Membrane blebbing‐dependent (blebby) amoeboid migration can be employed by lymphoid and cancer cells to invade 3D‐environments. Here, we reveal a mechanism by which the small GTPase RhoB controls membrane blebbing and blebby amoeboid migration. Interestingly, while all three Rho isoforms (RhoA, RhoB and RhoC) regulated amoeboid migration, each controlled motility in a distinct manner. In particular, RhoB depletion blocked membrane blebbing in ALL (acute lymphoblastic leukaemia), melanoma and lung cancer cells as well as ALL cell amoeboid migration in 3D‐collagen, while RhoB overexpression enhanced blebbing and 3D‐collagen migration in a manner dependent on its plasma membrane localization and down‐stream effectors ROCK and Myosin II. RhoB localization was controlled by endosomal trafficking, being internalized via Rab5 vesicles and then trafficked either to late endosomes/lysosomes or to Rab11‐positive recycling endosomes, as regulated by KIF13A. Importantly, KIF13A depletion not only inhibited RhoB plasma membrane localization, but also cell membrane blebbing and 3D‐migration of ALL cells. In conclusion, KIF13A‐mediated endosomal trafficking modulates RhoB plasma membrane localization to control membrane blebbing and blebby amoeboid migration.

淋巴样和癌细胞可以利用膜起泡依赖性（脆弱的）变形虫迁移来入侵3D环境。在这里，我们揭示了一种机制，小GTP酶RhoB通过该机制控制膜起泡和肮脏的变形虫迁移。有趣的是，尽管所有三种Rho亚型（RhoA，RhoB和RhoC）均能调节类阿米巴的迁移，但每种都以不同的方式控制运动。特别是RhoB耗竭阻止了ALL（急性淋巴细胞白血病），黑色素瘤和肺癌细胞的膜起泡以及3D胶原蛋白中ALL细胞的类弹体迁移，而RhoB的过表达以取决于血浆的方式增强了起泡和3D胶原蛋白的迁移。膜定位和下游效应器ROCK和Myosin二。RhoB的定位受内体运输的控制，通过Rab5囊泡被内在化，然后按照KIF 13A的规定运输到晚期内体/溶酶体或Rab11阳性回收内体。重要的是，KIF 13A消耗不仅抑制RhoB质膜定位，而且还抑制细胞膜起泡和ALL细胞的3D迁移。总之，KIF 13A介导的内体运输调节RhoB质膜定位，以控制膜起泡和不良的变形虫迁移。