The microtubule motor dynein-2 is responsible for retrograde intraflagellar transport (IFT), a process critical for cilia assembly and cilium-dependent signaling. Mutations in genes encoding dynein-2 subunits interfere with ciliogenesis and are among the most frequent causes of skeletal ciliopathies. Despite its importance, little is known regarding dynein-2 assembly and regulation. Here, we identify the molecular HSP90 chaperone as a critical regulator of dynein-2 complex stability and function. Pharmacological inhibition of HSP90 causes a severe decrease in the levels of dynein-2 subunits, without detectable alterations in cytoplasmic dynein-1 and the anterograde IFT kinesin-2 motor KIF3A. Consistent with disrupted dynein-2 function, HSP90 inhibition progressively disrupts retrograde IFT and severely impairs ciliogenesis. We demonstrate that HSP90 associates with the dynein-2 complex, promoting its assembly and stabilization. These results establish dynein-2 as a novel HSP90 client and provide important mechanistic insights into the regulation of dynein-2 assembly.
Dantas et al. (Thu,) studied this question.