title: Interaction of plectin with keratins 5 and 14: dependence on several plectin domains and keratin quaternary structure.
abstract: Plectin, a cytolinker of the plakin family, anchors the intermediate filament (IF) network formed by keratins 5 and 14 (K5/K14) to hemidesmosomes, junctional adhesion complexes in basal keratinocytes. Genetic alterations of these proteins cause epidermolysis bullosa simplex (EBS) characterized by disturbed cytoarchitecture and cell fragility. The mechanisms through which mutations located after the documented plectin IF-binding site, composed of the plakin-repeat domain (PRD) B5 and the linker, as well as mutations in K5 or K14, lead to EBS remain unclear. We investigated the interaction of plectin C terminus, encompassing four domains, the PRD B5, the linker, the PRD C, and the C extremity, with K5/K14 using different approaches, including a rapid and sensitive fluorescent protein-binding assay, based on enhanced green fluorescent protein-tagged proteins (FluoBACE). Our results demonstrate that all four plectin C-terminal domains contribute to its association with K5/K14 and act synergistically to ensure efficient IF binding. The plectin C terminus predominantly interacted with the K5/K14 coil 1 domain and bound more extensively to K5/K14 filaments compared with monomeric keratins or IF assembly intermediates. These findings indicate a multimodular association of plectin with K5/K14 filaments and give insights into the molecular basis of EBS associated with pathogenic mutations in plectin, K5, or K14 genes.
authors.affiliation: Department of Dermatology, Inselspital Bern University Hospital, Bern, Switzerland; Department of Clinical Research, University of Bern, Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland.
authors.forename: Jamal-Eddine
authors.initials: JE
authors.lastname: Bouameur
authors.affiliation: Department of Dermatology, Inselspital Bern University Hospital, Bern, Switzerland; Department of Clinical Research, University of Bern, Bern, Switzerland. Electronic address: Bertrand.Favre@insel.ch.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Favre
authors.affiliation: Department of Dermatology, Geneva University Hospital, Geneva, Switzerland.
authors.forename: Lionel
authors.initials: L
authors.lastname: Fontao
authors.affiliation: Department of Dermatology, Inselspital Bern University Hospital, Bern, Switzerland; Department of Clinical Research, University of Bern, Bern, Switzerland.
authors.forename: Prakash
authors.initials: P
authors.lastname: Lingasamy
authors.affiliation: Department of Dermatology, Inselspital Bern University Hospital, Bern, Switzerland; Department of Clinical Research, University of Bern, Bern, Switzerland.
authors.forename: Nadja
authors.initials: N
authors.lastname: Begré
authors.affiliation: Department of Dermatology, Inselspital Bern University Hospital, Bern, Switzerland; Department of Clinical Research, University of Bern, Bern, Switzerland.
authors.forename: Luca
authors.initials: L
authors.lastname: Borradori
mesh_terms: D001665:Binding Sites; D045744:Cell Line, Tumor; D016110:Epidermolysis Bullosa Simplex / Q000276:immunology; D057809:HEK293 Cells; D006801:Humans; D053547:Keratin-14 / Q000737:chemistry*; D053555:Keratin-5 / Q000737:chemistry*; D007633:Keratins / Q000737:chemistry; D009136:Muscular Dystrophies / Q000276:immunology; D009154:Mutation; D051190:Plectin / Q000737:chemistry*; D011485:Protein Binding; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry; D020798:Two-Hybrid System Techniques
chemical_list: D053547:Keratin-14; D053555:Keratin-5; D051190:Plectin; D011994:Recombinant Proteins; D007633:Keratins