Generation of cell polarity in plants links endocytosis, auxin distribution and cell fate decisions

The polar transport of the plant hormone auxin is dependent on the localization of its efflux carriers called PINs, but the mechanism mediating polarity of PIN proteins within cells remains unclear. This study suggests a two-step mechanism generating PIN polarity. PINs are first targeted to the plasma membrane in a non-polar manner, and polarity is established in subsequent step involving internalization and recycling. Interference with endocytosis results in the loss of PIN polarity leading to a perturbation in auxin gradients.