Gangliosides inhibit the phosphorylation of both small and large rat myelin basic proteins (SMBP, LMBP) by an endogenous phospholipid‐sensitive Ca2+‐dependent protein kinase (C‐Kinase). Using a rat brain myelin preparation in an in vitro phosphorylation assay system, we determined the inhibition constants (IC50's) of the gangliosides GM1, GD1a, GD1b, and GT1b to be approximately 160 μM, 65 μM, 65 μM, and 40 μM, respectively. Asialoganglioside GA1, ceramide, and Nacetylneuraminic acid (NANA, sialic acid) failed to produce similar inhibition, suggesting that both the lipid and the sialic acid moieties are necessary, but neither alone is sufficient to produce inhibition. The results indicate that gangliosides may regulate protein kinase C activities in the nervous system.
- myelin basic protein
- phospholipid‐sensitive Ca‐dependent protein kinase
- protein C‐kinase
ASJC Scopus subject areas
- Cellular and Molecular Neuroscience