S. Maekawa et al., Localization of neuronal growth-associated, microtubule-destabilizing factor SCG10 in brain-derived raft membrane microdomains, J BIOCHEM, 129(5), 2001, pp. 691-697
Raft is a mobile membrane subdomain enriched in sphingolipid and cholestero
l and also various signaling molecules. Previous observation suggested that
brain-derived rafts contain tubulin but that rafts of non-neural origin do
not. We hypothesized that SCG10, one of the neuronal growth-associated pro
teins (nGAPs), might be a neuron-specific molecule that anchors tubulin. to
neuronal rafts, and we explored biochemically its subcellular localization
, interaction with tubulin, and effects on microtubule dynamics. In postnat
al rat brain extracts, SCG10 was recovered mostly in membrane-associated fr
actions, and at least half was included in the raft fraction that was also
enriched in GAP-43 and NAP-22. SCG10-enriched brain rafts also contained tu
bulin, and chemical cross-linking experiments revealed that SCG10 was close
ly associated with tubulin, In addition, SCG10 was able to inhibit polymeri
zation of tubulin, These results indicate that SCG10 is a component of neur
onal rafts as are other nGAPs, and suggest that SCG10 may be involved in si
gnaling events in membranes for cytoskeletal reorganization around neuronal
rafts.