Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: The E5 protein of the human papillomavirus type 16 down-regulates HLA-I surface expression in calnexin-expressing but not in calnexin-deficient c | Virology Journal BioMed Central Research Open Access The E5 protein of the human papillomavirus type 16 down-regulates HLA-I surface expression in calnexin-expressing but not in calnexin-deficient cells Myriam Gruener1 Ignacio G Bravo 2 5 Frank Momburg3 Angel Alonso1 and Pascal Tomakidi4 Address 1Division of Cell Differentiation German Cancer Research Center Heidelberg Germany 2Division of Genome Modifications and Carcinogenesis German Cancer Research Center Heidelberg Germany 3Division of Molecular Immunology German Cancer Research Center Heidelberg Germany 4Department of Dental Medicine University of Heidelberg Heidelberg Germany Germany and 5Experimental Molecular Evolution. Institute for Evolution and Biodiversity University of Muenster Muenster Germany Email Myriam Gruener - Ignacio G Bravo - igbravo@ Frank Momburg - Angel Alonso - Pascal Tomakidi - pascal_tomakid@ Corresponding author Published 30 October 2007 Received 7 September 2007 Accepted 30 October 2007 Virology Journal 2007 4 116 doi 1743-422X-4-116 This article is available from http content 4 1 1 16 2007 Gruener et al licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License http licenses by which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. Abstract The human papillomavirus type 16 E5 protein HPV16 E5 down-regulates surface expression of HLA-I molecules. The molecular mechanisms underlying this effect are so far unknown. Here we show that HPV16 E5 down-regulates HLA-I surface expression in calnexin-containing but not in calnexin-deficient cells. Immunoprecipitation experiments reveal that calnexin and HPV16E5 can be co-precipitated and that this association depends on the presence of a wild-type first hydrophobic region