title: CD28 stimulation regulates its association with N-ethylmaleimide-sensitive fusion protein and other proteins involved in vesicle sorting.
abstract: CD28 delivers a co-stimulatory signal for T cell antigen receptor induced activation of T cells through a mechanism which remains mostly elusive to date. In order to try and gain insight into CD28 function, we therefore applied state-of-the-art mass spectrometric protein identification technology to the analysis of CD28 immunoprecipitates prepared from Jurkat T cells. We found that N-ethylmaleimide-sensitive fusion protein (NSF) and other proteins with sequence similarities to proteins part of or implicated in vesicular protein sorting pathways, were associated with CD28 in a CD28 stimulation-dependent manner. Furthermore, N-ethylmaleimide treatment abolished the NSF/CD28 interaction completely, and blocked CD28 association with a tyrosine phosphorylated 103 kDa protein in the activated cells. These results are suggestive of a potential model for CD28 co-stimulation regulated by an NSF-catalyzed mechanism.
authors.affiliation: Department of Molecular Biotechnology, University of Washington, Seattle, WA, USA.
authors.forename: M
authors.initials: M
authors.lastname: Heller
authors.forename: J D
authors.initials: JD
authors.lastname: Watts
authors.forename: R
authors.initials: R
authors.lastname: Aebersold
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D018106:CD28 Antigens / Q000235:genetics / Q000378:metabolism*; D005033:Ethylmaleimide / Q000494:pharmacology; D006801:Humans; D019169:Jurkat Cells; D008954:Models, Biological; D008969:Molecular Sequence Data; D020543:Proteome; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology
chemical_list: D018106:CD28 Antigens; D020543:Proteome; D011948:Receptors, Antigen, T-Cell; D011993:Recombinant Fusion Proteins; D005033:Ethylmaleimide