Background:

IPA-3 is an autoregulatory domain inhibitor of p21-activated kinase (Pak) with IC50 value of 2.5μM [1].

IPA-3 is a highly selective and non-ATP-competitive inhibitor that targets the autoregulatory mechanism of group I Paks. IPA-3 is screened out as an inhibitor of Pak1 by measuring ATP hydrolysis. In the in vitro assays, IPA-3 inhibits Pak1 autophosphorylation stimulated by Cdc42 or sphingosine. It shows an IC50 value of 2.5μM in the kinase assay. This inhibition of Pak1 is reported to be noncompetitive with ATP. Besides that, IPA-3 is found to remarkably inhibit the kinase activity of other group I Pak members, Pak2 and 3 at concentration of 10μM. Furthermore, 30μM IPA-3 can prevent both basal and PDGF-stimulated Pak activities in mouse embryonic fibroblasts [1].

参考文献:
[1] Deacon S W, Beeser A, Fukui J A, et al. An isoform-selective, small-molecule inhibitor targets the autoregulatory mechanism of p21-activated kinase. Chemistry & biology, 2008, 15(4): 322-331.