A function for tyrosine phosphorylation of type 1 inositol 1,4,5-trisphosphate receptor in lymphocyte activation.
Sustained elevation of intracellular calcium by Ca2+ release-activated Ca2+ channels is required for lymphocyte activation. Sustained Ca2+ entry requires endoplasmic reticulum (ER) Ca2+ depletion and prolonged activation of inositol 1,4,5-trisphosphate receptor (IP(3)R)/Ca2+ release channels. However, a major isoform in lymphocyte ER, IP3R1, is inhibited by elevated levels of cytosolic Ca2+, and the mechanism that enables the prolonged activation of IP(3)R1 required for lymphocyte activation is unclear. We show that IP(3)R1 binds to the scaffolding protein linker of activated T cells and colocalizes with the T cell receptor during activation, resulting in persistent phosphorylation of IP(3)R1 at Tyr353. This phosphorylation increases the sensitivity of the channel to activation by IP(3) and renders the channel less sensitive to Ca2+ -induced inactivation. Expression of a mutant IP3R1-Y353F channel in lymphocytes causes defective Ca2+ signaling and decreased nuclear factor of activated T cells activation. Thus, tyrosine phosphorylation of IP3R1-Y353 may have an important function in maintaining elevated cytosolic Ca2+ levels during lymphocyte activation.
Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA.
Nikhil
N
deSouza
Jie
J
Cui
Miroslav
M
Dura
Thomas V
TV
McDonald
Andrew R
AR
Marks
D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D002645:Chickens; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000378:metabolism*; D015640:Ion Channel Gating / Q000187:drug effects; D019169:Jurkat Cells; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology*; D021962:Membrane Microdomains / Q000187:drug effects / Q000378:metabolism; D050778:NFATC Transcription Factors / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D019000:Phosphotyrosine / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology* / Q000187:drug effects / Q000276:immunology*
C506926:ITPR1 protein, human; D053496:Inositol 1,4,5-Trisphosphate Receptors; D050778:NFATC Transcription Factors; D011948:Receptors, Antigen, T-Cell; D019000:Phosphotyrosine; D015544:Inositol 1,4,5-Trisphosphate; D002118:Calcium