Formation and/or maintenance of perinuclear keratin networks are compromised by loss of K14-bound cysteines and/or disulfide bonding. (A) Immunofluorescence imaging reveals three distinct modes of organization for K14-containing filament networks in primary culture of Krt14^−/− mouse keratinocytes transfected with either GFP-K14WT or GFP-K14CF: “pan-cytoplasmic,” “perinuclear-concentrated,” and “peripheral” IF networks. Bar, 10 µm. (B) Frequency of each type of IF network as illustrated in A. Data are presented as mean ± SD from three independent experiments. (C) Still images from live movie recordings comparing keratinocytes expressing GFP-K14WT and GFP-K14CF (green channel). H2B-mCherry (red channel) was cotransfected to visualize nuclei. The images shown correspond to seven time points, from 0 to 6 h, in movies recorded using laser scanning confocal microscopy (see Videos 1 and 2). N, nucleus. Bar, 10 µm. (D) 2.5-dimensional views of z-stacked images at time 0, 3, and 6 h show GFP-K14WT– or GFP-K14CF-containing networks in the cytoplasm (green channel) and H2B-mCherry–labeled nucleus (red channel) in transfected keratinocytes.