Cell Biology & Physiology Center, NHLBI, NIH, Bethesda, MD 20892, USA.
Department of Cellular & Molecular Medicine, University of Arizona, Tucson, AZ 85724, USA.
J Cell Sci. 2017 Jul 15;130(14):2405-2415. doi: 10.1242/jcs.200477. Epub 2017 Jun 5.
Endosomal trafficking can influence the composition of the plasma membrane and the ability of cells to polarize their membranes. Here, we examined whether trafficking through clathrin-independent endocytosis (CIE) affects the ability of T cells to form a cell-cell conjugate with antigen-presenting cells (APCs). We show that CIE occurs in both the Jurkat T cell line and primary human T cells. In Jurkat cells, the activities of two guanine nucleotide binding proteins, Arf6 and Rab22 (also known as Rab22a), influence CIE and conjugate formation. Expression of the constitutively active form of Arf6, Arf6Q67L, inhibits CIE and conjugate formation, and results in the accumulation of vacuoles containing lymphocyte function-associated antigen 1 (LFA-1) and CD4, molecules important for T cell interaction with the APC. Moreover, expression of the GTP-binding defective mutant of Rab22, Rab22S19N, inhibits CIE and conjugate formation, suggesting that Rab22 function is required for these activities. Furthermore, Jurkat cells expressing Rab22S19N were impaired in spreading onto coverslips coated with T cell receptor-activating antibodies. These observations support a role for CIE, Arf6 and Rab22 in conjugate formation between T cells and APCs.
内体运输可以影响质膜的组成以及细胞极化质膜的能力。在这里，我们研究了通过网格蛋白非依赖性内吞作用（CIE）是否会影响 T 细胞与抗原呈递细胞（APC）形成细胞-细胞连接的能力。我们表明，CIE 发生在 Jurkat T 细胞系和原代人 T 细胞中。在 Jurkat 细胞中，两种鸟嘌呤核苷酸结合蛋白（Arf6 和 Rab22（也称为 Rab22a））的活性影响 CIE 和连接体的形成。Arf6 的组成激活形式，Arf6Q67L 的表达抑制 CIE 和连接体的形成，并导致含有淋巴细胞功能相关抗原 1（LFA-1）和 CD4 的空泡积累，这些分子对于 T 细胞与 APC 的相互作用很重要。此外，Rab22 的 GTP 结合缺陷突变体 Rab22S19N 的表达抑制 CIE 和连接体的形成，表明 Rab22 的功能对于这些活性是必需的。此外，表达 Rab22S19N 的 Jurkat 细胞在覆盖有 T 细胞受体激活抗体的载玻片上扩散受到损害。这些观察结果支持 CIE、Arf6 和 Rab22 在 T 细胞与 APC 之间形成连接体中的作用。
