Yeast calcineurin regulates nuclear localization of the Crz1p transcription factor through dephosphorylation.

Calcineurin, a Ca2+/calmodulin dependent protein phosphatase, regulates Ca2+-dependent processes in a wide variety of cells. In the yeast, Saccharomyces cerevisiae, calcineurin effects Ca2+-dependent changes in gene expression through regulation of the Crz1p transcription factor. We show here that calcineurin dephosphorylates Crz1p and that this results in translocation of Crz1p to the nucleus. We identify a region of Crz1p that is required for calcineurin-dependent regulation of its phosphorylation, localization, and activity, and show that this region has significant sequence simlarity to a portion of NF-AT, a family of mammalian transcription factors whose localization is also regulated by calcineurin. Thus, the mechanism of Ca2+/calcineurin-dependent signaling shows remarkable conservation between yeast and mammalian cells.