PKC-ζ controls cell polarity in a Ser1935 MHCII-B–dependent fashion. (A) Representative images display the localization of endogenous MHCII-A (top right) and MHCII-B (bottom right) and F-actin. Images are z projections of confocal stacks. (B) Effect of myristoylated (myr; constitutively active) PKC-ζ in cell polarity. Cells were transfected with FLAG-tagged wild type (top row) or myr–PKC-ζ (bottom row) and stained for endogenous MHCII-B (middle column) and F-actin (left column). FLAG staining (right column) denotes transfected cells. Representative cells are shown. (C) Reversion of myr–PKC-ζ induced depolarization by NMII-B mutants. Images depict representative cells cotransfected with FLAG-myr–PKC-ζ and the indicated GFP–MHCII-B construct. F-actin is shown in the left column, GFP-MHCII-B mutants are in the middle column, and FLAG is shown in the right column. (D) Quantification of the polarity index of cells as shown in C. Data are the means ± SD of >200 cells from four independent experiments, and p-value is the significance score in the Mann–Whitney test. Bars, 10 µm.