title: Actin cytoskeleton regulates calcium dynamics and NFAT nuclear duration.
abstract: T-cell activation by antigen-presenting cells is accompanied by actin polymerization, T-cell receptor (TCR) capping, and formation of the immunological synapse. However, whether actin-dependent events are required for T-cell function is poorly understood. Herein, we provide evidence for an unexpected negative regulatory role of the actin cytoskeleton on TCR-induced cytokine production. Disruption of actin polymerization resulted in prolonged intracellular calcium elevation in response to anti-CD3, thapsigargin, or phorbol myristate acetate plus ionomycin, leading to persistent NFAT (nuclear factor of activated T cells) nuclear duration. These events were dominant, as the net effect of actin blockade was augmented interleukin 2 promoter activity. Increased surface expression of the plasma membrane Ca(2+) ATPase was observed upon stimulation, which was inhibited by cytochalasin D, suggesting that actin polymerization contributes to calcium export. Our results imply a novel role for the actin cytoskeleton in modulating the duration of Ca(2+)-NFAT signaling and indicate that actin dynamics regulate features of T-cell activation downstream of receptor clustering.
authors.affiliation: Department of Pathology, The University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: Fabiola V
authors.initials: FV
authors.lastname: Rivas
authors.forename: James P
authors.initials: JP
authors.lastname: O'Keefe
authors.forename: Maria-Luisa
authors.initials: ML
authors.lastname: Alegre
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Gajewski
mesh_terms: D000199:Actins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D027682:Cation Transport Proteins; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism*; D015638:Cytochalasin D / Q000494:pharmacology; D016207:Cytokines / Q000235:genetics; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D007376:Interleukin-2 / Q000235:genetics; D017136:Ion Transport / Q000187:drug effects; D051379:Mice; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D053499:Plasma Membrane Calcium-Transporting ATPases; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism*; D018417:Th1 Cells / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D018418:Th2 Cells / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D000199:Actins; D027682:Cation Transport Proteins; D016207:Cytokines; D004268:DNA-Binding Proteins; D007376:Interleukin-2; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D011948:Receptors, Antigen, T-Cell; D014157:Transcription Factors; D015638:Cytochalasin D; D038362:Glycogen Synthase Kinase 3; D053499:Plasma Membrane Calcium-Transporting ATPases; D000252:Calcium-Transporting ATPases; D002118:Calcium