title: Frontrunners of T cell activation: Initial, localized Ca2+ signals mediated by NAADP and the type 1 ryanodine receptor.
abstract: The activation of T cells is the fundamental on switch for the adaptive immune system. Ca(2+) signaling is essential for T cell activation and starts as initial, short-lived, localized Ca(2+) signals. The second messenger nicotinic acid adenine dinucleotide phosphate (NAADP) forms rapidly upon T cell activation and stimulates early Ca(2+) signaling. We developed a high-resolution imaging technique using multiple fluorescent Ca(2+) indicator dyes to characterize these early signaling events and investigate the channels involved in NAADP-dependent Ca(2+) signals. In the first seconds of activation of either primary murine T cells or human Jurkat cells with beads coated with an antibody against CD3, we detected Ca(2+) signals with diameters close to the limit of detection and that were close to the activation site at the plasma membrane. In Jurkat cells in which the ryanodine receptor (RyR) was knocked down or in primary T cells from RyR1(-/-) mice, either these early Ca(2+) signals were not detected or the number of signals was markedly reduced. Local Ca(2+) signals observed within 20 ms upon microinjection of Jurkat cells with NAADP were also sensitive to RyR knockdown. In contrast, TRPM2 (transient receptor potential channel, subtype melastatin 2), a potential NAADP target channel, was not required for the formation of initial Ca(2+) signals in primary T cells. Thus, through our high-resolution imaging method, we characterized early Ca(2+) release events in T cells and obtained evidence for the involvement of RyR and NAADP in such signals.
authors.affiliation: The Calcium Signalling Group, Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Insa M A
authors.initials: IM
authors.lastname: Wolf
authors.affiliation: The Calcium Signalling Group, Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Björn-Philipp
authors.initials: BP
authors.lastname: Diercks
authors.affiliation: The Calcium Signalling Group, Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Ellen
authors.initials: E
authors.lastname: Gattkowski
authors.affiliation: The Calcium Signalling Group, Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Frederik
authors.initials: F
authors.lastname: Czarniak
authors.affiliation: The Calcium Signalling Group, Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Kempski
authors.affiliation: Department of Computational Neuroscience, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: René
authors.initials: R
authors.lastname: Werner
authors.affiliation: Department of Computational Neuroscience, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Schetelig
authors.affiliation: Department of Immunology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Hans-Willi
authors.initials: HW
authors.lastname: Mittrücker
authors.affiliation: Department of Immunology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Valéa
authors.initials: V
authors.lastname: Schumacher
authors.affiliation: Institute for Multiple Sclerosis Research, Department of Neuroimmunology, Gemeinnützige Hertie-Stiftung and University Medical Center Göttingen, Waldweg 33, 37073 Göttingen, Germany. Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Straße 3, 37075 Göttingen, Germany.
authors.forename: Manuel
authors.initials: M
authors.lastname: von Osten
authors.affiliation: Institute for Multiple Sclerosis Research, Department of Neuroimmunology, Gemeinnützige Hertie-Stiftung and University Medical Center Göttingen, Waldweg 33, 37073 Göttingen, Germany. Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Straße 3, 37075 Göttingen, Germany.
authors.forename: Dimitri
authors.initials: D
authors.lastname: Lodygin
authors.affiliation: Institute for Multiple Sclerosis Research, Department of Neuroimmunology, Gemeinnützige Hertie-Stiftung and University Medical Center Göttingen, Waldweg 33, 37073 Göttingen, Germany. Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Straße 3, 37075 Göttingen, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Flügel
authors.affiliation: The Calcium Signalling Group, Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Fliegert
authors.affiliation: The Calcium Signalling Group, Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany. guse@uke.de.
authors.forename: Andreas H
authors.initials: AH
authors.lastname: Guse
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry; D000818:Animals; D001572:Benzofurans / Q000737:chemistry; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling; D002478:Cells, Cultured; D005470:Fluorometry / Q000379:methods; D006801:Humans; D007093:Imidazoles / Q000737:chemistry; D019169:Jurkat Cells; D008213:Lymphocyte Activation / Q000187:drug effects; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008856:Microscopy, Fluorescence; D016853:Muromonab-CD3 / Q000494:pharmacology; D009249:NADP / Q000031:analogs & derivatives* / Q000378:metabolism; D019837:Ryanodine Receptor Calcium Release Channel / Q000235:genetics / Q000378:metabolism*; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D050053:TRPM Cation Channels / Q000378:metabolism; D013997:Time Factors; D014966:Xanthenes / Q000737:chemistry
chemical_list: D000814:Aniline Compounds; D001572:Benzofurans; C409648:Fluo 4; D007093:Imidazoles; D016853:Muromonab-CD3; D019837:Ryanodine Receptor Calcium Release Channel; D050053:TRPM Cation Channels; D014966:Xanthenes; C082877:fura red; D009249:NADP; C024376:NAADP; D002118:Calcium