The regulation of cell adhesion and motility is complex and requires the intracellular trafficking of integrins to and from sites of cell adhesion, especially in fast-moving cells such as leukocytes. The Rab family of guanosine triphosphatases (GTPases) is essential for vesicle transport, and vesicles mediate intracellular integrin trafficking. We showed that RhoB regulates the vesicular transport of the integrin LFA-1 along the microtubule network in migrating T lymphocytes. Impairment in RhoB function resulted in the accumulation of both LFA-1 and the recycling endosomal marker Rab11 at the rear of migrating T lymphocytes and decreased the association between these molecules. T lymphocytes lacking functional RhoB exhibited impaired recycling and subsequently decreased surface amounts of LFA-1, leading to reduced T cell adhesion and migration mediated by the cell adhesion molecule ICAM-1 (intercellular adhesion molecule–1). We propose that vesicle-associated RhoB is a regulator of the Rab11-mediated recycling of LFA-1 to the cell surface, an event that is necessary for T lymphocyte motility.

细胞粘附和运动的调节是复杂的，并且需要整联蛋白在细胞内向细胞粘附位点的往返运输，特别是在快速移动的细胞如白细胞中。鸟苷三磷酸酶（GTPases）的Rab家族对于囊泡运输至关重要，并且囊泡介导细胞内整联蛋白的运输。我们显示RhoB调节整合素LFA-1沿微管网络在迁移的T淋巴细胞中的囊泡运输。RhoB功能受损导致LFA-1和回收的内体标记Rab11都在迁移的T淋巴细胞的后部蓄积，并降低了这些分子之间的结合。缺乏功能性RhoB的T淋巴细胞显示出受损的循环能力，并随后降低了LFA-1的表面含量，导致细胞粘附分子ICAM-1（细胞间粘附分子-1）介导的T细胞粘附和迁移减少。我们建议囊泡相关的RhoB是Rab11介导的LFA-1到细胞表面的循环的调节器，这是T淋巴细胞运动所必需的。