Work

Joubert syndrome 26 protein enforces compartmentalized motility of a ciliary kinesin

Year: 2025

Type: article

Abstract: -cooperate to transport cargo along cilia, with kinesin-II operating in the middle segment and OSM-3 taking over distally. However, how kinesin-II is spatially confined to prevent its invasion into distal regions remains unclear. Here, we identify Joubert syndrome 26 protein (JBTS-26) as a critical regulator of this motor handover. JBTS-26 localizes to axonemal doublet microtubules in the ciliary middle segment, where it competes with kinesin-II for binding to the IFT-B subunit OSM-5/IFT88. This competition displaces kinesin-II from IFT particles, enabling OSM-3 to assume distal transport. Loss of JBTS-26 allows kinesin-II to invade the distal cilium and slows down IFT. Conversely, JBTS-26 overexpression accelerates IFT by prematurely releasing kinesin-II. Our findings reveal a mechanism for compartmentalized motor regulation and link defective motor handover to ciliopathy pathogenesis.

Source: Proceedings of the National Academy of Sciences

DOI: 10.1073/pnas.2504374122