Fig. 9. Microtubule and CAP350 deployment in cochlear supporting cells. (A) Schematic diagram of the microtubule organisation (red lines) in a typical inner pillar cell at P5 (5 days postnatal) showing the apical centrosome (green with centrioles/primary cilium in red) and the microtubule minus-ends (arrowhead) anchored at apical sites (blue peripheral ring; arrow). (B) Apical view of a 3D reconstruction (based on confocal optical sections) of the apex of two inner pillar cells (P5) showing microtubules (red) organised in a tube and their minus ends forming an apical peripheral ring. CAP350 (green) is concentrated at the centrioles, which are located above the middle of the tube of microtubules (see A). Note there is no accumulation of CAP350 at the peripheral ring where some 3000 microtubule minus ends are located (arrow). (C) Lateral view of a 3D of the apical region of three inner pillar cells (P5) showing the apico-basally aligned microtubules with their minus-ends at the apex. CAP350 is concentrated at the centrosome (located above the microtubule array) and diffuse in the cytoplasm surrounding the microtubules. Note the cytoplasmic diffuse CAP350 is not evident at the minus ends of the microtubules and shows no apparent association with the microtubule array. (D) Apical view of a 3D reconstruction (based on confocal optical sections) of the apex of an inner pillar cell (P5) showing ninein at the centrosome and concentrated in a peripheral ring. (E) Lateral-to-oblique view of a 3D image of the apical region of an inner pillar cell (P5) with ninein accumulated at the minus ends of the apico-basal microtubules (red) (arrowhead). Part of the apex is also apparent, revealing part of the peripheral ninein ring (arrow) and ninein concentrated at the two centrioles. Bars, 5 µm.