tailieunhanh - Báo cáo khoa học: Membrane protein integration into the endoplasmic reticulum

Most integral membrane proteins are targeted, inserted and assembled in the endoplasmic reticulum membrane. The sequential and potentially over-lapping events necessary for membrane protein integration take place at sites termed translocons, which comprise a specific set of membrane pro-teins acting in concert with ribosomes and, probably, molecular chaperones to ensure the success of the whole process. | IFEBS Journal REVIEW ARTICLE Membrane protein integration into the endoplasmic reticulum Luis Martinez-Gil1 2 Ana Sauri3 Marc A. Marti-Renom4 and Ismael Mingarro1 1 Departament de Bioquimica i Biologia Molecular Universitat de Valencia Burjassot Spain 2 Department of Microbiology Mount Sinai Schoolof Medicine New York NY USA 3 Department of Molecular Microbiology Institute of Molecular CellBiology VU University Amsterdam The Netherlands 4 StructuralGenomics Laboratory Centro de Investigacion Príncipe Felipe Valencia Spain Keywords biogenesis insertion membrane protein translocon transmembrane segment Correspondence I. Mingarro Departament de Bioquimica i Biologia Molecular Universitat de Valencia E46100 Burjassot Spain Fax 34 963544635 Tel 34 963543796 E-mail These authors contributed equally to this work Received 6 April 2011 revised 13 May 2011 accepted 17 May 2011 doi Most integral membrane proteins are targeted inserted and assembled in the endoplasmic reticulum membrane. The sequential and potentially overlapping events necessary for membrane protein integration take place at sites termed translocons which comprise a specific set of membrane proteins acting in concert with ribosomes and probably molecular chaperones to ensure the success of the whole process. In this minireview we summarize our current understanding of helical membrane protein integration at the endoplasmic reticulum and highlight specific characteristics that affect the biogenesis of multispanning membrane proteins. Introduction Helical integral membrane proteins have essential roles in the cell and account for almost one-fourth of all proteins in most organisms 1 . However our understanding of their biosynthesis and folding lags far behind our understanding of water-soluble proteins. The targeting and insertion of most integral membrane proteins in eukaryotic cells occur cotranslationally whereby protein synthesis and integration into .