Check out our new preprint on the role of Rab34 GTPase in primary cilium assembly! We find that Rab34 mediates ciliary membrane formation selectively in the intracellular pathway of ciliogenesis (used in fibroblasts) but not the extracellular pathway (used by polarized epithelial cells). Likewise, Rab34 marks assembly intermediates and ciliary substructures unique to the intracellular ciliogenesis pathway. This gives new molecular insight into how different cells use different pathways to make cilia. Plus there is GTPase biochemistry, FIB-SEM of nascent cilia, expansion microscopy, SIM imaging and more.