Table of Contents

Cytoskeleton

The cytoskeleton is a network of fibers composed of proteins contained within a cell's cytoplasm. Although the name implies the cytoskeleton is stable, it is a dynamic structure, parts of which are constantly destroyed, renewed, or newly constructed.


Cytoskeletal protein.

Cytoskeleton Classification

The cytoskeleton is divided into three main types of filaments based on their size, protein composition, and function. A fourth group, septins, is emerging as a potential cytoskeletal element.

~~CLOSE~~ Microfilaments (Actin Filaments)

~~CLOSE~~ Intermediate Filaments

~~CLOSE~~ Microtubules

~~CLOSE~~ Septins (Emerging Group)

Summary Table

Component Diameter Protein(s) Polarity Main Functions
Microfilaments ~7 nm Actin Yes Shape, motility, endocytosis, cytokinesis
Intermediate Filaments ~10 nm Keratin, vimentin, etc. No Mechanical support, nuclear structure
Microtubules ~25 nm α/β-tubulin Yes Transport, division, cilia/flagella, polarity
Septins (optional) ~10 nm Septins (GTP-binding) Suggested Cytokinesis, polarity, scaffolding