Pheromone-responsive transcription factor (Ste12)

Pheromone-responsive transcription factors are specialized proteins found in fungi and bacteria that orchestrate gene expression changes in response to extracellular signaling peptides or pheromones. In fungi such as Saccharomyces cerevisiae and pathogenic Candida species, the protein Ste12 (or its homolog Cph1) is the terminal effector of a G protein-coupled receptor (GPCR) and mitogen-activated protein kinase (MAPK) signaling cascade. It regulates cellular differentiation, including mating and filamentation (invasive growth), which is a key virulence factor in fungal pathogenesis. In Gram-positive bacteria, members of the RRNPP family, such as PrgX and Rgg, function as cytoplasmic pheromone receptors and transcription factors that directly bind imported quorum-sensing peptides. These bacterial factors control the expression of genes involved in conjugative plasmid transfer, biofilm development, and the production of toxins. Because these transcription factors are essential for the virulence of many pathogens and lack direct human orthologs, they are considered high-value targets for the development of next-generation anti-infective and anti-virulence therapeutics. Notably, research has shown that the cyclic peptide cyclosporin A and its non-immunosuppressive analog valspodar can potently inhibit the activation of certain bacterial pheromone-responsive transcription factors, suggesting a viable chemical scaffold for drug development.

Other names

Ste12Sterile 12Ste12pCph1PrgXRggSteARNPP family transcription factor

Competitive inhibition of pheromone or autoinducer peptide binding to the transcription factor, which prevents its activation or dissociation from DNA, thereby attenuating the expression of genes required for virulence and biofilm formation.