Multimeric CAX complexes and Ca2+ signaling – Beyond humdrum housekeeping

Abstract

Vacuolar Ca2+/H+ antiporters (CAXs) contribute to Ca2+ homeostasis within plant cells. But do they do more? Arabidopsis CAX isoforms have heretofore not been known to act in concert, but Hocking et al. (2017) now present a plethora of evidence suggesting that this underlies plasticity in response to environmental cues. CAX1 and CAX3 may form heteromeric transporters that impact guard cell function/leaf gas exchange, and leaf (mesophyll) cell responses to biotic stress.