Glycogen synthase kinase-3β (GSK-3β), governs axon and dendrite growth in determining cell polarity, according to research groups from China and Japan. GSK-3β is found throughout neurons but is less active in axonal regions, the researchers found.
Scientists at Shanghai Institutes for Biological Sciences and Beijing's National Institute of Biological Sciences created constitutively active GSK-3β mutant rat hippocampal neurons, which formed fewer axons but showed no difference in dendrite numbers.1 Inhibiting GSK-3β in normal hippocampal cells resulted in multiple axons and fewer dendrites, confirming that "the level of GSK-3 activity is critical," says coauthor Yi Rao, now at Northwestern University. His group also identified two upstream proteins: PTEN, a lipid and protein phosphatase, regulates Atk, an axon-localized kinase. Atk in turn regulates GSK-3β.
Kozo Kaibuchi and colleagues at Nagoya University and Hiroshima University in Japan report that GSK-3β controls axon/dendrite growth by regulating a protein, collapsing response mediator protein-2 (CRMP-2), which ...
