Microtubule-anchoring activity of LL5s. (A and B) Effects of LL5 depletion on the distributions of CLASP1 and microtubules at the basal cortex. Parental MCF-10Aeco cells or cells expressing myc3-LL5α(res) or myc3-LL5β(res) were transfected with the indicated siRNAs, seeded on coverslips, fixed, and stained for LL5s (LL5α alone, LL5β alone, or LL5α+β), CLASP1, and microtubules. (A) Images of the basal cortex were collected using a confocal microscope. (B) The fluorescence intensities of LL5s, CLASP1, and microtubules at the lamellipodia were analyzed and plotted. The data were transformed into a relative fluorescence index. The fluorescence intensities of the mock control were set as 1. The results are presented as means ± SEM (*, P < 0.01 vs. the mock control). (C and D) LL5β recruits microtubules to the basal cortex through its middle region. (C) Under LL5-depleted conditions, parental MCF-10Aeco cells or cells expressing myc3-LL5β(res) or myc3-LL5β(ΔM) were fixed and stained for myc tag, CLASP1, and microtubules. (D) The fluorescence intensities of myc tag, CLASP1, and microtubules at the lamellipodia were analyzed and plotted. The data were transformed into a relative fluorescence index. The fluorescence intensities of the myc3-LL5β–expressing cells were set as 1. Myc3-LL5β(ΔM) is unable to recruit CLASP1/microtubules. The results are presented as means ± SEM (*, P < 0.01 vs. the LL5α+β siRNA + myc3-LL5β(res) sample). Bars, 10 µm.