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Branching of keratin intermediate filaments
- Source :
- Journal of Structural Biology. 194:415-422
- Publication Year :
- 2016
- Publisher :
- Elsevier BV, 2016.
-
Abstract
- Keratin intermediate filaments (IFs) are crucial to maintain mechanical stability in epithelial cells. Since little is known about the network architecture that provides this stiffness and especially about branching properties of filaments, we addressed this question with different electron microscopic (EM) methods. Using EM tomography of high pressure frozen keratinocytes, we investigated the course of several filaments in a branching of a filament bundle. Moreover we found several putative bifurcations in individual filaments. To verify our observation we also visualized the keratin network in detergent extracted keratinocytes with scanning EM. Here bifurcations of individual filaments could unambiguously be identified additionally to bundle branchings. Interestingly, identical filament bifurcations were also found in purified keratin 8/18 filaments expressed in Escherichia coli which were reassembled in vitro. This excludes that an accessory protein contributes to the branch formation. Measurements of the filament cross sectional areas showed various ratios between the three bifurcation arms. This demonstrates that intermediate filament furcation is very different from actin furcation where an entire new filament is attached to an existing filament. Instead, the architecture of intermediate filament bifurcations is less predetermined and hence consistent with the general concept of IF formation.
- Subjects :
- Keratinocytes
0301 basic medicine
Electron Microscope Tomography
Intermediate Filaments
macromolecular substances
Branching (polymer chemistry)
Cell Line
Protein filament
03 medical and health sciences
Structural Biology
Keratin
Escherichia coli
medicine
Humans
Intermediate filament
Actin
chemistry.chemical_classification
Anatomy
030104 developmental biology
medicine.anatomical_structure
chemistry
Electron tomography
Microscopy, Electron, Scanning
Keratin 8
Biophysics
Keratins
Keratinocyte
Subjects
Details
- ISSN :
- 10478477
- Volume :
- 194
- Database :
- OpenAIRE
- Journal :
- Journal of Structural Biology
- Accession number :
- edsair.doi.dedup.....4eb97d0a2c6331c4e5caffa3e67a228d