Gateway to the cilium - The Scientist - Magazine of the Life Sciences
Abstract
Courtesy of John Dishinger The paper J.F. Dishinger et al., “Ciliary entry of the kinesin-2 motor KIF17 is regulated by importin-b2 and RanGTP," Nat Cell Biol, 12:703-10, 2010. Free F1000 Evaluation The finding Primary cilia are tiny, hair-like organelles on the surface of cells, and are important in functions such as vision and smell. The composition of cilia membranes is different from the rest of the cell membrane due to a ring of proteins (septins) that act as a roadblock to diffusion. But how ciliary cytoplasmic proteins arrive at their specific destination was unknown. Kristen Verhey’s group at the University of Michigan Medical School identified a traffic-signaling sequence that cells append to proteins destined for the cilia. The surprise Verhey’s group was studying a kinesin motor protein called KIF17 when they noticed that some mutants did not enter the cilium. The mutant sequences had signaling motifs on their tail ends that looked exactly like those known to direct proteins to the nuclear pore. “We thought, ‘that’s really weird,’” says Verhey. “Why would mutating something that looks like a nuclear localization signal prevent ciliary localization?” The known Verhey’s group showed that trafficking cytoplasmic proteins to the cilium involves the