SUMMARY PARAGRAPH for VCX1
VCX1 encodes a vacuolar H+/Ca2+ exchanger which is involved in calcium homeostasis and signal transduction. Vcx1p is responsible for restoring cytosolic Ca2+ levels in response to a brief Ca2+ burst. S. cerevisiae has three Ca2+ transporters: Vcx1p, a high capacity, low affinity vacuolar Ca2+ exchanger; Pmc1p, a high-affinity vacuolar Ca2+ ATPase; and Pmr1p, a Golgi Ca2+ ATPase (2, 1, 4).
Vcx1p and Pmc1p are involved in vacuolar Ca2+ accumulation and are both regulated by calcineurin although the mechanisms are different. Calcineurin induces expression of PMC1 and PMR1 through the action of the transcription factor Crz1p, whereas Vcx1p activity is negatively regulated by calcineurin in a Crz1p-independent mechanism (6, 7). Inhibition of Vcx1p by calcineurin is thought to be by a post-translational mechanism (1). Regulation of Vcx1p also involves Rcn1p that acts as an endogenous feedback inhibitor of calcineurin (8).
Vcx1p shares sequence similarity with mammalian and plant Ca2+ transporters (2, 9).
Last updated: 2006-11-20