a-factor or o-factor 17.2 The mating pathway is triggered by STE2=a-factor recepto SCG1 STE4 STEl STE3=a-factor receptor GGβG signal transduction STE20= kinase Figure 17. 4 The same mating STE11=kina se type response is triggered by interaction of either pheromone STE= kinase with its receptor. The signal iS transmitted through a series of needed ioa cell fusion ase kinases to a transcription factor KSS1=kinase es conjugation there may be branches to some of the final functions STE12=transcription factor ↓ 消当 inhibits cln2Figure 17.4 The same mating type response is triggered by interaction of either pheromone with its receptor. The signal is transmitted through a series of kinases to a transcription factor; there may be branches to some of the final functions. 17.2 The mating pathway is triggered by signal transduction