tailieunhanh - Báo cáo khoa học: Increased flexibility and liposome-binding capacity of CD1e at endosomal pH
The plasma membrane proteins CD1a, CD1b and CD1c are expressed by human dendritic cells, the professional antigen-presenting cells of the immune system, and present lipid antigens to T lymphocytes. CD1e belongs to the same family of molecules, but accumulates as a membrane-associated form in the Golgi compartments of immature dendritic cells and as a soluble cleaved form in the lysosomes of mature dendritic cells. | 1FEBS Journal Increased flexibility and liposome-binding capacity of CD1e at endosomal pH Natalia Bushmarina1 2 Sylvie Tourne1 2 Gaelle Giacometti1 2 Francois Signorino-Gelo1 2 Luis F. Garcia-Alles3 4 Jean-Pierre Cazenave2 5 Daniel Hanau1 2 and Henri de la Salle1 2 1 INSERM UMR-S725 INSERM-Universite de Strasbourg France 2 Etablissement Francais du Sang-Alsace Strasbourg France 3 CNRS IPBS Institut de Pharmacologie et de Biologie Structurale Toulouse France 4 Universite de Toulouse UPS IPBS France 5 INSERM UMR-S949 Etablissement Francais du Sang-Alsace Strasbourg France Keywords CD1e conformationalchanges lipid binding structure surface plasmon resonance Correspondence H. de la Salle or N. Bushmarina Etablissement Francais du Sang-Alsace 10 rue Spielmann 67065 Strasbourg France Fax 33 388 212 544 Tel 33 388 212 525 E-mail Received 25 January 2011 revised 30 March 2011 accepted 4 April 2011 doi The plasma membrane proteins CD1a CD1b and CD1c are expressed by human dendritic cells the professional antigen-presenting cells of the immune system and present lipid antigens to T lymphocytes. CD1e belongs to the same family of molecules but accumulates as a membrane-associated form in the Golgi compartments of immature dendritic cells and as a soluble cleaved form in the lysosomes of mature dendritic cells. In lysosomes the N-terminal propeptide of CD1e is also cleaved but the functional consequences of this step are unknown. Here we investigated how the pH changes encountered during transport to lysosomes affect the structure of CD1e and its ligand-binding properties. Circular dichroism studies demonstrated that the secondary and tertiary structures of recombinant CD1e were barely altered by pH changes. Nevertheless at acidic pH guanidium chloride-induced unfolding of CD1e molecules required lower concentrations of denaturing agent. The nonfunctional L194P allelic variant was found
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