Published 26 November 2001. doi:10.1083/jcb1555iti5
© The Rockefeller University Press,
0021-9525/2001/11/690-a $5.00
The Journal of Cell Biology, Volume 155, Number 5, November 26, 2001 690-a-691
Ankyrin recruits a fleet
| |
Ankyrin-G (green) helps cluster ßIV spectrin (red) and others.
|
|
Axon initial segments are specialized microdomains that integrate neuronal inputs and initiate action potentials. On page 739, Jenkins and Bennett demonstrate that the ankyrin-G adaptor protein is required to coordinate the assembly of the initial segment during early development, and suggest that related mechanisms may regulate the assembly of other microdomains in a variety of cell types.Concentrated in axon initial segments are both voltage-gated sodium channels and several proteins that have been hypothesized to direct the assembly of the microdomain. In the new work, the authors examined protein localization in Purkinje neuron initial segments during development in wild-type and ankyrin-G mutant mice. Ankyrin-G and ßIV spectrin appear at axon initial segments by postnatal day 2, but the sodium channels and adhesion molecules are not fully assembled in the microdomain until seven days later. In mice lacking cerebellar ankyrin-G, ßIV spectrin and other components of the microdomain fail to cluster in the axon initial segments.
The results imply that ankyrin-G directs the assembly of voltage-gated sodium channels, ßIV spectrin, and adhesion molecules in the axon initial segment to form this critical microdomain. The presence of ankyrin-G in other microdomains, such as neuromuscular junctions and the basolateral domains of epithelial cells, suggests that it may function similarly elsewhere. 
Alan W. Dove
alanwdove{at}earthlink.net
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Facebook 
Reddit 
Technorati 
Twitter What's this?
