title: IL-7 induces tyrosine phosphorylation of clathrin heavy chain.
abstract: IL-7 induction of protein tyrosine phosphorylation was examined in an IL-7-dependent thymocyte cell line, D1, which was generated from a p53-/- mouse. Anti-phosphotyrosine antibody was used both to immunoprecipitate and Western blot, and showed that IL-7 induced tyrosine phosphorylation of a protein with a molecular weight of approximately 200 kDa. The P200 band was purified by reversed-phase high-performance liquid chromatography. Amino acid sequencing by mass spectrometry revealed three peptides identical to rat clathrin heavy chain (CHC) 1 (192 kDa), and this was confirmed by blotting with an anti-clathrin antibody. Stimulation of normal pro-T cells by IL-7 showed an increased tyrosine phosphorylation of clathrin heavy chain. Tyrosine phosphorylation of clathrin heavy chain was strongly induced by IL-7 and to a lesser extent by IL-4, while no effect could be observed with the cytokines IL-2, IL-9 and IL-15, whose receptors share the gammac chain. Phosphorylation of clathrin heavy chain was found to be sensitive to Jak3 inhibitors but not to Src inhibitors. Clathrin is involved in internalization of many receptors, and its phosphorylation by IL-7 stimulation may affect the internalization of the IL-7 receptor.
authors.affiliation: Laboratory of Molecular Immunoregulation, CCR, National Cancer Institute, National Institutes of Health, Room 31-71, Building 560, Frederick, MD 21702, USA.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Jiang
authors.forename: Naima
authors.initials: N
authors.lastname: Benbernou
authors.forename: Oleg
authors.initials: O
authors.lastname: Chertov
authors.forename: Annette R
authors.initials: AR
authors.lastname: Khaled
authors.forename: Joseph
authors.initials: J
authors.lastname: Wooters
authors.forename: Scott K
authors.initials: SK
authors.lastname: Durum
mesh_terms: D000818:Animals; D033922:Clathrin Heavy Chains / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015847:Interleukin-4 / Q000494:pharmacology*; D015851:Interleukin-7 / Q000494:pharmacology*; D007378:Interleukins / Q000494:pharmacology; D053616:Janus Kinase 3; D013058:Mass Spectrometry; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010766:Phosphorylation / Q000187:drug effects; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D013601:T-Lymphocytes / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics; D014443:Tyrosine / Q000378:metabolism*; D019061:src-Family Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D015851:Interleukin-7; D007378:Interleukins; C507936:Jak3 protein, rat; D016159:Tumor Suppressor Protein p53; D033922:Clathrin Heavy Chains; D015847:Interleukin-4; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; C507935:Jak3 protein, mouse; D053616:Janus Kinase 3; D019061:src-Family Kinases