p97 encodes ubiquitin-directed unfoldase Valosin-containing protein, a member of the AAA ATPase family of proteins. p97 plays a role in the ubiquitin proteasome system and has potential biomedical application in cancer therapy. MSC 1094308 is a non-competitive inhibitor of p97 with IC50 value of 7.2 μM. MSC 1094308 inhibits VPS4B about ten times more potently than p97 with IC50 value of 0.71 μM. In vitro, MSC 1094308 didn’t affect the KM or cooperativity of p97 and VPS4B, but the Vmax was progressively reduced with increasing concentrations of MSC 1094308, indicating a non-competitive inhibitory mechanism for ATPases. Incubation with 20 μM MSC 1094308 effectively inhibited D2 ATPase activity by roughly 80% in the mutant deficient in D1 hydrolysis, however, MSC 1094308 inhibited the residual D1 ATPase activity in the D2 hydrolysis mutant only by 30%, suggesting that MSC1094308 targets predominantly the D2 domain of p97. Treatment with 10 μM MSC 1094308 for 8h induced accumulation of polyubiquitinated proteins in HCT116 cells. Treatment Hela cells with 10 μM MSC 1094308 inhibited p97 without proteasomes[1].
作用机制
MSC 1094308 binds to an allosteric binding site, that located at D2 domain in the interface area between the D1 and D2 domain of p97, thereby inhibiting the D2 ATPase activity[1].
搜索
