Plant cell growth regulation Piezo sensors in animal cells are localized in the cell membrane and transduce mechanical signals. The cell membrane of plant cells, unlike that of animal cells, is usually plastered up against a stiff cell wall and does not have much mobility. Much of the cell’s volume is accounted for by a large central vacuole, the membrane of which, the tonoplast, is not so mechanically constrained. Radin et al . studied how and where plant cells use Piezo sensors. Plant homologs of the animal mechanosensitive channels are found not in the plasma membrane but rather in the tonoplast. In both moss and the small flowering plant Arabidopsis , mutations in plant Piezo sensors altered vacuolar morphology and growth patterns in tip-growing cells. —PJH