title: CIN85 interacting proteins in B cells-specific role for SHIP-1.
abstract: The Cbl-interacting 85-kDa protein (CIN85) plays an important role as a negative regulator of signaling pathways induced by receptor tyrosine kinases. By assembling multiprotein complexes this versatile adaptor enhances receptor tyrosine kinase-activated clathrin-mediated endocytosis and reduces phosphatidylinositol-3-kinase-induced phosphatidylinositol-3,4,5-trisphosphate production. Here we report the expression of CIN85 in primary splenic B lymphocytes and the B-lymphoma cell lines WEHI 231 and Ba/F3. Cross-linking of the B cell antigen receptor resulted in an increased association of CIN85 with the ubiquitin ligase Cbl. Through a systematic pull-down proteomics approach we identified 51 proteins that interact with CIN85 in B cells, including proteins not shown previously to be CIN85-associated. Among these proteins, the SH2-containing inositol phosphatase 1 (SHIP-1) co-precipitated with both the full-length CIN85 and each of its three SH3 domains. We also showed that this association is constitutive and depends on a region of 79 amino acids near the carboxyl terminus of SHIP-1, a region rich in potential SH3 domain binding sites. Because SHIP-1 is a major negative regulator of the phosphatidylinositol-3-kinase pathway in lymphocytes, we hypothesize that the interaction between SHIP-1 and CIN85 might synergistically facilitate the down-regulation of phosphatidylinositol-3,4,5-trisphosphate levels.
authors: Institute of Medical Biochemistry and Molecular Biology, Medical Faculty, University of Rostock, Schillingallee 70, 18057 Rostock, Germany. tom.buechse@med.uni-rostock.de
authors: Tom
authors: T
authors: Büchse
authors: Nikolaus
authors: N
authors: Horras
authors: Eva
authors: E
authors: Lenfert
authors: Gerald
authors: G
authors: Krystal
authors: Sandra
authors: S
authors: Körbel
authors: Michael
authors: M
authors: Schümann
authors: Eberhard
authors: E
authors: Krause
authors: Stefan
authors: S
authors: Mikkat
authors: Markus
authors: M
authors: Tiedge
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001402:B-Lymphocytes / Q000378:metabolism; D001665:Binding Sites; D045744:Cell Line, Tumor; D005786:Gene Expression Regulation; D006801:Humans; D000072181:Inositol Polyphosphate 5-Phosphatases; D019169:Jurkat Cells; D008297:Male; D013058:Mass Spectrometry; D051379:Mice; D008810:Mice, Inbred C57BL; D046912:Multiprotein Complexes / Q000378:metabolism; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D058539:Phosphatidylinositol 3-Kinase / Q000378:metabolism*; D018129:Phosphatidylinositol Phosphates / Q000737:chemistry / Q000378:metabolism*; D000072183:Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D040901:Proteomics; D050721:Proto-Oncogene Proteins c-cbl / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction; D013154:Spleen / Q000166:cytology; D018909:src Homology Domains
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D046912:Multiprotein Complexes; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D018129:Phosphatidylinositol Phosphates; D011994:Recombinant Proteins; C498782:Sh3kbp1 protein, mouse; C060974:phosphatidylinositol 3,4,5-triphosphate; D050721:Proto-Oncogene Proteins c-cbl; D058539:Phosphatidylinositol 3-Kinase; D010744:Phosphoric Monoester Hydrolases; D000072181:Inositol Polyphosphate 5-Phosphatases; C000606430:INPP5D protein, human; C000606433:Inpp5d protein, mouse; D000072183:Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases