Src family tyrosine kinase Lyn binds several proteins including paxillin in rat basophilic leukemia cells

Autor: H. Nishikata, K Minoguchi, Reuben P. Siraganian, H Kihara, Majed M. Hamawy
Rok vydání: 1994
Předmět:
Zdroj: Molecular Immunology. 31:519-529
ISSN: 0161-5890
DOI: 10.1016/0161-5890(94)90039-6
Popis: Aggregation of the high affinity IgE receptors on rat basophilic leukemia (RBL-2H3) cells results in protein tyrosine phosphorylation although the receptor has no intrinsic enzymatic activity. The Src related protein tyrosine kinase p 53 56 lyn present in RBL-2H3 cells could play a role in this reaction. Here we have isolated the cDNA for rat Lyn and found it to be very homologous at the amino acid level to both the human and mouse proteins. A bacterially expressed maltose binding protein-Lyn (MBP-Lyn) fusion protein was already tyrosine phosphorylated and had tyrosine kinase activity. In a filter-binding assay, MBP-Lyn fusion protein (at 0.1 μM) specifically bound to several proteins of RBL-2H3 cells. In lysates of IgE receptor-activated cells, there was increased binding of MBP-Lyn to 65, 72, 78 and 110 kDa tyrosine phosphorylated proteins. The 72, 78 and 110 kDa tyrosine phosphorylated proteins were precipitated by a fusion protein containing the Lyn Src Homology 2 (SH2) domain. The 72 kDa Lyn binding protein was different from p72 syk . Furthermore, paxillin, a cytoskeletal protein, was identified as one of the Lyn binding proteins. Thus Fcϵ RI mediated signal transduction in RBL-2H3 cells may result from the interaction of p 53 56 lyn with paxillin, pp72, pp110 and other proteins.
Databáze: OpenAIRE