Linker for activation of T cells, zeta-associated protein-70, and Src homology 2 domain-containing leukocyte protein-76 are required for TCR-induced microtubule-organizing center polarization.
Engagement of the T cell with Ag on an APC results in a series of immediate signaling events emanating from the stimulation of the TCR. These events include the induced phosphorylation of a number of cellular proteins with a subsequent increase in intracellular calcium and the restructuring of the microtubule and actin cytoskeleton within the T cell. This restructuring of the cytoskeleton culminates in the polarization of the T cell's secretory apparatus toward the engaging APC, allowing the T cell to direct secretion of cytokines toward the appropriate APC. This polarization can be monitored by analyzing the position of the microtubule-organizing center (MTOC), as it moves toward the interface of the T cell and APC. The requirements for MTOC polarization were examined at a single-cell level by studying the interaction of a Jurkat cell line expressing a fluorescently labeled MTOC with Staphylococcal enterotoxin superantigen-bound Raji B cell line, which served as the APC. We found that repolarization of the MTOC substantially followed fluxes in calcium. We also used immobilized anti-TCR mAb and Jurkat signaling mutants, defective in TCR-induced calcium increases, to determine whether signaling components that are necessary for a calcium response also play a role in MTOC polarization. We found that zeta-associated protein-70 as well as its substrate adaptor proteins linker for activation of T cells and Src homology 2 domain-containing leukocyte protein-76 are required for MTOC polarization. Moreover, our studies revealed that a calcium-dependent event not requiring calcineurin or calcium/calmodulin-dependent kinase is required for TCR-induced polarization of the MTOC.
Kuhné
Michelle R
MR
Department of Medicine, Howard Hughes Medical Institute, Rosalind Russell Center for Medical Research in Arthritis, University of California, San Francisco, CA 94143, USA.
Lin
Joseph
J
Yablonski
Deborah
D
Mollenauer
Marianne N
MN
Ehrlich
Lauren I Richie
LI
Huppa
Johannes
J
Davis
Mark M
MM
Weiss
Arthur
A
D048868:Adaptor Proteins, Signal Transducing; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D000938:Antigen-Presenting Cells / Q000378:metabolism; D001596:Benzylamines / Q000494:pharmacology; D017252:CD3 Complex; D019703:Calcineurin / Q000502:physiology; D065095:Calcineurin Inhibitors; D002118:Calcium / Q000378:metabolism / Q000502:physiology; D020013:Calcium Signaling / Q000276:immunology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000502:physiology; D002352:Carrier Proteins / Q000502:physiology*; D016764:Cell Polarity / Q000276:immunology; D006801:Humans; D019169:Jurkat Cells; D008213:Lymphocyte Activation; D008565:Membrane Proteins; D022101:Microtubule-Organizing Center / Q000201:enzymology / Q000378:metabolism*; D010750:Phosphoproteins / Q000502:physiology*; D011505:Protein-Tyrosine Kinases / Q000502:physiology*; D011948:Receptors, Antigen, T-Cell / Q000037:antagonists & inhibitors / Q000276:immunology / Q000502:physiology*; D013449:Sulfonamides / Q000494:pharmacology; D013601:T-Lymphocytes / Q000201:enzymology / Q000276:immunology* / Q000378:metabolism*; D016559:Tacrolimus / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D051746:ZAP-70 Protein-Tyrosine Kinase; D000096926:Benzenesulfonamides
D048868:Adaptor Proteins, Signal Transducing; D000911:Antibodies, Monoclonal; D001596:Benzylamines; D017252:CD3 Complex; D019703:Calcineurin; D065095:Calcineurin Inhibitors; D002118:Calcium; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002352:Carrier Proteins; D008565:Membrane Proteins; D010750:Phosphoproteins; D011505:Protein-Tyrosine Kinases; D011948:Receptors, Antigen, T-Cell; D013449:Sulfonamides; D016559:Tacrolimus; D051746:ZAP-70 Protein-Tyrosine Kinase; C115335:CD3E protein, human; C110810:LAT protein, human; C092947:SLP-76 signal Transducing adaptor proteins; C072105:KN 93; D000096926:Benzenesulfonamides; C497261:ZAP70 protein, human