Study of the Interactions Between Mitogen-Activated Protein Kinases and Small Molecule Inhibitors of Substrate Proteins Using Fluorescence Spectroscopy

Abstract

The extracellular-signal-regulated kinase (ERK) proteins belong to the mitogen-activated protein kinase (MAPK) family. In addition to participating in important cell signaling pathways involved in normal cellular functions, unregulated activation of the ERK pathway promotes the proliferation and survival of cancer cells. As such, targeted inhibition of the ERK pathway is a goal in the development of new anti-cancer drugs. Given the importance of the ERK pathway in regulating normal cellular processes, we sought to identify small molecules that can selectively inhibit ERK interactions with protein substrates that promote cancer cell proliferation, but preserve ERK functions in normal cells. To accomplish this, computer-aided drug design (CADD) was used to identify low molecular weight compounds that are predicted to interact with specific substrate docking sites on ERK2. In addition, chemical modifications were made to explore structure-activity relationships. The results of the studies demonstrate how steady-state fluorescence spectroscopy methods can be used to rapidly identify ERK-targeted compounds, determine binding affinities, and evaluate the specificity for the ERK proteins as compared to the structurally related MAPK proteins.