Ca(2+) signals in Pmr1-GFP-expressing COS-1 cells with functional endoplasmic reticulum.
We studied the role of the Pmr1-containing Ca(2+) store in COS-1 cells endowed with a functional endoplasmic reticulum. Transfected cells could be recognized by using a green-fluorescent-protein (GFP)-tagged form of Pmr1. Pmr1-GFP fluorescence showed a typical juxtanuclear Golgi-like distribution. Pmr1-GFP-containing cells with functional endoplasmic reticulum responded to 100 microM ATP with baseline Ca(2+) spiking, while non-transfected cells produced an initial Ca(2+) peak followed by a long-lasting plateau. The Ca(2+) signal often appeared after a long latency in Pmr1-GFP-expressing cells. ATP-stimulated Pmr1-GFP-expressing cells with functional endoplasmic reticulum responded after a latency period to extracellular Ca(2+) with a regenerative Ca(2+) signal, while non-transfected control cells responded with an immediate slow rise in free cytosolic Ca(2+) concentration. These results demonstrate the importance of the Pmr1-containing Ca(2+) store in generating or modifying cellular Ca(2+) signals.
Missiaen
Ludwig
L
Laboratorium voor Fysiologie, K.U. Leuven Campus Gasthuisberg, Herestraat 49, Leuven B-3000, Belgium. ludwig.missiaen@med.kuleuven.ac.be
Vanoevelen
Jo
J
Van Acker
Kristel
K
Raeymaekers
Luc
L
Parys
Jan B
JB
Callewaert
Geert
G
Wuytack
Frank
F
De Smedt
Humbert
H
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D019556:COS Cells; D017173:Caenorhabditis elegans; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000502:physiology*; D000252:Calcium-Transporting ATPases / Q000235:genetics*; D003600:Cytosol / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005110:Extracellular Space / Q000378:metabolism; D049452:Green Fluorescent Proteins; D006801:Humans; D008164:Luminescent Proteins / Q000235:genetics*; D018832:Molecular Chaperones / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D013997:Time Factors; D014162:Transfection
D008164:Luminescent Proteins; D018832:Molecular Chaperones; D011993:Recombinant Fusion Proteins; C101767:SSC1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins; D000255:Adenosine Triphosphate; D000252:Calcium-Transporting ATPases; D002118:Calcium