Mitotic and pheromone-specific intrinsic polarization cues interfere with gradient sensing in Saccharomyces cerevisiae

Many cell types can find their ways in the environment following gradients of external signaling molecules either by migrating (chemotaxis) or growing (chemotropism) toward the source of the signal. In both cases, the proteins that control cytoskeleton dynamics concentrate, by an autocatalytic mechanism, in the membrane facing the uphill direction of the gradient. Because this polarization is self-amplifying, gradient sensing is susceptible to mistakes, especially because cells have intrinsic polarity cues that can compete with external gradients. Here, we show that, in budding yeast, the presence of internal cues used to guide patterns of division can interfere with the ability to track sexual-pheromone gradients used to find mating partners.