三量体Gタンパク質Goαの糖脂質ミクロドメイン

抄録

The association of gangliosides with specific proteins in the central nervous system was examined by co-immunoprecipitation with an anti-ganglioside antibody. The monoclonal antibody to the ganglioside GD3 immunoprecipitated the α-subunit of a heterotrimeric G protein, Go (Goα) from the rat cerebellum. Using sucrose density gradient analysis, Goα, but not Gβγ, was observed in detergent-resistant membrane (DRM) raft fractions, after the addition of GTPγS. On the other hand, both Goα and Gβγwere excluded from the DRM raft fractions in the presence of GDPβS. Only Goα was observed in the DRM fractions from the cerebellum on postnatal day 7, but not from that in adult. After pertussis toxin treatment, Goα was not observed in the DRM fractions, even from the cerebellum on postnatal day 7. These results indicate the activation-dependent translocation of Goα into the DRM rafts. Furthermore, treatment with stromal cell-derived factor-1α stimulated [₃₅S]GTPγS binding to Goα, and caused Goα translocation to the DRM fractions, leading to growth cone collapse of cerebellar granule neurons. These results demonstrate involvement of signal - dependent Goα translocation to DRM in the growth cone behavior of cerebellar granule neurons.