Shpakov A O, Pertseva M N
Laboratory of Molecular Endocrinology, I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg.
Bull Exp Biol Med. 2006 Mar;141(3):302-6. doi: 10.1007/s10517-006-0156-6.
The peptide toxin mastoparan increased GTP-binding activity of heterotrimeric G proteins in tissues of vertebrate and invertebrate animals, the effect of mastoparan in mussel tissues being less pronounced. The stimulatory effect of mastoparan on GTP binding was not observed after treatment of membranes with pertussis toxin that selectively modulates function of Gi proteins. Activity of mastoparan decreased in the presence of C-terminal peptide 346-355 from the Gi protein alphai2-subunit. Mastoparan dose-dependently decreased the stimulatory effect of hormones on GTP binding in tissues of rats and mussels. The influence of these hormones on the cell is realized via Gi proteins. However, mastoparan did not modulate the effect of Gs protein-activating hormones.
