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: Jamal-Eddine Bouameur, Bertrand Favre, Lionel Fontao, Prakash Lingasamy, Nadja Begré, Luca Borradori
• Journal: The Journal of investigative dermatology (J Invest Dermatol) Vol. 134 Issue 11 Pg. 2776-2783 (Nov 2014) ISSN: 1523-1747 [Electronic] United States
• PMID: 24940650 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Keratin-14
• Keratin-5
• Plectin
• Recombinant Proteins
• Keratins

Topics

• Binding Sites
• Cell Line, Tumor
• Epidermolysis Bullosa Simplex (immunology)
• HEK293 Cells
• Humans
• Keratin-14 (chemistry)
• Keratin-5 (chemistry)
• Keratins (chemistry)
• Muscular Dystrophies (immunology)
• Mutation
• Plectin (chemistry)
• Protein Binding
• Protein Multimerization
• Protein Structure, Quaternary
• Protein Structure, Tertiary
• Recombinant Proteins (chemistry)
• Two-Hybrid System Techniques