Chemotaxis in reverse

A cell polarity switch controls whether cells rush toward an attractive chemical or shift into reverse when they encounter something repulsive, according to Keizer-Gunnink et al. on page 579. They show that the status of phospholipase C (PLC) sets up the polarity axis for directional movement.

As professional crawlers, Dictyostelium cells had previously revealed that chemoattractants cause a PIP3 build-up on that side of the cell, which in turn induces the actomyosin motility machinery. Now, the authors show that the same crawlers hold the keys to chemorepulsion.

When faced with a repellent, the cells built up PIP3 on the opposite side of the cell, inducing the motility machinery to reverse direction. Attractants and repellents caused PIP3 levels to rise on opposite...