SP90

SP90 is a novel, target-selective modulator of ERK1/2 signaling designed to inhibit airway smooth muscle (ASM) cell proliferation associated with chronic asthma and airway remodeling. Unlike traditional ATP-competitive ERK inhibitors, SP90 binds to the FRS (substrate-binding domain) of ERK2. This selective binding modulates the interaction with and activation of the transcription factor Activator Protein-1 (AP-1). Specifically, SP90 downregulates the expression of AP-1 components FRA-1 and FosB, as well as the downstream cell cycle regulator Cyclin D1, without exerting the broad cytotoxicity or global pathway inhibition seen with non-selective inhibitors. It was developed through computational approaches by researchers at the University of Maryland and Thomas Jefferson University.