Calcineurin-dependent growth control in Saccharomyces cerevisiae mutants lacking PMC1, a homolog of plasma membrane Ca2+ ATPases

Abstract

Ca 2÷ signaling plays an important role in the activation of T cells (Gardner, 1989). Binding of antigens to specific receptors at the surface of quiescent T cells triggers the opening of Ca 2÷ channels in the endoplasmic reticulum and plasma membrane, leading to rapid elevation in [Ca2÷]c.

Elevated cytosolic free Ca2+ concentrations and massive Ca2+ accumulation within vacuoles, in yeast mutant lacking PMR1, a homolog of Ca2+‐ATPase

“…Mut~ nts lacking vacuolar H+-ATPase activity cannot grow in h gh Ca 2* medium and show marked increase in [Ca2*]i levels ben exposed to moderate [Ca2+]out [11,26]. The high levels of vacuoles [9]. A second putative Ca 2+ transporter may be present in the ER membrane.…”

“…Genetic data have strongly suggested a role of Pmrlp in maintaining the homeostasis of cytosolic free Ca 2+ concentration ([Ca2+]i): overexpression of Pmrlp suppresses defects associated with loss of vacuolar Ca z+ pump Pmclp. Non-viable pmrl pmcl double mutants become viable upon mutation in calcineurin [9,10]. However, a direct evaluation of the role of Pmrlp in [Ca2+]i homeostasis, by measurments of [Ca2+]i levels in pmrl mutants exposed to a range of external Ca 2+ concentrations, has not as yet been reported.…”

A calmodulin‐stimulated Ca2+‐ATPase from plant vacuolar membranes with a putative regulatory domain at its N‐terminus1

“…This would imply the presence of at least two Ca2+ -transport systems in this membrane: one is the BCAI Ca2+ -ATPase, and the other is a Ca 2 +/H+ antiporter [25]. Similarly, yeast vacuolar membranes contain a Ca 2 +-ATPase (Pmc1p) as well as a Ca 2 +/H+ antiporter (Vcxlp), both of which are characterized at the molecular level [26,27]. Thermodynamic considerations argue that Ca 2 +-ATPases are necessary to account for the extremely low concentrations of Ca2+ in the cytosol [28].…”

An Osmotically Induced Cytosolic Ca2+ Transient Activates Calcineurin Signaling to Mediate Ion Homeostasis and Salt Tolerance of Saccharomyces cerevisiae

“…Measurement of 45 Ca 2ϩ Accumulation-Procedures for determining Ca 2ϩ uptake into cells were as described, with modifications (17,28). Cells in the exponential growth phase (YPD medium) were inoculated into fresh medium (OD 600 ϳ0.1) that contained 1 Ci/ml of 45 Ca 2ϩ ( 45 CaCl 2 , ICN Biomedicals Inc., Costa Mesa, CA).…”

“…The Hal4p/Hal5p signal pathway also activates the Trk1-Trk2 transport system high affinity transition, although the post-translational process has not been defined nor is it known whether Ca 2ϩ is required for the function of this pathway (16). Calcineurin post-transcriptionally regulates Vcx1p, which together with Pmc1p and Pmr1p function to evacuate Ca 2ϩ from the cytosol (17,18).…”