Ciliogenesis is a coordinated process initiated by the recruitment and fusion of pre-ciliary vesicles at the distal appendages of the mother centriole through mechanisms that remain unclear. Here, we report that EFA6A (also known as PSD), an exchange factor for the small G protein Arf6, is involved in early stage of ciliogenesis by promoting the fusion of distal appendage vesicles forming the ciliary vesicle. EFA6A is present in the vicinity of the mother centriole before primary cilium assembly and prior to the arrival of Arl13B-containing vesicles. During ciliogenesis, EFA6A initially accumulates at the mother centriole and later colocalizes with Arl13B along the ciliary membrane. EFA6A depletion leads to the inhibition of ciliogenesis, the absence of centrosomal Rab8-positive structures and the accumulation of Arl13B-positive vesicles around the distal appendages. Our results uncover a novel fusion machinery, comprising EFA6A, Arf6 and Arl13B, that controls the coordinated fusion of ciliary vesicles docked at the distal appendages of the mother centriole.

纤毛发生是一个协调过程，通过尚不清楚的机制在母体中心粒的远端附肢处招募和融合前睫状体囊泡。在这里，我们报告 EFA6A（也称为 PSD），一种小 G 蛋白 Arf6 的交换因子，通过促进形成睫状囊泡的远端附属囊泡融合而参与纤毛发生的早期阶段。在初级纤毛组装之前和含有 Arl13B 的囊泡到达之前，EFA6A 存在于母中心粒附近。在纤毛发生过程中，EFA6A 最初聚集在母体中心粒，然后与 Arl13B 沿睫状膜共定位。EFA6A 耗竭导致纤毛发生抑制，中心体 Rab8 阳性结构的缺失和远端附肢周围 Arl13B 阳性囊泡的积累。我们的研究结果揭示了一种新的融合机制，包括 EFA6A、Arf6 和 Arl13B，它控制停靠在母体中心粒远端附件的睫状囊泡的协调融合。