The growing ends of microtubules point toward the actin/myosin ring during extrusion. (a and b) EB1 (green), a plus-end microtubule-binding protein, colocalizes with the myosin II (red) ring during apical (a) and basal (b) extrusion. Arrows point to sites where EB1 abuts the myosin II ring. Note that most EB1 is from 0–4 µm from the base during apical extrusion, whereas during basal extrusion, only limited amounts of EB1 are seen at the apex (6 µm from the base). Bars, 10 µm. (c) Quantification of EB1 localization (>170 spots for each) from 12 extrusions each of apically extruding cells, basally extruding cells, and live junctions. Error bars indicate SEM and P < 0.0001, comparing spots from apical extrusion to basal extrusion.