Bioactive gangliosides. IV. Ganglioside GQ1b/Ca2+ dependent protein kinase activity exists in the plasma membrane fraction of neuroblastoma cell line, GOTO.

Abstract

A ganglioside-stimulated protein phosphorylation system was discovered in plasma membrane fractions of human neuroblastoma cells (GOTO). Gangliosides (GQ1b, GT1a, GT1b, GD1a, GD1b, GD3, and GM1) could stimulate this system. GQ1b showed the most effective stimulation among these gangliosides. The substrate specificity was rather broad. Not only some (de novo) proteins of the membranes but also purified histones and tubulin were phosphate-acceptable. This protein phosphorylation system specifically depended upon Ca2+ (optimum concentration: 50-100 microM). The optimum pH was 7.0-7.5. GQ1b/Ca2+ could not directly activate well known protein kinases (Ca2+/phospholipid-activated protein kinase, Ca2+/calmodulin-activated protein kinase, and cyclic nucleotide-dependent protein kinases). Furthermore, GQ1b could replace neither phospholipids nor calmodulin. Thus, an unknown, new type of protein kinase(s) may be involved in this system. Alternatively, GQ1b may activate some known protein kinase(s) in cooperation with another unknown factor which may be removed during the preparation of the partially purified known protein kinase used in this experiment.

• Authors: S Tsuji, J Nakajima, T Sasaki, Y Nagai
• Journal: Journal of biochemistry (J Biochem) Vol. 97 Issue 3 Pg. 969-72 (Mar 1985) ISSN: 0021-924X [Print] England
• PMID: 4019442 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Gangliosides
• Histones
• Tubulin
• GQ1b ganglioside
• Protein Kinases
• Calcium

Topics

• Animals
• Calcium (pharmacology)
• Cell Line
• Cell Membrane (enzymology)
• Enzyme Activation (drug effects)
• Gangliosides (pharmacology)
• Guinea Pigs
• Histones (metabolism)
• Humans
• Neuroblastoma (enzymology)
• Phosphorylation
• Protein Kinases (metabolism)
• Substrate Specificity
• Tubulin (metabolism)