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α cell a cell Figure A.13 Pheromones bind to receptors and activate a signal transduction pathway. Chemical signals (pheromones) released
by a and cells bind to receptors on the cell surface of cells of the opposite mating type. Once bound to the receptor, a signal is sent to
the nucleus via a signal transduction pathway and transcription of genes required for mating is turned on.
Signal Transduction Pathway Involves
G Proteins and a Protein Kinase Cascade
a cells and cells communicate with each other for the
purpose of mating through extracellular segments of the
receptors that interact directly with the appropriate mating
pheromone. Receptor segments exposed to the inside of the
cell are coupled to a membrane-bound G protein composed
of , , and subunits, encoded respectively by the SCG1,
STE4, and STE18 genes. The mating pheromones, receptors, and G proteins act in concert as a molecular switch, with the
binding of pheromone...
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- Spring '08