Determinants of membrane sensitivity to the peptide MP-1 ( Polybia paulista )

The membrane-disrupting peptide Mastoparan-1 (MP-1), derived from the wasp Polybia paulista is known to possess antimicrobial properties, and exhibits enhanced activity against a number of cancer cell lines relative to healthy cells. Due to the mechanism of action of MP-1 it is likely that differences in plasma membrane lipid composition arising from cancer associated mutations, such as localisation of phosphatidylserine (PS) lipids to the outer leaflet of the plasma membrane, are involved in driving that enhanced activity. Rapid screening of MP-1 mutants in a combined approach using model membrane and cell-based biological assays, has led to the identification of a number of derivative peptides with enhanced selectivity for cancer-like membrane models and breast cancer cell lines and provided insights into the mechanism of membrane disruption and cell death. Notably, the morphology of the membrane perturbations observed by Atomic Force Microscopy (AFM) and activity in cell model systems can change considerably in response to single-point mutations in the MP-1 sequence, indicating a complex structure-activity relationship.