K14 and K15 display distinct staining patterns in vivo and ex vivo. (A) Diagram of K14 and K15 primary structures. Boxes represent coiled-coil regions. Schematic comparing the orthologous residues between K14 and K15 in the putative regulatory regions in the head and 2B rod domains. Mouse K14 contains four cysteines in the head domain and two in the 2B rod domain. Mouse K15 contains one cysteine residue in the head domain and two in the 2B rod domain. * K15 does not have a cysteine orthologous to mK14 C373 (mK15 C373 is downstream of the mK15 stutter region). (B) Individual immunostaining with magnified inset for K14 in formalin-fixed, paraffin-embedded human buttock skin. K14 individual immunostaining extends into the suprabasal compartment. A dashed line specifies the basal lamina; epi, epidermis; derm, dermis. Scale bar, 50 µm. (B′) Individual immunostaining with magnified inset for K15 in formalin-fixed, paraffin-embedded human buttock skin. K15 individual immunostaining is restricted to the basal layer. A dashed line specifies the basal lamina; epi, epidermis; derm, dermis. Scale bar, 50 µm. (C) Individual immunostaining for K14 and K15 in skin keratinocytes harvested from neonatal Krt14C373A/WT pups and seeded in primary culture. Scale bar, 50 µm. (C′) Scatter plots representing the K14 and K15 MIVs of individually traced cells in Fig. 1 C (arbitrary units, mean ± SD). (D) Multiplexed immunostaining for K15 (red), K14 (green), and K10 (magenta). Nuclei are counterstained with DAPI (blue). A dashed line specifies the basal lamina. epi, epidermis; derm, dermis. Scale bar, 50 µm.