Mechanism of Action
Direct G Protein Activation
Mastoparan mimics activated GPCRs by directly binding and activating Gi and Go heterotrimeric proteins, stimulating GTPase activity and releasing Gbeta-gamma subunits. This receptor-independent G protein activation allows researchers to activate downstream signaling cascades without receptor ligand complications. Mastoparan-7 is a more potent G protein activator.
Mast Cell Degranulation and Membrane Effects
Mastoparan directly stimulates mast cell degranulation via Gi protein activation, releasing histamine, serotonin, and leukotrienes independently of IgE receptor signaling. At higher concentrations, mastoparan also disrupts membranes via amphipathic helix insertion, similar to melittin.
Research Summary
G Protein Signaling Research Tool
Research ToolMastoparan is a standard pharmacological tool for attributing cellular responses to Gi/Go protein activation independently of receptor involvement. It has been used to map G protein-mediated regulation of ion channels, second messenger systems, and vesicle secretion across hundreds of research studies.
Insulin Secretion
PreclinicalMastoparan stimulates insulin release from pancreatic beta cells via Gi protein-dependent and -independent mechanisms. This has been used to study exocytosis regulation in beta cells and potential targets for insulin secretagogue development.
Antimicrobial Activity
PreclinicalMastoparan shows broad-spectrum antimicrobial activity against bacteria, fungi, and protozoa via membrane disruption. Analogs with reduced cytotoxicity and enhanced antimicrobial activity have been designed.
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Research Protocols
| Goal | Dose | Frequency | Route |
|---|---|---|---|
| G protein activation (cell signaling) | 5-50 uM | Single time-point | In vitro (cell suspension) |
| Mast cell degranulation model | 1-10 ug/mL | Single application | In vitro (mast cell culture) |
| Antimicrobial MIC | 2-64 ug/mL | Single plate read | In vitro broth microdilution |
Mastoparan is a research tool. Its hemolytic and pro-inflammatory properties preclude systemic human use.
Interactions
Safety Profile
Mastoparan is hemolytic and pro-inflammatory at systemic doses. It causes mast cell degranulation, contributing to wasp sting allergic reactions. Wasp sting anaphylaxis can be life-threatening in sensitized individuals. No human therapeutic application exists.
References
- [1]Higashijima T, et al. Mastoparan, a peptide toxin from wasp venom, mimics receptors by activating GTP-binding regulatory proteins (G proteins). J Biol Chem. 1988;263(14):6491-6494.
- [2]Mousli M, et al. Activation of rat peritoneal mast cells by substance P and mastoparan. J Pharmacol Exp Ther. 1990;254(2):393-398.
- [3]Konno K, et al. Mastoparan, a wasp venom peptide, induces mitochondria to undergo the permeability transition. J Biol Chem. 1999;274(50):36006-36012.