1. Growth Retardation, Loss of Desmosomal Adhesion, and Impaired Tight Junction Function Identify a Unique Role of Plakophilin 1 In Vivo 
Katrin Rietscher, Annika Wolf, Gerd Hause, Annekatrin Rother, René Keil, Thomas M. Magin, Markus Glass, Carien M. Niessen, Mechthild Hatzfeld 
Journal of Investigative Dermatology 
Volume 136, Issue 7, Pages (July 2016)
DOI: /j.jid
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2. Figure 1
PKP1–/– mice suffer from skin fragility and reduced birth weight. (a) Representative PKP1+/+ and PKP1–/– newborn pups. Note that the PKP1-KO mouse shows wounds and fragile skin. Scale bar = 1 cm. (b) Measurement of birth weight of PKP1-KO mice (n = 23) compared with wild-type littermates (n = 18). ***P < (c) Western blot analysis of total protein from newborn PKP1+/+, +/–, and –/– dorsal skin. PKP1 was probed with antibodies against N- and C-terminal domains. Vinculin and α-tubulin were used as loading controls. PKP, plakophilin; term., terminal; WT, wild-type.
Journal of Investigative Dermatology  , DOI: ( /j.jid )
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3. Figure 2
PKP1–/– skin shows cell separation, reduced desmosomes, and a reduced adipocyte layer. (a) Dorsal and (b) paw skin of PKP1+/+ and PKP1–/– pups was stained with hematoxylin and eosin. Higher-magnification images illustrate the morphology of skin layers. Scale bars = 100 μm; scale bar in details = 25 μm. (c) Quantification of epidermal thickness relative to WT. *P < (d) Trichrome III blue staining of back skin sections and quantification of subcutaneous adipocyte layer thickness. Scale bar = 25 μm. *P < (e) Ultrastructural analysis of WT and PKP1–/– desmosomes. Scale bar = 500 nm; scale bar in details = 100 nm. (f) Quantification of desmosome number and size in WT and PKP1–/– dorsal skin. ***P < BL, basal layer; GL, granular layer; KO, knockout; n.s., not significant; PKP, plakophilin; Rel., relative; SC, stratum corneum; SL, spinous layer; WT, wild-type.
Journal of Investigative Dermatology  , DOI: ( /j.jid )
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4. Figure 3
The tight junction barrier is impaired in PKP1–/– mice. (a) Time-course analysis of weight loss in newborn WT and PKP1–/– mice. n = 8 WT mice, n = 5 knockout mice. ***P < (b) Transepidermal water loss measurements of WT and PKP1–/– mice. n = 3 WT mice, n = 5 knockout mice. **P < (c) Localization of tight junction proteins zonula occludens 1 (ZO-1), claudin 1 (CLDN-1), and occludin (OCLN) in WT and PKP1–/– skin. The left columns show tight junction proteins in red and DNA in blue, the second columns show the proteins alone. Scale bar = 25 μm. (d) Western blot analysis of tight junction proteins. A Coomassie-stained gel run in parallel shows equal loading. (e) Biotin penetration assay of newborn WT and PKP1–/– mice. Biotin is shown in green and ZO-1 in red. Scale bar = 25 μm. (f) A toluidine blue penetration assay of newborn PKP1+/+ and –/– mice. Scale bar = 1 cm. CLDN-1, claudin 1; h, hours; OCLN, occludin; PKP, plakophilin; Rel., relative; TEWL, transepidermal water loss; WT, wild-type; ZO-1, zonula occludens 1.
Journal of Investigative Dermatology  , DOI: ( /j.jid )
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5. Figure 4
PKP1–/– keratinocytes recapitulate the defects observed in PKP1–/– skin. (a) WT and PKP1–/– keratinocytes grown for 24 hours in high-calcium medium were immunostained for the indicated proteins. Scale bar = 50 μm; scale bar in details = 10 μm. (b) Western blot analysis of WT and PKP1–/– keratinocytes grown for 24 hours in high-calcium medium. α-Tubulin was used as loading control. (c) The strength of intercellular adhesion of WT versus PKP1–/– keratinocytes was assessed by dispase assays. Representative images show the integrity of the detached cell monolayer before and after application of mechanical stress (rotation). (d) Transepithelial electrical resistance measurements of WT versus PKP1–/– keratinocytes at the indicated time points after Ca2+-switch. *P < 0.05, **P < 0.005, ***P < (e) Cell counts of WT and PKP1–/– keratinocytes. *P < cad, cadherin; cat, catenin; CLDN-1, claudin 1; DSC, desmocollin; DSG, desmoglein; DSP, desmoplakin; h, hours; OCLN, occudin; p120ctn, p120 catenin; PG, plakoglobin; PKP, plakophilin; Rel., relative; TER, transepithelial electrical resistance; WT, wild-type; ZO-1, zonula occludens 1.
Journal of Investigative Dermatology  , DOI: ( /j.jid )
Copyright © 2016 The Authors Terms and Conditions