Fuc-GM1 ganglioside mimics the receptor function of GM1 for cholera toxin

M. Masserini, E. Freire, P. Palestini, E. Calappi, G. Tettamanti

Research output: Contribution to journalArticle

Abstract

The ability of Fuc-GM1 ganglioside to mimic the receptor function of GM1 for cholera toxin (CT) has been investigated. For this purpose, rat glioma C6 cultured cells were enriched with Fuc-GM1 and the responsiveness to CT was compared with that of cells enriched with GM1 ganglioside. Fuc-GM1 was taken up by cells as rapidly and to the same extent as GM1. When comparable amounts of ganglioside were associated, the cells enriched with Fuc-GM1 bound the same amount of 125I-CT as did cells enriched with GM1. Under conditions in which GM1- and Fuc-GM1-enriched cells bound comparable amounts of CT, the Fuc-GMl-treated cells accumulated virtually the same amount of cyclic AMP as did GM1-treated cells, and activation of adenylate cyclase was also similar. The lag time preceding the CT-induced cAMP accumulation was the same in Fuc-GM1- and GM1-enriched cells. High-sensitivity isothermal titration calorimetry (ITC) experiments showed that the association constants of CT with Fuc-GMl or GM1 ganglioside were comparable (4 × 107 M-1 and 1.9 × 107 M-1, respectively, at 25 °C). Also, the association constants of the B-subunit pentamer with Fuc-GMl or GM1 ganglioside were comparable (about 3 × 107 M-1 and 7 × 107 M-1, respectively, at 25 °C).

Original languageEnglish
Pages (from-to)2422-2426
Number of pages5
JournalBiochemistry
Volume31
Issue number8
Publication statusPublished - 1992

ASJC Scopus subject areas

  • Biochemistry

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    Masserini, M., Freire, E., Palestini, P., Calappi, E., & Tettamanti, G. (1992). Fuc-GM1 ganglioside mimics the receptor function of GM1 for cholera toxin. Biochemistry, 31(8), 2422-2426.