tailieunhanh - Báo cáo Y học: Interactions between the Fyn SH3-domain and adaptor protein Cbp/PAG derived ligands, effects on kinase activity and affinity

Csk-binding protein⁄phosphoprotein associated with glycosphingolipid-enriched domains is a transmembrane adaptor protein primarily involved in negative regulation of T-cell activation by recruitment of C-terminal Src kinase (Csk), a protein tyrosine kinase which represses Src kinase activity through C-terminal phosphorylation. Recruitment of Csk occurs via SH2-domain binding to PAG pTyr317, thus, the interaction is highly dependent on phosphorylation performed by the Src family kinase Fyn, which docks onto PAG using a dual-domain binding mode involving both SH3- and SH2-domains of Fyn | ỊFEBS Journal Interactions between the Fyn SH3-domain and adaptor protein Cbp PAG derived ligands effects on kinase activity and affinity o i I i Ạ Qnlhnim1 2 p nnnnlin PoýqqIqI ĩ3 Anno I R i-ilxlxo1 2 R Piok1 R RI iccolI3 kfift iI Tnn1 2 Silje A. oolllcllll cvangelia rcloalakl Anne J. OtUkka nuueil D. Russell IXjeiil laokcll and Torunn Derge1 2 1 The Biotechnology Centre of Oslo Norway 2 Centre for Molecular Medicine Norway Nordic EMBL Partnership University of Oslo Norway 3 European Molecular Biology Laboratory Heidelberg Germany Keywords kinase activity proline-rich motifs proteinprotein interactions SH3 domain tyrosine phosphorylation Correspondence T. Berge The Biotechnology Centre of Oslo Gaustadalleen 21 N-0319 Oslo Norway Fax 47 2284 0501 Tel 47 2284 0519 E-mail Website http Received 8 May 2008 revised 24 June 2008 accepted 4 August 2008 doi Csk-binding protein phosphoprotein associated with glycosphingolipid-enriched domains is a transmembrane adaptor protein primarily involved in negative regulation of T-cell activation by recruitment of C-terminal Src kinase Csk a protein tyrosine kinase which represses Src kinase activity through C-terminal phosphorylation. Recruitment of Csk occurs via SH2-domain binding to PAG pTyr317 thus the interaction is highly dependent on phosphorylation performed by the Src family kinase Fyn which docks onto PAG using a dual-domain binding mode involving both SH3- and SH2-domains of Fyn. In this study we investigated Fyn SH3-domain binding to 14-mer peptide ligands derived from Cbp PAG-enriched microdomains sequence using biochemical biophysical and computational techniques. Interaction kinetics and dissociation constants for the various ligands were determined by SPR. The local structural impact of ligand association has been evaluated using CD and molecular modelling has been employed to investigate details of the interactions. We show that data .