Transmembrane-4 superfamily proteins CD81 (TAPA-1), CD82, CD63, and CD53 specifically associated with integrin alpha 4 beta 1 (CD49d/CD29)
| Autor: | B A, Mannion, F, Berditchevski, S K, Kraeft, L B, Chen, M E, Hemler |
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| Rok vydání: | 1996 |
| Předmět: |
Antigens
Differentiation T-Lymphocyte Integrins Membrane Glycoproteins Tetraspanin 30 Receptors Lymphocyte Homing Antibodies Monoclonal Membrane Proteins Platelet Membrane Glycoproteins Tetraspanin 25 Integrin alpha4beta1 Kangai-1 Protein Cell Line Tetraspanin 28 Molecular Weight Antigens CD Proto-Oncogene Proteins Mutation Cell Adhesion Humans |
| Zdroj: | Journal of immunology (Baltimore, Md. : 1950). 157(5) |
| ISSN: | 0022-1767 |
| Popis: | Anti-alpha 4 integrin mAb coprecipitated CD81 (TAPA-1), a 25-kDa cell surface protein, from various alpha 4 beta1 -positive hemopoietic cell lines, including Molt4, Jurkat, Ramos, and alpha 4-transfected K562 (KX4C4) cells. In reciprocal experiments, the integrin alpha 4 beta 1 (VLA4, CD49d/CD29) could be reprecipitated from CD81 immunoprecipitates. Anti-alpha 4 integrin mAb also coprecipitated CD81 from the alpha 4 beta 7-positive B cell line RPMI 8866. In contrast, no CD81 was identified in alpha 2 beta 1, alpha 5 beta 1, or alpha L beta 2 immunoprecipitates. Abs to other members of the transmembrane-4 superfamily, including CD53, CD63, and CD82, also coprecipitated alpha 4 beta 1. As shown by confocal microscopy, CD81 and CD82 colocalized with alpha 4 beta 1 in cell surface clusters. The cytoplasmic domain of the alpha 4 integrin was not necessary for alpha 4 beta 1/CD81 association, nor was the association influenced by divalent cations, EDTA, integrin-activating mAb, or alpha 4 subunit cleavage. Notably, two independent alpha 4 adhesion-deficient mutants (D346E and D408E) were deficient in their ability to associate with CD81. Thus, CD81 and other transmembrane-4 superfamily members may participate in functionally relevant interactions with alpha 4 beta 1 and other integrins. |
| Databáze: | OpenAIRE |
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