Amplification and propagation of pacemaker Ca2+ signals by cyclic ADP-ribose and the type 3 ryanodine receptor in T cells.
Ligation of the T-cell receptor/CD3 complex results in global Ca(2+) signals that are essential for T-cell activation. We have recently reported that these global Ca(2+) signals are preceded by localized pacemaker Ca(2+) signals. Here, we demonstrate for the first time for human T cells that an increase in signal frequency of subcellular pacemaker Ca(2+) signals at sites close to the plasma membrane, in the cytosol and in the nucleus depends on the type 3 ryanodine receptor (RyR) and its modulation by cyclic ADP-ribose. The spatial distribution of D-myo-inositol 1,4,5-trisphosphate receptors and RyRs indicates a concerted action of both of these receptors/Ca(2+) channels in the generation of initial pacemaker signals localized close to the plasma membrane. Inhibition or knockdown of RyRs resulted in significant decreases in (1) the frequency of initial pacemaker signals localized close to the plasma membrane, and (2) the frequency of localized pacemaker Ca(2+) signals in the inner cytosol. Moreover, upon microinjection of cyclic ADP-ribose or upon extracellular addition of its novel membrane-permeant mimic N-1-ethoxymethyl-substituted cyclic inosine diphosphoribose, similarly decreased Ca(2+) signals were observed in both type 3 RyR-knockdown cells and in control cells microinjected with the RyR antagonist Ruthenium Red. Taken together, our results show that, under physiological conditions in human T cells, RyRs play crucial roles in the local amplification and the spatiotemporal development of subcellular Ca(2+) pacemaker signals.
Kunerth
Svenja
S
University Hospital Hamburg-Eppendorf, Center for Experimental Medicine, Institute of Biochemistry and Molecular Biology I: Cellular Signal Transduction, Martinistr. 52, 20246 Hamburg, Germany.
Langhorst
Matthias F
MF
Schwarzmann
Nadine
N
Gu
Xianfeng
X
Huang
Lijun
L
Yang
Zhenjun
Z
Zhang
Liangren
L
Mills
Steven J
SJ
Zhang
Li-He
LH
Potter
Barry V L
BV
Guse
Andreas H
AH
D001683:Biological Clocks; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D020013:Calcium Signaling; D002462:Cell Membrane / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D036563:Cyclic ADP-Ribose / Q000378:metabolism*; D006801:Humans; D053496:Inositol 1,4,5-Trisphosphate Receptors; D019169:Jurkat Cells; D017260:Receptor-CD3 Complex, Antigen, T-Cell / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012430:Ruthenium Red / Q000494:pharmacology; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism*; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000378:metabolism*; D013997:Time Factors
D015220:Calcium Channels; C506926:ITPR1 protein, human; D053496:Inositol 1,4,5-Trisphosphate Receptors; D017260:Receptor-CD3 Complex, Antigen, T-Cell; D018160:Receptors, Cytoplasmic and Nuclear; D019837:Ryanodine Receptor Calcium Release Channel; D012430:Ruthenium Red; D036563:Cyclic ADP-Ribose; D002118:Calcium