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Abstract

Saccharomyces cerevisiae yeast cells court each other by producing an attractive sex pheromone specific to their mating type. Cells detect the sex pheromone from potential mates using a well-defined intracellular signalling cascade that has become a model for studying signal transduction. In contrast, the factors contributing to the production of pheromone itself are poorly characterized, despite the widespread use of the S. cerevisiae a-pheromone secretion pathway in industrial fungal protein expression systems. Progress in understanding pheromone secretion has been hindered by a lack of a precise and quantitative pheromone production assay. Here, we present an ELISA-based method for the quantification of a-pheromone secretion. In the absence of pheromone from the opposite mating type, we found that each cell secretes over 550 mature apheromone peptides per second; 90% of this total was produced from MFa1. The addition of a-pheromone more than doubled total a-pheromone secretion. This technique offers several improvements on current methods for measuring a-pheromone production and will allow detailed investigation of the factors regulating pheromone production in yeast.