MicrotubuleMicrotubules form key components of eukaryotic cell cytoskeletons and various organelles and mechanisms, including cilia, centrioles and flagella. Microtubules are constructed of a cylinder of protofilaments constituted of the protein molecule tubulin, which has binding properties and architecture that are conducive to producing the cylindrical configuration required. Generally, thirteen tubulin based filaments combine to form a microtubule.
Microtubules are protein structures that help make up the rigid internal cellular structure called the cytoskeleton. They are critical in a number of processes, including cell mobility, mitosis, cytokinesis, and vesicular transport.
Microtubules are polymers of tubulin dimmers which polymerize end to end in protofilaments that bundle in hollow cylindrical filaments, creating a fairly stiff tube. Most protofilaments are arranged in a sort of helix, creating a flexible and strong structure. They also have a particular polarity, so the two ends are positive and negative, like a battery or magnet; this enables them to stick to one another and many other structures.
Microtubule organization is controlled by centrosomes and basal bodies; the different controlling organelles are referred to as microtubule organizing centers (MTOCs). Microtubules involved in the cytoskeleton are also involved in mobility, and the cilia and flagella of eukaryotic cells are made up of microtubules.
Microtubules are altered by certain drugs; the taxane drug class used to treat cancer prevents microtubules from functioning in cell division. Colchicine has a similar effect. Motor proteins like kinesin and dynein, which transport important substances throughout the cell, use the microtubules as a sort of track.
Web Resources On Microtubule
Structure and Function of Microtubules
Assembly of microtubules
Book Resources On MicrotubuleDarwin's Black Box by Michael J. Behe
Microtubules by Hyams & Lloyd (Editors)
Microtubule Proteins by Jesus Avila
Editor(s): B. Long (partial)
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