title: Transient tyrosine phosphorylation of human ryanodine receptor upon T cell stimulation.
abstract: The ryanodine receptor of Jurkat T lymphocytes was phosphorylated on tyrosine residues upon stimulation of the cells via the T cell receptor/CD3 complex. The tyrosine phosphorylation was transient, reaching a maximum at 2 min, and rapidly declined thereafter. In co-immunoprecipitates of the ryanodine receptor, the tyrosine kinases p56(lck) and p59(fyn) were detected. However, only p59(fyn) associated with the ryanodine receptor in a stimulation-dependent fashion. Both tyrosine kinases, recombinantly expressed as glutathione S-transferase (GST) fusion proteins, phosphorylated the immunoprecipitated ryanodine receptor in vitro. In permeabilized Jurkat T cells, GST-p59(fyn), but not GST-p56(lck), GST-Grb2, or GST alone, significantly and concentration-dependently enhanced Ca(2+) release by cyclic ADP-ribose. The tyrosine kinase inhibitor PP2 specifically blocked the effect of GST-p59(fyn). This indicates that intracellular Ca(2+) release via ryanodine receptors may be modulated by tyrosine phosphorylation during T cell activation.
authors.affiliation: Division of Cellular Signal Transduction, Institute for Medical Biochemistry and Molecular Biology, University of Hamburg, University Hospital Eppendorf, Martinistrasse 52, D-20246 Hamburg, Germany. guse@uke.uni-hamburg.de
authors.forename: A H
authors.initials: AH
authors.lastname: Guse
authors.forename: A Y
authors.initials: AY
authors.lastname: Tsygankov
authors.forename: K
authors.initials: K
authors.lastname: Weber
authors.forename: G W
authors.initials: GW
authors.lastname: Mayr
mesh_terms: D002118:Calcium / Q000378:metabolism; D006801:Humans; D019169:Jurkat Cells; D008213:Lymphocyte Activation; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / Q000502:physiology; D010766:Phosphorylation; D011518:Proto-Oncogene Proteins / Q000502:physiology; D051076:Proto-Oncogene Proteins c-fyn; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism*; D013601:T-Lymphocytes / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism*
chemical_list: D011518:Proto-Oncogene Proteins; D019837:Ryanodine Receptor Calcium Release Channel; D014443:Tyrosine; C494957:FYN protein, human; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D051076:Proto-Oncogene Proteins c-fyn; D002118:Calcium