The small GTPases ARL-13 and ARL-3 coordinate intraflagellar transport and ciliogenesis.
Intraflagellar transport (IFT) machinery mediates the bidirectional movement of cargos that are required for the assembly and maintenance of cilia. However, little is known about how IFT is regulated in vivo. In this study, we show that the small guanosine triphosphatase (GTPase) adenosine diphosphate ribosylation factor-like protein 13 (ARL-13) encoded by the Caenorhabditis elegans homologue of the human Joubert syndrome causal gene ARL13B, localizes exclusively to the doublet segment of the cilium. arl-13 mutants have shortened cilia with various ultrastructural deformities and a disrupted association between IFT subcomplexes A and B. Intriguingly, depletion of ARL-3, another ciliary small GTPase, partially suppresses ciliogenesis defects in arl-13 mutants by indirectly restoring binding between IFT subcomplexes A and B. Rescue of arl-13 mutants by ARL-3 depletion is mediated by an HDAC6 deacetylase-dependent pathway. Thus, we propose that two conserved small GTPases, ARL-13 and ARL-3, coordinate to regulate IFT and that perturbing this balance results in cilia deformation.
Division of Nephrology and Hypertension, Department of Internal Medicine, and 2 Department of Biochemistry and Molecular Biology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
Yujie
Y
Li
Qing
Q
Wei
Yuxia
Y
Zhang
Kun
K
Ling
Jinghua
J
Hu
D000818:Animals; D030801:Animals, Genetically Modified; D001692:Biological Transport / Q000502:physiology; D017173:Caenorhabditis elegans / Q000166:cytology / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D002923:Cilia / Q000502:physiology* / Q000648:ultrastructure; D005407:Flagella / Q000378:metabolism* / Q000648:ultrastructure; D006655:Histone Deacetylases / Q000235:genetics / Q000378:metabolism; D006801:Humans; D016547:Kinesins / Q000378:metabolism; D020559:Monomeric GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
D029742:Caenorhabditis elegans Proteins; D011993:Recombinant Fusion Proteins; D006655:Histone Deacetylases; D016547:Kinesins; C550601:ARL-13 protein, C elegans; C550602:ARL-3 protein, C elegans; D020559:Monomeric GTP-Binding Proteins