Mas7, a structural analogue of mastoparan, is an activator of heterotrimeric Gi proteins and its downstream effectors.
Mas7 produces several biological effects in different cell types. The effect of Mas7 on endogenous mono-ADP-ribosyltransferase activity is in the micromolar range with a maximal activation of 205% over the basal. In pertussis treated plasma membranes, it is found that the effect of Mas7 on endogenous mono-ADP-ribosyltransferase is partially blocked, which suggests the involvement of G-proteins, such as Gi or G0[1]. Mas7 is a basic tetradecapeptide isolated from isp venom, which activates guanine nucleotide-binding regulatory proteins (G-proteins) and stimulates apoptosis. In smooth muscle cells, Mas7 leads to an increase in the perfusion pressure. Vascular contraction is induced by Mas7. The vasoconstriction triggered by mas-7 exhibited a slower increase compared to that simulated by phenylephrine or vasopressin[2]. Exposure of hippocampal neurons to a low dose of Mas-7 increases dendritic spine density and spine head width in a time-dependent manner. Additionally, Mas-7 enhances postsynaptic density protein-95 (PSD-95) clustering in neurites and activates Gαo signaling, increasing the intracellular Ca2+ concentration[3].
[1]. Bavec A, et al. Novel features of amphiphilic peptide Mas7 in signalling via heterotrimeric G-proteins. J Pept Sci. 2004 Nov;10(11):691-9. [2]. Grze•k G, et al. Direct regulation of vascular smooth muscle contraction by mastoparan-7. Biomed Rep. 2014 Jan;2(1):34-38. [3]. RamÍrez VT, et al. The Gαo Activator Mastoparan-7 Promotes Dendritic Spine Formation in Hippocampal Neurons. Neural Plast. 2016;2016:4258171.