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Blood, 1 February 2007, Vol. 109, No. 3, pp. 1284-1288. Prepublished online as a Blood First Edition Paper on September 28, 2006; DOI 10.1182/blood-2006-07-036954. This Article Full Text Full Text (PDF) All Versions of this Article: blood-2006-07-036954v1 109/3/1284    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by An, X. Articles by Mohandas, N. Search for Related Content PubMed PubMed Citation Articles by An, X. Articles by Mohandas, N. Related Collections Red Cells Cytoskeleton Related Article in Blood Online Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  RED CELLS Tropomyosin modulates erythrocyte membrane stability Xiuli An1, Marcela Salomao1, Xinhua Guo1, Walter Gratzer2, and Narla Mohandas1 1 Red Cell Physiology Laboratory, New York Blood Center, New York, NY; 2 Kings College London, Randall Center for Molecular Mechanisms of Cell Function, Guy's Campus, London, United Kingdom The ternary complex of spectrin, actin, and 4.1R (human erythrocyte protein 4.1) defines the nodes of the erythrocyte membrane skeletal network and is inseparable from membrane stability under mechanical stress. These junctions also contain tropomyosin (TM) and the other actin-binding proteins, adducin, protein 4.9, tropomodulin, and a small proportion of capZ, the functions of which are poorly defined. Here, we have examined the consequences of selective elimination of TM from the membrane. We have shown that the mechanical stability of the membranes of resealed ghosts devoid of TM is grossly, but reversibly, impaired. That the decreased membrane stability of TM-depleted membranes is the result of destabilization of the ternary complex of the network junctions is demonstrated by the strongly facilitated entry into the junctions in situ of a ß-spectrin peptide, containing the actin- and 4.1R-binding sites, after extraction of the TM. The stabilizing effect of TM is highly specific, in that it is only the endogenous isotype, and not the slightly longer muscle TM that can bind to the depleted membranes and restore their mechanical stability. These findings have enabled us identify a function for TM in elevating the mechanical stability of erythrocyte membranes by stabilizing the spectrin-actin-4.1R junctional complex. CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? Related Article in Blood Online: Complexity at the junction Patrick G. Gallagher Blood 2007 109: 854-855. [Full Text] [PDF] This article has been cited by other articles: N. Vlahovich, A. J. Kee, C. Van der Poel, E. Kettle, D. Hernandez-Deviez, C. Lucas, G. S. Lynch, R. G. Parton, P. W. Gunning, and E. C. Hardeman Cytoskeletal Tropomyosin Tm5NM1 Is Required for Normal Excitation-Contraction Coupling in Skeletal Muscle Mol. Biol. Cell, January 1, 2009; 20(1): 400 - 409. [Abstract] [Full Text] [PDF] M. Salomao, X. Zhang, Y. Yang, S. Lee, J. H. Hartwig, J. A. Chasis, N. Mohandas, and X. An Protein 4.1R-dependent multiprotein complex: New insights into the structural organization of the red blood cell membrane PNAS, June 10, 2008; 105(23): 8026 - 8031. [Abstract] [Full Text] [PDF]

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