Ins and outs of Ca(2+) transport by acidic organelles and cell migration

Much contemporary evidence underscores the pathophysiological importance of Ca(2+) handling by acidic organelles such as lysosomes. Whereas our knowledge of how Ca(2+) is released from these acidic Ca(2+) stores (the ‘outs’) is advancing, we know relatively little about how Ca(2+) uptake is effected (the ‘ins’). Here I highlight new work identifying animal Ca(2+)/H(+) (CAX) exchangers that localize to acidic organelles, mediate Ca(2+) uptake and regulate cell migration in vivo. Continued molecular definition of the acidic Ca(2+) store toolkit provides new insight into Ca(2+)-dependent function.