title: Gelsolin overexpression alters actin dynamics and tyrosine phosphorylation of lipid raft-associated proteins in Jurkat T cells.
abstract: Upon T cell receptor engagement, both the actin cytoskeleton and substrates of tyrosine phosphorylation are remodeled to create a signaling complex at the interface of the antigen-presenting cell and responding T cell. While T cell signaling has been shown to regulate actin reorganization, the mechanisms by which changes in actin dynamics affect early T cell signaling have not been fully explored. Using gelsolin, an actin-binding protein with capping and severing activities, and latrunculin, an actin-depolymerizing agent, we have further investigated the interplay between actin dynamics and the regulation of T cell signaling. Overexpression of gelsolin altered actin dynamics in Jurkat T cells, and alteration of actin dynamics correlated with dysregulation of tyrosine phosphorylation of raft-associated substrates. This perturbation of tyrosine phosphorylation was correlated with inhibition of activation-dependent signaling pathways regulating Erk-1/2 phosphorylation, NF-AT transcriptional activation and IL-2 production. Modification of actin by the depolymerizing agent latrunculin also altered the tyrosine phosphorylation patterns of proteins associated with lipid rafts, and pre-treatment with latrunculin inhibited anti-CD3 mAb-mediated NF-AT activation. Thus, our data indicate that actin cytoskeletal dynamics modulate the tyrosine phosphorylation of raft-associated proteins and subsequent downstream signal transduction.
authors.affiliation: Laboratory of Lymphocyte Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA. morley_c@kids.wustl.edu
authors.forename: S Celeste
authors.initials: SC
authors.lastname: Morley
authors.forename: Janice
authors.initials: J
authors.lastname: Sung
authors.forename: Guang-Ping
authors.initials: GP
authors.lastname: Sun
authors.forename: Maria Paola
authors.initials: MP
authors.lastname: Martelli
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Bunnell
authors.forename: Barbara E
authors.initials: BE
authors.lastname: Bierer
mesh_terms: D000199:Actins / Q000378:metabolism*; D000911:Antibodies, Monoclonal / Q000276:immunology; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D017252:CD3 Complex / Q000276:immunology; D003599:Cytoskeleton / Q000187:drug effects; D003902:Detergents / Q000494:pharmacology; D018260:Gelsolin / Q000235:genetics*; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis; D019169:Jurkat Cells; D021962:Membrane Microdomains / Q000187:drug effects / Q000378:metabolism*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D050778:NFATC Transcription Factors / Q000378:metabolism; D009363:Neoplasm Proteins / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D019000:Phosphotyrosine / Q000378:metabolism*; D012995:Solubility / Q000187:drug effects; D013379:Substrate Specificity / Q000187:drug effects; D013601:T-Lymphocytes / Q000276:immunology*; D053778:Thiazolidines / Q000494:pharmacology; D015533:Transcriptional Activation / Q000187:drug effects
chemical_list: D000199:Actins; D000911:Antibodies, Monoclonal; D019086:Bridged Bicyclo Compounds, Heterocyclic; D017252:CD3 Complex; D003902:Detergents; D018260:Gelsolin; D007376:Interleukin-2; D050778:NFATC Transcription Factors; D009363:Neoplasm Proteins; D053778:Thiazolidines; D019000:Phosphotyrosine; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; C037068:latrunculin B