Mastoparan as a G Protein Activator

Mastoparan was isolated from the venom of wasp, Vespula lewisii, as a peptide that induces histamine release from rat peritoneal mast cells (Hirai et al., 1979). It is a C-terminally amidated tetradecapeptide comprising primarily basic and hydrophobic amino acid residues but no acidic residues (Tab. 1). Structurally similar peptides that also induce the histamine release have been isolated from venom of other wasps and hornets, and are collectively termed mastoparans (Nakajima et al., 1985). Mastoparans were also found to induce exocytosis from a variety of cells: serotonin from platelets (Ozaki et al., 1990), insulin from pancreatic β cells (Yokokawa et al., 1989), surfactant from pulmonary alveolar type 2 epithelial cells (Joyce-Brady et al., 1991), and catecholamine from chromaffin cells (Kuroda et al., 1980; Vitale et al., 1993). This peptide also elevates intracellular Ca2+ concentration in neutrophils (Perianin and Snyderman, 1989) and promotes proliferation of Swiss 3T3 cells (Gil et al., 1991). Table 1 Primary structure of mastoparan and its derivatives. Peptide Primary structurea Commercial sourceb notes mastoparan Ile Asn Leu Lys Ala Leu Ala Ala Leu Ala LysLyslIe Leu NH2 1,2,3,4,5,6 c Mas7 Iie Asn Leu LysAla Leu Ala Ala Leu Ala Lys Ala Leu Leu NH2 1,2,3,4 d Mas8 Iie Asn Leu LysAla Leu Ala Ala Leu Ala Lys Arg Leu Leu NH2 1,3 d Mas11 Iie Asn Leu LysAla Leu Ala Ala Leu Ala Lys Ala Leu Leu NH2 none d Mas17 Ile Asn Leu Lys Ala Ala Ala Leu Ala Lys Lys Leu Leu NH2 1,2,3,4 d a Amino acid residues that differ from those of mastoparan are shown underlined. b Commercial source: 1, Peninsula Laboratories; 2, Bachem; 3, Phoenix Pharmaceuticals; 4, Biomolecular Research Laboratories; 5, Peptide Institute; 6, Sigma. cfrom (Hirai et al., 1979) dfrom (Higashijima et al., 1990)