The calcium-dependent ATP-Mg/Pi mitochondrial carrier is a target of glucose-induced calcium signalling in Saccharomyces cerevisiae

found a clear stimulation of ATP-transport activity by calcium, with an SO 5 of approx. 30 [mu M. Our results also suggest that Sal 1p is a target of the glucose-induced calcium signal which is nonessential in wild-type cells, but becomes essential for transport of ATP into mitochondria in yeast lacking ADP/ATP translocases.Sallp is a mitochondrial protein that belongs to the SCaMC (short calcium-binding mitochondrial carrier) subfamily of mitochondrial carriers. The presence of calcium-binding motifs facing the extramitochondrial space allows the regulation of the transport activity of these carriers by cytosolic calcium and provides a new mechanism to transduce calcium signals in mitochondria without the requirement of calcium entry in the organelle. We have studied its transport activity, finding that it is a carboxyatractyloside-resistant ATP-Mg carrier. Mitochondria from a disruption mutant of SAL1 have a 50 % reduction in the uptake of ATP. We have also found a clear stimulation of ATP-transport activity by calcium, with an S-05 of approx. 30 mu M. Our results also suggest that Sal 1p is a target of the glucose-induced calcium signal which is nonessential in wild-type cells, but becomes essential for transport of ATP into mitochondria in yeast lacking ADP/ATP translocases.