it participates in the control of iron uptake and egress.

Areas of interest

  • cell biology protein trafficking hereditary hemochromatosis cellular basis of human disease structure function of membrane proteins cancer


  • Ph.D., University of Oregon 1976


  • "Diferric transferrin regulates transferrin receptor 2 protein stability" Blood December 15 2004
  • "Iron homeostasis" Journal of Biological Chemistry January 9 2009
  • "Increased Iron Loading Induces Bmp6 Expression in the Non-Parenchymal Cells of the Liver Independent of the BMP-Signaling Pathway" PLoS One April 2 2013
  • "Molecular mechanisms of normal iron homeostasis." Hematology / the Education Program of the American Society of Hematology. American Society of Hematology. Education Program  2009
  • "A rapid redistribution of the transferrin receptor to the cell surface of HL-60 cells and K562 cells upon treatment with dimethyl sulfoxide due to slowing of endocytosis" Archives of Biochemistry and Biophysics  1990
  • "Interaction of the Hereditary Hemochromatosis Protein HFE with Transferrin Receptor 2 Is Required for Transferrin-Induced Hepcidin Expression" Cell Metabolism March 4 2009
  • "Stoichiometries of transferrin receptors 1 and 2 in human liver" Blood Cells, Molecules, and Diseases January 2010
  • "Comparison of the interactions of transferrin receptor and transferrin receptor 2 with transferrin and the hereditary hemochromatosis protein HFE" Journal of Biological Chemistry December 8 2000
  • "Suppression of hepatic hepcidin expression in response to acute iron deprivation is associated with an increase of matriptase-2 protein" Blood February 3 2011
  • "Characterization of proteins that associate with an unglycosylated form of the transferrin receptor in A431 cells" Journal of Biological Chemistry  1988
  • "Human transferrin receptor contains o-linked oligosaccharides" Journal of Biological Chemistry January 5 1990
  • "Characterization of the transferrin-binding protein in a human trophoblast." Placenta. Supplement  1981
  • "Cleavage of the transferrin receptor is influenced by the composition of the O-linked carbohydrate at position 104" Journal of Cellular Physiology August 1996
  • "Neogenin-mediated hemojuvelin shedding occurs after hemojuvelin traffics to the plasma membrane" Journal of Biological Chemistry June 20 2008
  • "Cutting edge" Journal of Immunology July 1 1999
  • "Iron homeostasis" Blood  2000
  • "Expression of the hereditary hemochromatosis protein HFE increases ferritin levels by inhibiting iron export in HT29 cells" Journal of Biological Chemistry June 11 2004
  • "Neogenin interacts with matriptase-2 to facilitate hemojuvelin cleavage" Journal of Biological Chemistry October 12 2012
  • "N-linked glycosylation is required for transferrin-induced stabilization of transferrin receptor 2, but not for transferrin binding or trafficking to the cell surface" Biochemistry May 14 2013
  • "Structure of human transferrin receptor oligosaccharides" Biochemistry April 29 1997
  • "Hereditary hemochromatosis and transferrin receptor 2" Biochimica et Biophysica Acta - General Subjects March 2012
  • "Iron in mammals" Topics in Current Genetics  2006
  • "Transferrin-directed internalization and cycling of transferrin receptor 2" Traffic October 2009
  • "Aspartate transcarbamoylase" Canadian Journal of Biochemistry June 1979
  • "HFE modulates transferrin receptor 2 levels in hepatoma cells via interactions that differ from transferrin receptor 1-HFE interactions" Journal of Biological Chemistry December 21 2007
  • "Transferrin receptor 2" Molecular Biology of the Cell March 2007
  • "Characterization of human foetal intestinal alkaline phosphatase. Comparison with the isoenzymes from the adult intestine and human tumour cell lines" Biochemical Journal  1983
  • "Mechanisms of HFE-induced regulation of iron homeostasis" Proceedings of the National Academy of Sciences of the United States of America August 5 2003
  • "A mutated transferrin receptor lacking asparagine-linked glycosylation sites shows reduced functionality and an association with binding immunoglobulin protein" Journal of Biological Chemistry September 15 1991
  • "Elimination of the O-linked glycosylation site at Thr 104 results in the generation of a soluble human-transferrin receptor" Blood January 15 1994

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