Re-establishment of PIN2 polarity after cell division (Nature Plants)

Plant cells have polarity, with the distribution of the auxin transporter protein PIN2 being a well-described example. Glanc et al. investigated how polarity is re-established following cell division. The authors showed that during cytokinesis, protein trafficking is directed towards the central cell plate (site of the new cell wall), but afterwards PIN2 relocalizes to its proper apical position. Using a variety of manipulations and mutants, they investigated several hypothesis as to how polarity is re-established, and found that the positional information seems to be cell-intrinsic. That is, rather than the daughter cell learning which way is up from its neighbors or some other external polarity  (such as auxin), the information appears to be learned from the mother cell. The authors also show that endocytosis is needed for PIN2 repolarization, as is a PINOID-related protein kinase. (Summary by Mary Williams) Nature Plants 10.1038/s41477-018-0318-3