WDR62 is required for katanin localization at spindle poles. (A–D) Immunofluorescence images of metaphase RPE1 cells treated with siCTRL or siWDR62, stained with DAPI, antibodies against γ-tubulin, and KATNB1 (A), ASPM (B), KIF2A (C), or MCAK (D). (E) Quantification of protein levels at spindle poles in siWDR62 relative to siCTRL: N = 5; n = 286–328 cells; dot plot represents median per experiment; bars represent mean ± SEM; ***, P < 0.001, two-tailed paired t test. (F) Immunofluorescence images of RPE1 eGFP or WDR62-eGFP metaphase cells transfected with indicated siRNA, stained with KATNB1 and pericentrin antibodies, and DAPI. (G) Quantification of KATNB1 levels at spindle poles as shown in F: N = 5, n = 263–279 cells; dot plot represents median per experiment; bars represent mean ± SEM; ****, P < 0.0001, one-way ANOVA. (H) Western blot of asynchronous RPE1 cell lysates treated with siCTRL or siWDR62 and probed against WDR62, KATNB1, and β-actin (loading control). (I) Quantification of immunoblot shown in H of KATNB1/β-actin and WDR62/β-actin ratio signal in siWDR62 relative to siCTRL. N = 1. (J and K) Immunofluorescence images of metaphase RPE1 cells treated with indicated siRNA, stained with WDR62, pericentrin antibodies, and DAPI. (L) Quantifications of WDR62 levels at spindle poles in siASPM and siKATNB1 relative to siCTRL: N = 5; n = 320–339 cells; dot plot represents median per experiment; bars represent mean ± SEM; *, P < 0.05; ***, P < 0.001, two-tailed paired t test. All scale bars = 5 µm.