Mechanism of intermediate filament recognition by plakin repeat domains revealed by envoplakin targeting of vimentin

• Published in: Nature communications Vol. 7; no. 1; p. 10827
• Main Authors: Fogl, Claudia, Mohammed, Fiyaz, Al-Jassar, Caezar, Jeeves, Mark, Knowles, Timothy J., Rodriguez-Zamora, Penelope, White, Scott A., Odintsova, Elena, Overduin, Michael, Chidgey, Martyn
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 03-03-2016; Nature Publishing Group; Nature Portfolio
• Subjects: 101/6; 13/106; 13/109; 631/45/612/1228; 631/57/2272; 631/80/128/1580; 82/103; Amino Acid Motifs; Animals; Cloning, Molecular; Escherichia coli - metabolism; Humanities and Social Sciences; Humans; Intermediate Filaments - chemistry; Intermediate Filaments - metabolism; Membrane Proteins - chemistry; Membrane Proteins - metabolism; Models, Molecular; multidisciplinary; Phylogeny; Protein Binding; Protein Conformation; Protein Precursors - chemistry; Protein Precursors - metabolism; Science; Science (multidisciplinary); Vimentin - chemistry; Vimentin - metabolism
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms10827

Plakin proteins form critical connections between cell junctions and the cytoskeleton; their disruption within epithelial and cardiac muscle cells cause skin-blistering diseases and cardiomyopathies. Envoplakin has a single plakin repeat domain (PRD) which recognizes intermediate filaments through an unresolved mechanism. Herein we report the crystal structure of envoplakin’s complete PRD fold, revealing binding determinants within its electropositive binding groove. Four of its five internal repeats recognize negatively charged patches within vimentin via five basic determinants that are identified by nuclear magnetic resonance spectroscopy. Mutations of the Lys1901 or Arg1914 binding determinants delocalize heterodimeric envoplakin from intracellular vimentin and keratin filaments in cultured cells. Recognition of vimentin is abolished when its residues Asp112 or Asp119 are mutated. The latter slot intermediate filament rods into basic PRD domain grooves through electrosteric complementarity in a widely applicable mechanism. Together this reveals how plakin family members form dynamic linkages with cytoskeletal frameworks.
Plakin proteins link cell junctions to cytoskeletal frameworks, and their disruption within epithelial and cardiac muscle cells cause skin blistering diseases and cardiomyopathies. Here the authors use structural biology approaches to reveal the mechanism that allows plakins to recognize intermediate filaments within the cytoskeleton.