MG-115 (Z-Leu-Leu-Nva-H) is a potent, reversible peptide aldehyde inhibitor of proteasome chymotrypsin-like and caspase-like activities. It induces p53 dependent apoptosis. Blockade of proteasomal degradation by MG115 can activate autophagy.
Treatment with proteasome inhibitors Z-Leu-Leu-Nva-H (MG-115) or Z-Leu-Leu-Leu-H (MG-132) prevented the accelerated degradation of these mutant receptors, resulting in increased amounts of the mutant receptors in the COS-7 cells [1].
A potent, reversible proteasome inhibitor with Ki of 21 nM for 20S proteasome and 35 nM for 26S proteasome. The inhibition of proteasome was through specific inhibition of chymotrypsin-like activity of the proteasome. Also shown to induce apoptosis in Rat-1 and PC12 cells via a p3-independent pathway.
References:
1. Involvement of heat shock protein 90 in the degradation of mutant insulin receptors by the proteasome. Imamura, T., Haruta, T., Takata, Y., Usui, I., Iwata, M., Ishihara, H., Ishiki, M., Ishibashi, O., Ueno, E., Sasaoka, T., Kobayashi, M. J. Biol. Chem. (1998)