Keeping the vimentin network under control: cell-matrix adhesion-associated plectin 1f affects cell shape and polarity of fibroblasts

• Published in: Molecular biology of the cell 2010-10, Vol.21 (19), p.3362-3375
• Main Authors: Burgstaller, Gerald, Gregor, Martin, Winter, Lilli, Wiche, Gerhard
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Cell Adhesion; Cell Polarity; Cell Shape; Cells, Cultured; Exons - genetics; Extracellular Matrix - metabolism; Fibroblasts - cytology; Fibroblasts - metabolism; Focal Adhesions - metabolism; Intermediate Filaments - metabolism; Mice; Models, Biological; Plectin - chemistry; Plectin - metabolism; Protein Isoforms - metabolism; Protein Structure, Tertiary; Protein Transport; Recombinant Fusion Proteins - metabolism; Stress Fibers - metabolism; Time Factors; Vimentin - metabolism
• ISSN: 1059-1524; 1939-4586
• DOI: 10.1091/mbc.e10-02-0094

Focal adhesions (FAs) located at the ends of actin/myosin-containing contractile stress fibers form tight connections between fibroblasts and their underlying extracellular matrix. We show here that mature FAs and their derivative fibronectin fibril-aligned fibrillar adhesions (FbAs) serve as docking sites for vimentin intermediate filaments (IFs) in a plectin isoform 1f (P1f)-dependent manner. Time-lapse video microscopy revealed that FA-associated P1f captures mobile vimentin filament precursors, which then serve as seeds for de novo IF network formation via end-to-end fusion with other mobile precursors. As a consequence of IF association, the turnover of FAs is reduced. P1f-mediated IF network formation at FbAs creates a resilient cage-like core structure that encases and positions the nucleus while being stably connected to the exterior of the cell. We show that the formation of this structure affects cell shape with consequences for cell polarization.