Figure 11.38. Dynamic instability of microtubules.

Figure 11.38Dynamic instability of microtubules

Dynamic instability results from the hydrolysis of GTP bound to β-tubulin during or shortly after polymerization, which reduces its binding affinity for adjacent molecules. Growth of microtubules continues as long as there is a high concentration of tubulin bound to GTP. New GTP-bound tubulin molecules are then added more rapidly than GTP is hydrolyzed, so a GTP cap is retained at the growing end. However, if GTP is hydrolyzed more rapidly than new subunits are then added, the presence of GDP-bound tubulin at the end of the microtubule leads to disassembly and shrinkage. Only the plus ends of microtubules are illustrated.

From: Microtubules

Cover of The Cell
The Cell: A Molecular Approach. 2nd edition.
Cooper GM.
Sunderland (MA): Sinauer Associates; 2000.
Copyright © 2000, Geoffrey M Cooper.

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