||Budding yeast Saccharomyces cerevisiae
||Strayle J, Pozzan T, Rudolph HK. Steady-state free Ca(2+) in the yeast endoplasmic reticulum reaches only 10 microM and is mainly controlled by the secretory pathway pump pmr1. EMBO J. 1999 Sep 1 18(17):4733-43.PubMed ID10469652
||Researchers developed a yeast ER Ca2+ probe based on aequorin, a Ca2+ photoprotein that emits light when exposed to Ca2+ in the presence of its prosthetic group coeleterazine.
||Article describes in vivo measurements of free Ca2+ in the lumen of the yeast ER using a protein chimera which consists of the Ca2+ sensitive photoprotein aequorin fused onto Stt3, an ER resident oligosaccharyl transferase subunit. Measurements with this sensor reveal a steady state free Ca2+ level of ~10µM for the yeast ER, a concentration significantly lower than free Ca2+ in the mammalian ER. See BNID 103966, 101700