Full-length HLA-G1 and truncated HLA-G3 differentially increase HLA-E surface localization

Hum Immunol. 2012 Sep;73(9):898-905. doi: 10.1016/j.humimm.2012.06.007. Epub 2012 Jun 22.

Abstract

Human leukocyte antigen (HLA)-E plays a role in immune tolerance induction and its transport to the cell surface is limited and dependent on the availability of HLA class I signal peptide. The role of HLA-G in regulating HLA-E surface localization remains controversial. The aim of our study was to clarify whether full-length and truncated HLA-G isoforms regulate HLA-E surface localization. Using a retroviral expression system and flow cytometric analysis, we found that surface HLA-E levels were significantly higher in HLA-G1 (34.1±4.4%, p<0.005) and -G3 (15.3±1.8%, p<0.04) versus empty vector (9.0±1.0%) transductants. Biotinylation and Western blot studies revealed HLA-E surface protein was increased by 4.5- and 1.3-fold in HLA-G1 and -G3 versus empty vector transductants. Although no significant differences in transcript and protein levels were detected between HLA-G1 and -G3 transductants, surface levels of HLA-G1 were 2.5-fold higher than HLA-G3 by flow cytometric analysis and Western blotting. Taken together, our data demonstrate that full-length HLA-G1 and truncated -G3 differentially increase HLA-E surface localization.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Membrane / metabolism*
  • Gene Expression Regulation
  • HLA-G Antigens / genetics*
  • HLA-G Antigens / metabolism*
  • Histocompatibility Antigens Class I / metabolism*
  • Humans
  • K562 Cells
  • Protein Transport

Substances

  • HLA-E antigen
  • HLA-G Antigens
  • Histocompatibility Antigens Class I