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This Article Full Text Full Text (PDF) 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 Anzai, N. Articles by Broxmeyer, H. E. Search for Related Content PubMed PubMed Citation Articles by Anzai, N. Articles by Broxmeyer, H. E. Related Collections Hematopoiesis and Stem Cells Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  Blood, 15 June 2002, Vol. 99, No. 12, pp. 4413-4421 HEMATOPOIESIS c-kit associated with the transmembrane 4 superfamily proteins constitutes a functionally distinct subunit in human hematopoietic progenitors Naoyuki Anzai, Younghee Lee, Byung-S. Youn, Seiji Fukuda, Young-June Kim, Charlie Mantel, Makoto Akashi, and Hal E. Broxmeyer From the Departments of Microbiology/Immunology, Medicine, and the Walther Oncology Center, Indiana University School of Medicine, Indianapolis; the Walther Cancer Institute, Indianapolis, Indiana; and the Research Center for Radiation Emergency Medicine, National Institute of Radiological Sciences, Chiba, Japan. The transmembrane 4 superfamily (TM4SF) has come into prominence for its association with a wide range of cell surface molecules, especially integrins. We report that TM4SF molecules CD9, CD63, and CD81 are physically associated with c-kit receptor tyrosine kinase in the human factor-dependent myeloid cell line, MO7e. We characterized this complex using coimmunoprecipitation and colocalization methods. The c-kit coimmunoprecipitated with anti-TM4SF antibodies showed several distinct phenotypes compared to the total c-kit immunoprecipitated with anti-c-kit antibody. These included: (1) higher basal level of tyrosine phosphorylation without elevated kinase activity in the absence of Steel factor (SLF), (2) deficient enhancement of tyrosine phosphorylation and kinase activity in response to SLF, (3) elevated binding rate of SLF shown in chemical cross-linking studies, and (4) little internalization and degradation after SLF treatment. Cocapping studies in living cells showed that c-kit colocalized with TM4SF molecules after SLF stimulation, suggesting confirmation of the biochemical data obtained by the coimmunoprecipitation studies. Colocalization of c-kit with CD81 by SLF was also observed in cord blood CD34+ cells, suggesting the existence of functional units of c-kit in TM4SF complexes in primary hematopoietic cells. This suggests that some TM4SF members may negatively modulate function of c-kit receptor tyrosine kinase and thus regulate receptor sensitivity to SLF in hematopoietic progenitors. © 2002 by The American Society of Hematology.   CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? This article has been cited by other articles: X. Yang, O. V. Kovalenko, W. Tang, C. Claas, C. S. Stipp, and M. E. Hemler Palmitoylation supports assembly and function of integrin-tetraspanin complexes J. Cell Biol., December 20, 2004; 167(6): 1231 - 1240. [Abstract] [Full Text] [PDF] J. Lennartsson, R. Shivakrupa, and D. Linnekin Synergistic Growth of Stem Cell Factor and Granulocyte Macrophage Colony-stimulating Factor Involves Kinase-dependent and -independent Contributions from c-Kit J. Biol. Chem., October 22, 2004; 279(43): 44544 - 44553. [Abstract] [Full Text] [PDF]

	Copyright © 2002 by American Society of Hematology         Online ISSN: 1528-0020