Zhang, An-Sheng and West, Anthony P. , Jr. and Wyman, Anne E. and Bjorkman, Pamela J. and Enns, Caroline A. (2005) Interaction of hemojuvelin with neogenin results in iron accumulation in human embryonic kidney 293 cells. Journal of Biological Chemistry, 280 (40). pp. 33885-33894. ISSN 0021-9258 http://resolver.caltech.edu/CaltechAUTHORS:ZHAjbc05
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Type 2 hereditary hemochromatosis (HH) or juvenile hemochromatosis is an early onset, genetically heterogeneous, autosomal recessive disorder of iron overload. Type 2A HH is caused by mutations in the recently cloned hemojuvelin gene (HJV; also called HFE2) (Papanikolaou, G., Samuels, M. E., Ludwig, E. H., MacDonald, M. L., Franchini, P. L., Dube, M. P., Andres, L., MacFarlane, J., Sakellaropoulos, N., Politou, M., Nemeth, E., Thompson, J., Risler, J. K., Zaborowska, C., Babakaiff, R., Radomski, C. C., Pape, T. D., Davidas, O., Christakis, J., Brissot, P., Lockitch, G., Ganz, T., Hayden, M. R., and Goldberg, Y. P. (2004) Nat. Genet. 36, 77–82), whereas Type 2B HH is caused by mutations in hepcidin. HJV is highly expressed in both skeletal muscle and liver. Mutations in HJV are implicated in the majority of diagnosed juvenile hemochromatosis patients. In this study, we stably transfected HJV cDNA into human embryonic kidney 293 cells and characterized the processing of HJV and its effect on iron homeostasis. Our results indicate that HJV is a glycosylphosphatidylinositol-linked protein and undergoes a partial autocatalytic cleavage during its intracellular processing. HJV co-immunoprecipitated with neogenin, a receptor involved in a variety of cellular signaling processes. It did not interact with the closely related receptor DCC (deleted in Colon Cancer). In addition, the HJV G320V mutant implicated in Type 2A HH did not co-immunoprecipitate with neogenin. Immunoblot analysis of ferritin levels and transferrin-55Fe accumulation studies indicated that the HJV-induced increase in intracellular iron levels in human embryonic kidney 293 cells is dependent on the presence of neogenin in the cells, thus linking these two proteins to intracellular iron homeostasis.
|Additional Information:||© 2005 by The American Society for Biochemistry and Molecular Biology, Inc. Received for publication, June 7, 2005, and in revised form, July 28, 2005. We thank Dr. Silvia Arber for rabbit anti-HJV peptide antibody, Dr. Jan Christian for mouse anti-Myc monoclonal antibody, Dr. Eric R. Fearon for human neogenin cDNA, Dr. Anna Velcich for HT29-DCC11 and HT29-neo cells, and members of the Enns laboratory for critical reading of the manuscript. This work was supported by National Institutes of Health Grants DK54488 (to C.A. E.) and R01 DK60770 (to P.J.B.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.|
|Subject Keywords:||REPULSIVE GUIDANCE MOLECULE; HEREDITARY HEMOCHROMATOSIS PROTEIN; 1Q-LINKED JUVENILE HEMOCHROMATOSIS; CHROMOSOME 1Q; TRANSFERRIN RECEPTOR; EXPRESSION PATTERN; GENE-MUTATIONS; LOCUS MAPS; HFE; RGM|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Lindsay Cleary|
|Deposited On:||27 Oct 2006|
|Last Modified:||26 Dec 2012 09:14|
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