HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 282, Issue 18, 13884-13894, May 4, 2007

This Article Full Text Full Text (PDF) All Versions of this Article: 282/18/13884    most recent M701027200v1 Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted 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 Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Pang, D. J. Articles by Bijlmakers, M.-J. Search for Related Content PubMed PubMed Citation Articles by Pang, D. J. Articles by Bijlmakers, M.-J. Social Bookmarking                      What's this?

CD8 Raft Localization Is Induced by Its Assembly into CD8 Heterodimers, Not CD8 Homodimers^*

From the Peter Gorer Department of Immunobiology, King's College London, School of Medicine at Guy's Hospital, London SE1 9RT, United Kingdom

The coreceptor CD8 is expressed as a CD8 heterodimer on major histocompatibility complex class I-restricted TCR T cells, and as a CD8 homodimer on subsets of memory T cells, intraepithelial lymphocytes, natural killer cells, and dendritic cells. Although the role of CD8 is not well understood, it is increasingly clear that this protein is not a functional homologue of CD8. On major histocompatibility complex class I-restricted T cells, CD8 is a more efficient TCR coreceptor than CD8. This property has for the mouse protein been attributed to the recruitment of CD8 into lipid rafts, which is dependent on CD8 palmitoylation. Here, these divergent distributions of CD8 and CD8 are demonstrated for the human CD8 proteins as well. However, although palmitoylation of both CD8 and CD8 chains was detected, this modification did not contribute to raft localization. In contrast, arginines in the cytoplasmic domain are crucial for raft localization of CD8. Most strikingly, the assembly of a non-raft localized CD8 chain with a non-raft localized CD8 chain resulted in raft-localized CD8 heterodimers. Using chimeric CD8 proteins, this property of the heterodimer was found to be determined by the assembly of CD8 and CD8 extracellular regions. The presence of two CD8 extracellular regions, on the other hand, appears to preclude raft localization. Thus, heterodimer formation and raft association are intimately linked for CD8. These results emphasize that lipid raft localization is a key feature of human CD8 that clearly distinguishes it from CD8.

Received for publication, February 2, 2007

^* This work was supported by grants from the Medical Research Council (to M.-J. B.) and The Wellcome Trust (to A. C. H.). 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.

¹ Supported by a King's College London Alumni (KCLA) Research Studentship.

² To whom correspondence should be addressed: Dept. of Immunobiology, King's College London, School of Medicine at Guy's Hospital, 2nd Floor New Guy's House, London SE1 9RT, United Kingdom. Tel.: 44-20-718-83060; Fax: 44-20-718-83385; E-mail: marie.bijlmakers{at}kcl.ac.uk.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				J. C. Varghese and K. P. Kane TCR Complex-Activated CD8 Adhesion Function by Human T Cells J. Immunol., November 1, 2008; 181(9): 6002 - 6009. [Abstract] [Full Text] [PDF]

				D. Thakral, J. Dobbins, L. Devine, and P. B. Kavathas Differential Expression of the Human CD8{beta} Splice Variants and Regulation of the M-2 Isoform by Ubiquitination J. Immunol., June 1, 2008; 180(11): 7431 - 7442. [Abstract] [Full Text] [PDF]