Rab35 controls cilium length, function and membrane composition

Stefanie Kuhns (1, 2) , Cecília Seixas (3) , Sara Pestana (3) , Bárbara Tavares (3) , Renata Nogueira (3) , Raquel Jacinto (3) , José Ramalho (3) , Jeremy Simpson (1) , Jens Andersen (2) , Arnaud Echard (4) , Susana Lopes (3) , Duarte Barral (3) , Oliver Blacque (1)

1 UCD - University College Dublin [Dublin]
2 SDU - University of Southern Denmark
3 NOVA - Universidade Nova de Lisboa = NOVA University Lisbon
4 Trafic membranaire et Division cellulaire - Membrane Traffic and Cell Division

Rab and Arl guanine nucleotide-binding (G) proteins regulate trafficking pathways essential for the formation, function and composition of primary cilia, which are sensory devices associated with Sonic hedgehog (Shh) signalling and ciliopathies. Here, using mammalian cells and zebrafish, we uncover ciliary functions for Rab35, a multitasking G protein with endocytic recycling, actin remodelling and cytokinesis roles. Rab35 loss via siRNAs, morpholinos or knockout reduces cilium length in mammalian cells and the zebrafish left-right organiser (Kupffer's vesicle) and causes motile cilia-associated left-right asymmetry defects. Consistent with these observations, GFP-Rab35 localises to cilia, as do GEF (DENND1B) and GAP (TBC1D10A) Rab35 regulators, which also regulate ciliary length and Rab35 ciliary localisation. Mammalian Rab35 also controls the ciliary membrane levels of Shh signalling regulators, promoting ciliary targeting of Smoothened, limiting ciliary accumulation of Arl13b and the inositol polyphosphate 5-phosphatase (INPP5E). Rab35 additionally regulates ciliary PI(4,5)P2 levels and interacts with Arl13b. Together, our findings demonstrate roles for Rab35 in regulating cilium length, function and membrane composition and implicate Rab35 in pathways controlling the ciliary levels of Shh signal regulators.

Mots clés: Rab35; cilia; left-right asymmetry; Arl13b; Smoothened

Domaines: Biologie cellulaire

Stefanie Kuhns, Cecília Seixas, Sara Pestana, Bárbara Tavares, Renata Nogueira, et al.. Rab35 controls cilium length, function and membrane composition. EMBO Reports, 2019, 20 (10), ⟨10.15252/embr.201847625⟩. ⟨hal-03084693⟩