GW284543

GW284543 (CAS No.: 790186-68-4) is a small-molecule, selective inhibitor of mitogen-activated protein kinase kinase 5 (MEK5), a key upstream regulator of the ERK5 signaling pathway implicated in cellular proliferation, survival, and oncogenic signaling networks. This compound has been shown to suppress MEK5 activity, leading to a reduction in phosphorylated ERK5 (pERK5) levels and subsequent downregulation of endogenous MYC protein, thereby providing a valuable tool for investigating MEK5–ERK5-mediated compensatory mechanisms and transcriptional regulation in cancer-related and other signaling contexts. GW284543 exhibits inhibitory activity in the nanomolar to low micromolar range in biochemical and cellular assays, depending on experimental conditions, and is widely utilized in in vitro cell-based studies to dissect pathway-specific effects and signaling cross-talk. In addition, it may be applied in preclinical experimental models to explore the biological consequences of MEK5 inhibition, particularly in systems where ERK5 signaling contributes to adaptive resistance or pathway redundancy. The concentrations or dosing regimens employed vary according to the specific design and objectives of each study, making GW284543 a useful research reagent for mechanistic studies and targeted pathway interrogation in molecular and cellular biology.