(A) Highly simplified schematic of the intraflagellar transport cycle in a cilium. The closed BBSome complex (green) binds the intraflagellar transport machinery (IFT, blue) at the base of the cilium and starts travelling towards the tip of the cilium along a structure called the axoneme (grey), which is formed by microtubules. Once near the tip, the complex binds ARL6, becoming activated, and it can take ciliary membrane proteins (red) as cargo and transport them to the base of the cilium. At this point, the BBSome releases its cargo (which remains embedded in the membrane) and dissociates from the IFT machinery. (B) Cartoon representation of closed and open conformations of bovine and human BBSome complexes with each subunit represented in a different color.