Fig. 2

Zymogen-locked matriptase is biologically active when expressed in basal keratinocytes of transgenic mice. Matriptase protein expression in the skin of newborn wildtype mice (WT) (a), keratin-5-matriptase zymogen-locked transgenic mice (b), keratin-5-matriptase catalytically inactive mice (c), matriptase null mice (d), adult wildtype mice (e), keratin-5-matriptase zymogen-locked transgenic mice (f), and keratin-5-matriptase catalytically inactive transgenic mice (g). Scale bar = 50 μm, representative for a–g. h–j Outward appearance (top panels) and histological appearance (bottom panels, h and e) of 1-year-old wildtype (h), keratin-5-matriptase zymogen-locked (i), and keratin-5-matriptase catalytically inactive (j) mice. Scale bar = 500 μm, representative for h–j. k Quantification of number of hair follicles/mm in full skin sections stained with hematoxylin and eosin from wildtype (WT, n = 4 mice), keratin-5-matriptase zymogen-locked transgenic (K5R614Q, n = 6 mice), and keratin-5-matriptase catalytically inactive transgenic (K5S805A, n = 7 mice) mice (mean ± SD). Expression of zymogen-locked matriptase, but not catalytically inactive matriptase in basal keratinocytes causes alopecia (top panels) associated with reduced hair follicle density. Additional file 1: Raw supporting data