KUS121 is a valosin-containing protein (VCP) modulator that inhibits VCP ATPase activity (IC50= 330 nM).1It inhibits cell death, ATP depletion, and upregulation of C/EBP-homologous protein (CHOP) induced by tunicamycin, an inducer of ER stress, in HeLa cells when used at concentrations of 20, 50, and 50 μM, respectively. KUS121 (100 μM) inhibits ATP depletion and cell death induced by oxygen-glucose deprivation (OGD) in rat primary cortical neurons in anin vitromodel of cerebral ischemia.2It reduces infarction volume and increases the latency to fall in an accelerating rotarod test in a mouse model of focal cerebral ischemia induced by transient distal middle cerebral artery occlusion (MCAO) when administered at a dose of 100 mg/kg immediately following occlusion and again at 50 mg/kg following reperfusion. KUS121 (50 mg/kg) inhibits thinning of the retinal outer nuclear layer and preserves visual function in an rd10 mouse model of retinitis pigmentosa.1