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Molecular architecture of intermediate filaments
Sergei V Strelkov1, Harald Herrmann, Ueli Aebi
1Maurice E. Müller Institute for Structural Biology, Biozentrum Basel, Switzerland.
Summary
Intermediate filaments (IFs) are crucial for cell function but their structure is poorly understood. New X-ray data on vimentin dimers may allow detailed molecular modeling of IFs.
Area of Science:
- Cell Biology
- Structural Biology
- Biochemistry
Background:
- Intermediate filaments (IFs) are a key component of the cellular cytoskeleton, alongside microtubules and actin microfilaments.
- IFs play critical roles in cell division, motility, and overall cellular integrity in metazoan organisms.
- Unlike microtubules and microfilaments, the atomic-level architecture of IFs remains largely undetermined.
Purpose of the Study:
- To investigate the molecular structure of intermediate filaments (IFs).
- To understand the assembly process of cytoplasmic IF proteins like vimentin.
- To enable the development of detailed molecular models of IFs based on recent structural data.
Main Methods:
- Analysis of X-ray crystallographic data for fragments of the vimentin dimer.
- Characterization of the elementary building block of IFs: the alpha-helical coiled-coil dimer.
- Modeling of tetramer and filament structures based on dimer data.
Main Results:
- Recent X-ray crystallographic data provide high-resolution structural information for vimentin dimer fragments.
- The elementary IF building block is an elongated, rod-like dimer with an alpha-helical coiled-coil structure.
- Assembly pathways for cytoplasmic IFs (vimentin) and nuclear lamins differ in their initial steps.
Conclusions:
- The obtained structural data for vimentin dimers are foundational for creating accurate molecular models of tetramers and filaments.
- Improved understanding of IF architecture will elucidate their role in cellular processes.
- This work paves the way for detailed structural studies of the entire intermediate filament network.