tailieunhanh - Báo cáo khoa học: Identification of mitogen-activated protein⁄extracellular signal-responsive kinase kinase 2 as a novel partner of the scaffolding protein human homolog of disc-large

Human disc-large homolog (hDlg), also known as synapse-associated protein 97, is a scaffold protein, a member of the membrane-associated guanylate kinase family, implicated in neuronal synapses and epithelial– epithelial cell junctions whose expression and function remains poorly char-acterized in most tissues, particularly in the vasculature. | IFEBS Journal Identification of mitogen-activated protein extracellular signal-responsive kinase kinase 2 as a novel partner of the scaffolding protein human homolog of disc-large Oumou Maiga1 Monique Philippe1 Larissa Kotelevets2 Eric Chastre2 Samira Benadda3 Dominique Pidard1 Roger Vranckx1 and Laurence Walch1 1 INSERM U698 Université Paris 7 France 2 INSERM U773 Centre de Recherche Biomedicale Bichat Beaujon Paris France 3 Plateau de Microscopie Confocale ICB-IFR 02 Paris France Keywords human disc-large homolog human vascular smooth muscle cells MAPK ERK kinase 2 scaffold protein synapse-associated protein 97 Correspondence L. Walch INSERM U698 Cardiovascular Haematology Bio-Engineering and Remodelling Bichat-Claude Bernard Hospital 46 rue Henri Huchard F-75877 Paris Cedex 18 France Fax 33 1 40 25 86 02 Tel 33 1 40 25 75 22 E-mail Received 11 January 2011 revised 29 April 2011 accepted 20 May 2011 doi Human disc-large homolog hDlg also known as synapse-associated protein 97 is a scaffold protein a member of the membrane-associated guanylate kinase family implicated in neuronal synapses and epithelial-epithelial cell junctions whose expression and function remains poorly characterized in most tissues particularly in the vasculature. In human vascular tissues hDlg is highly expressed in smooth muscle cells VSMCs . Using the yeast two-hybrid system to screen a human aorta cDNA library we identified mitogen-activated protein extracellular signal-responsive kinase ERK kinase MEK 2 a member of the ERK cascade as an hDlg binding partner. Site-directed mutagenesis showed a major involvement of the PSD-95 disc-large ZO-1 domain-2 of hDlg and the C-terminal sequence RTAV of MEK2 in this interaction. Coimmunoprecipitation assays in both human VSMCs and human embryonic kidney 293 cells demonstrated that endogenous hDlg physically interacts with MEK2 but not with MEK1. Confocal microscopy suggested a colocalization .