Specific role of centrosomal subdistal appendages (SAs) in stabilizing centriole microtubules (MTs). (A) Immunofluorescence images of MTs in DA+SA+, DA+SA−, and DA−SA− centrioles under nocodazole treatment, an MT-destabilizing condition. WT, (DA+SA+) centriole in WT F9 cells; Δ4/5, (DA+SA−) centriole in Δ4/5 construct–expressing Odf2-KO F9 cells; Δ6/7, (DA+SA+) centriole in Δ6/7 construct–expressing Odf2-KO F9 cells. (B) Quantification of MT stability. The relative MT stability is shown for the indicated Odf2 construct (*, P = 0.01; **, P = 0.005; n > 200 in more than three independent experiments). (C) Schematic drawing of the specific roles of the appendages of ciliary basal bodies/centrioles. In the proposed model, separate domains in Odf2 serve as the molecular platform on which the appendages are constructed. Note that centriolin associates with ODF2/cenexin at the base of the SA (or where the base would be in the absence of SAs), and recruits vesicles whose cargoes support ciliogenesis. The BF/SAs (red) stabilize MTs, whereas the TFs/DAs (blue) are essential for ciliogenesis. MC, mother centriole; DC, daughter centriole.