| Budget Amount *help |
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1988: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1987: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
A ganglioside-stimulated ecto-type protein phosphorylation system (ecto-Gg-kinase) was detected on the cell surface of a human neuroblastoma cell line (GOTO). When intact cells were incubated with r-^<32>P-ATP, at least 28 cell surface proteins were phosphorylated, as evident on SDS-PAGE (4-20 %) analysis. Exogenously added gangliosides specifically stimulated the phosphorylation of at least three cell surface associated proteins of Mr=64,000, 60,000 and 54,000. Phosphorylation was directed toward Thr and Ser residues, respectively, as revealed on acid hydrolysis followed by electrophoresis. GQ1b, at 5 nM, was the most potent among the several gangliosides tested and was more effective when added to cells before r-^<32>P-ATP administration. The simultaneous addition of an excess amount of the saccharide portion of GQ1b (oligo-GQ1b) inhibited the GQ1b-stimulated phosphorylationg indication the necessity of the sialo-saccharide moiety. These results strongly suggest that phosphorylation of the three proteins may be closely associated with the highly specific neuritogenic effect of GQ1b previously reported.
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