Transmembrane-4 superfamily proteins CD81 (TAPA-1), CD82, CD63, and CD53 specifically associated with integrin alpha 4 beta 1 (CD49d/CD29).
Transmembrane-4 superfamily proteins CD81 (TAPA-1), CD82, CD63, and CD53 specifically associated with integrin alpha 4 beta 1 (CD49d/CD29).
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DOI：
10.4049/jimmunol.157.5.2039
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发表时间：
1996-09
影响因子：
4.4
通讯作者：
Brian A. Mannion;F. Berditchevski;S. Kraeft;Lan Bo Chen;M. Hemler
中科院分区：
文献类型：
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作者：
Brian A. Mannion;F. Berditchevski;S. Kraeft;Lan Bo Chen;M. Hemler
抗α 4整联蛋白mAb共沉淀来自各种α 4 β 1阳性造血细胞系（包括Molt 4、Jurkat、拉莫斯和α 4转染的K562（KX 4C 4）细胞）的25 kDa细胞表面蛋白CD 81（TAPA-1）。在交互实验中，整合素α 4 β 1（VLA 4，CD 49 d/CD 29）可从CD 81免疫沉淀物中再沉淀。抗α 4整联蛋白mAb还从α 4 β 7阳性B细胞系RPMI 8866共沉淀CD 81。相比之下，在α 2 β 1、α 5 β 1或α L β 2免疫沉淀物中未鉴定出CD 81。针对跨膜-4超家族其他成员的抗体，包括CD 53、CD 63和CD 82，也共沉淀α 4 β 1。如共聚焦显微镜所示，CD 81和CD 82与α 4 β 1共定位在细胞表面簇中。α 4整联蛋白的胞质结构域对于α 4 β 1/CD 81缔合不是必需的，缔合也不受二价阳离子、EDTA、整联蛋白活化mAb或α 4亚基裂解的影响。值得注意的是，两个独立的α 4粘附缺陷型突变体（D346 E和D408 E）在其与CD 81缔合的能力方面是缺陷的。因此，CD 81和其他跨膜-4超家族成员可能参与与α 4 β 1和其他整合素的功能相关相互作用。
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.