The association of endogenous G with the purified ω-conotoxin GVIA receptor

Maureen W. McEnery, Adele M. Snowman, Solomon H. Snyder

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23 Scopus citations


Modulation of the neuronal ω-conotoxin GVIA-sensitive N-type voltage-dependent calcium channel (VDCC) by neurotransmitters and guanine nucleotides suggests a dynamic interaction between activated G-protein α subunits and the N-type VDCC. Our previous report on the purification of the N-type VDCC (McEnery, M. W., Snowman, A. M., Sharp, A. H., Adams, M. E., and Snyder, S. H. (1991) Proc. Natl. Acad. Sci. U. S. A. 88, 11095-11099), has led us to investigate a possible association of CTXR with an endogenous Gα subunit. The addition of the G-protein activator AlF4- modulated the 125I-CTX binding characteristics of the solubilized CTXR. Further immunological analyses employing Gα subunit-specific antibodies to monitor the cofractionation of Gα with 125I-CTX binding activity throughout the purification procedure indicate the selective recovery of G in the purified CTXR preparation, as neither G, G, nor Gβγ could be detected. Furthermore, G associated with CTXR acted as a substrate for pertussis toxin-dependent ADP-ribosylation only upon the addition of exogenous Gβγ subunits. These results strongly indicate a high affinity complex between an activated G and CTXR maintained throughout biochemical purification of the 125I-CTX receptor.

Original languageEnglish (US)
Pages (from-to)5-8
Number of pages4
JournalJournal of Biological Chemistry
Issue number1
StatePublished - Jan 7 1994

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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