Research & Innovation
Publications
HMCN1 variants aggravate epidermolysis bullosa simplex phenotype
PMU Authors
Stefan Hainzl, Thomas Kocher, Roland Zauner, Josefina Pinon Hofbauer, Verena Wally, Ulrich Koller
All Authors
Shir Bergson, Ofer Sarig, Moshe Giladi, Janan Mohamad, Mariana Mogezel-Salem, Karina Smorodinsky-Atias, Ofir Sade, Bar Manori, Sari Assaf, Kiril Malovitski, Yarden Feller, Mor Pavlovsky, Stefan Hainzl, Thomas Kocher, Julia I. Hummel, Noy Eretz Kdosha, Lubna Gazi Khair, Roland Zauner, Josefina Pinon Hofbauer, Ruby Shalom-Feuerstein, Verena Wally, Ulrich Koller, Liat Samuelov, Yoni Haitin, Uri Ashery, Rotem Rubinstein, Eli Sprecher
Journal association
Journal of experimental medicine
Abstract
Epidermolysis bullosa simplex (EBS) refers to a heterogeneous group of inherited skin disorders characterized by blister formation within the basal cell layer. The disease is characterized by marked variations in phenotype severity, suggesting co-inheritance of genetic modifiers. We identified three deleterious variants in HMCN1 that co-segregated with a more severe phenotype in a group of 20 individuals with EBS caused by mutations in KRT14, encoding keratin 14 (K14). HMCN1 codes for hemicentin-1. Protein modeling, molecular dynamics simulations, and functional experiments showed that all three HMCN1 variants disrupt protein stability. Hemicentin-1 was found to be expressed in human skin above the BMZ. Using yeast-2-hybrid, co-immunoprecipitation, and proximity ligation assays, we found that hemicentin-1 binds K14. Three-dimensional skin equivalents grown from hemicentin-1-deficient cells were found to spontaneously develop subepidermal blisters, and HMCN1 downregulation was found to reduce keratin intermediate filament formation. In conclusion, hemicentin-1 binds K14 and contributes to BMZ stability, which explains the fact that deleterious HMCN1 variants co-segregate with a more severe phenotype in KRT14-associated EBS.
Keywords
EXPRESSION, DISEASE SEVERITY, MUTATIONS, GENES, KERATIN-5, RECESSIVE DYSTROPHIC EPIDERMOLYSIS, MMP1 PROMOTER, MACULAR DEGENERATION, Digenic inheritance, Hemicentin