First published online September 20, 2006
Journal of Cell Science 119, 1905e (2006)
© The Company of Biologists Limited
Axonal polarity - GSK-3ß in AKTivated
The establishment of axonal polarity is an important event in development of the nervous system. Some of the molecules involved in this process have been identified but we know little about how they control polarity. On p. 3927, Annette Gärtner, Xu Huang and Alan Hall report that GSK-3ß, a kinase involved in numerous signalling pathways, regulates the process but does so through a novel mechanism. Previous studies had suggested that GSK-3ß is specifically inactivated at the growing tips of axons through phosphorylation by another signalling kinase, Akt/PKB, and that this could drive establishment of polarity. Now, Hall and co-workers have examined the establishment of polarity in hippocampal neurons taken from mice in which both isoforms of GSK-3ß are replaced by non-phosphorylatable mutants. They find that these neurons develop a single axon just like wild-type neurons. However, pharmacological inhibition of GSK-3ß leads to symmetric outgrowth of multiple axon-like processes and changes in the direction of vesicle trafficking. The authors therefore conclude that GSK-3ß inhibition is important for the establishment of neuronal polarity but is not initiated by phosphorylation by Akt/PKB.
Related articles in JCS:
- Neuronal polarity is regulated by glycogen synthase kinase-3 (GSK-3ß) independently of Akt/PKB serine phosphorylation
- Annette Gärtner, Xu Huang, and Alan Hall
JCS 2006 119: 3927-3934.
[Abstract]
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