Targeted proteolysis of plectin isoform 1a accounts for hemidesmosome dysfunction in mice mimicking the dominant skin blistering disease EBS-Ogna

Gernot Walko, Nevena Vukasinovic, Karin Gross, Irmgard Fischer, Sabrina Sibitz, Peter Fuchs, Siegfried Reipert, Ute Jungwirth, Walter Berger, Ulrich Salzer, Oliviero Carugo, Maria J Castañón, Gerhard Wiche

Research output: Contribution to journalArticlepeer-review

40 Citations (Scopus)

Abstract

Autosomal recessive mutations in the cytolinker protein plectin account for the multisystem disorders epidermolysis bullosa simplex (EBS) associated with muscular dystrophy (EBS-MD), pyloric atresia (EBS-PA), and congenital myasthenia (EBS-CMS). In contrast, a dominant missense mutation leads to the disease EBS-Ogna, manifesting exclusively as skin fragility. We have exploited this trait to study the molecular basis of hemidesmosome failure in EBS-Ogna and to reveal the contribution of plectin to hemidesmosome homeostasis. We generated EBS-Ogna knock-in mice mimicking the human phenotype and show that blistering reflects insufficient protein levels of the hemidesmosome-associated plectin isoform 1a. We found that plectin 1a, in contrast to plectin 1c, the major isoform expressed in epidermal keratinocytes, is proteolytically degraded, supporting the notion that degradation of hemidesmosome-anchored plectin is spatially controlled. Using recombinant proteins, we show that the mutation renders plectin's 190-nm-long coiled-coil rod domain more vulnerable to cleavage by calpains and other proteases activated in the epidermis but not in skeletal muscle. Accordingly, treatment of cultured EBS-Ogna keratinocytes as well as of EBS-Ogna mouse skin with calpain inhibitors resulted in increased plectin 1a protein expression levels. Moreover, we report that plectin's rod domain forms dimeric structures that can further associate laterally into remarkably stable (paracrystalline) polymers. We propose focal self-association of plectin molecules as a novel mechanism contributing to hemidesmosome homeostasis and stabilization.

Original languageEnglish
Pages (from-to)e1002396
JournalPlos Genetics
Volume7
Issue number12
DOIs
Publication statusPublished - Dec 2011

Keywords

  • Animals
  • Blister/genetics
  • Calpain/antagonists & inhibitors
  • Dipeptides/pharmacology
  • Disease Models, Animal
  • Epidermis/cytology
  • Epidermolysis Bullosa Simplex/genetics
  • Gene Expression
  • Gene Knock-In Techniques
  • Hemidesmosomes/chemistry
  • Keratinocytes/metabolism
  • Mice
  • Muscle Cells/cytology
  • Mutation, Missense/genetics
  • Plectin/chemistry
  • Protein Isoforms/genetics
  • Proteolysis
  • Recombinant Proteins/genetics

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