Abstract 1278 A role of YDL206W in regulating intracellular calcium signaling in Saccharomyces cerevisiae

Cytosolic calcium ions play an important role in regulating intracellular signaling pathways. Sodium calcium exchanger (NCX) is a key player in the homeostasis of cytosolic calcium in myocardial cells and neuron cells. Mis-regulation of NCX can lead to abnormal calcium influx and cause diseases that include optical nerve injury, neuronal apoptosis, and Alzheimer's disease. Thus, the identification of novel NCX and understanding of its mechanism may contribute to revealing the mechanism of NCX-related diseases. Yeast is a widely used model organism for studying calcium signaling. However, NCX has not been identified in yeast. Interestingly, bioinformatics analysis suggests that YDL206W, an uncharacterized gene in yeast, may encode a sodium calcium exchanger. We find that disrupting the YDL206W gene in yeast diminished the level of calcium-induced activation of calcineurin, which suggests that YDL206w is required for proper calcium signaling. Confocal microscopy analysis shows that Ydl206w is localized in the endoplasmic reticulum and Golgi. Together, our results reveal YDL206W as a new regulator for calcineurin signaling in yeast and suggest a role of the endoplasmic reticulum and Golgi in regulating cytosolic calcium in yeast. We greatly acknowledge Dr. Renata Anita Tisi at University of Milano-Bicocca, Milan, Italy for providing the aequorin reporter; the confocal microscopy images were taken using the confocal microscope funded by NSF and were under the supervision of Wendy Teal; the work was partially funded by a grant from the National Institutes of Health.