IPA3 是一种选择性的非 ATP 竞争性 PAK1 抑制剂，IC50 为 2.5 μM。

IPA-3 is a selective non-ATP competitive Pak1 inhibitor with IC50 of 2.5 μM, no inhibition to group II PAKs (PAKs 4-6).

IPA-3 is a non ATP-competitive, allosteric inhibitor of p21-activated kinase 1 (Pak1). PIR3.5 is the control compound of IPA-3. IPA-3 prevents Cdc42-stimulated Pak1 autophosphorylation on Thr423. IPA-3 also prevents sphingosine-dependent Pak1 autophosphorylation. IPA-3 does not target exposed cysteine residues on Pak1. The disulfide bond of IPA-3 is critical for inhibition of Pak1 and in vitro reduction by the reducing agent dithiothreitol (DTT) abolishes Pak1 inhibition by IPA-3. IPA-3 inhibits activation of Pak1 by diverse activators, but does not inhibit preactivated Pak1. IPA-3 inhibits PDGF-stimulated Pak activation in mouse embryonic fibroblasts. [1] IPA-3 inhibits Pak1 activation in part by binding covalently to the regulatory domain of Pak1. IPA-3 binds Pak1 covalently in a time- and temperature-dependent manner. IPA-3 prevents binding of the Pak1 activator Cdc42. IPA-3 binds directly to the Pak1 autoregulatory domain. IPA-3 reversibly inhibits PMA-induced membrane ruffling in cells. [2]

Pak1 (150 nM final) is pre-incubated with MBP (8.3 μM), indicated proteins, and IPA-3 or DMSO in Kinase buffer for 20 minutes at 4°C. Cdc42-GTPγS (3.2 μM) is then added and the reaction is pre-equilibrated 10 minutes at 30°C. Kinase reactions are started by the addition of ATP (to 30 μM) containing [32P]ATP and are incubated 10 min and analyzed by SDS-PAGE and autoradiography.

Human primary schwannoma cells are grown on 96 well plates for 2 days. Cells are left untreated or treated with 5 μM IPA-3, 20 μM IPA-3 or 20 μM PIR-3.5 for 24 hours. The MTS-solution is left on the cells for 3 hours, before the absorbance at 490 nm is measured. The experiments are conducted three times and mean and standard error of the mean is calculated with Excel.

42521-82-4

C20H14O2S2

350.45

IPA 3;IPA3

H2O:<1 mgml
DMSO:65 mg/mL (185.5 mM)
Ethanol:7 mg/mL (19.97 mM)
Powder: -20°C for 3 years
In solvent: -80°C for 2 years