Naslov
Internalization and intracellular localization of HLA molecules

Autori
Blagojević, Gordana ; Mahmutefendić, Hana, Le Bouteiller, Philippe ; Kučić, Natalia ; Ilić Tomaš, Maja ; Lučin, Pero

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
American Journal of Reproductive Immunology / Kenneth Beaman ; Daniel Rukavina - Oxford : Blackwell Publishing, 2007, 433-434

Skup
X International Congress of Reproductive Immunology

Mjesto i datum
Opatija, Hrvatska, 10.06.2007. - 14.06.2007

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
MHC class I molecules

Sažetak
Problem. MHC class I molecules could be found inside the cell and at the cell surface in the form of fully conformed trimoleculear complexes (full molecules) and various conformers devoid of the antigenic peptides (empty molecules). In this study we compared endocytic trafficking and intracellular localization of fully conformed and non-conformed different HLA molecules (HLA-G1, HLA-E, HLA-B7 and HLA-Cw6). Method of study. In our experiments we used murine fibroblastic J-26 cell line transfected with distinct HLA molecules (HLA-G1, HLA-E, HLA-Cw6 and HLA-B7) and human epithelial carcinoma (HeLa) cell line. Constitutive (after cycloheximide treatment) and induced (after mAb binding) internalization was followed by flow cytometry. Conversion of conformation was achieved by short low-pH treatment (45 sec ; pH 2.0). Markers of intracellular compartments were used in order to distinguish intracellular localization of HLA-molecules by confocal microscopy. The kinetics of degradation was determined by cell surface biotynilation and immunoprecipitation. Results. We have found that all HLA molecules spontaneously internalized from the cell surface, and fastest kinetics was observed for HLA-Cw6 and HLA-E molecules. Typically, empty and misfolded conformations internalized faster then fully conformed HLA molecules. Triton-X-100 treatment removed all conformed HLA molecules from the cell surface indicating their localization in non-organized membrane domains, whereas non-conformed HLA molecules were resistant to this treatment, indicating their localization in lipid rafts. Inside the cell, conformed HLA molecules accumulated in the juxtanuclear region, whereas non-conformed molecules were retained in large multivesicular pre-late-endosomal structures All investigated HLA-I molecules partially colocalized with EEA-1, besides conformed HLA-G1. There was no colocalization with Rab 5A, Lamp-1, as well as with Rab 5B (with exception for HLA-Cw6 molecules). Non-conformed molecules have shown weaker colocalization with TfR than conformed. Conclusions. From ours results we can conclude that non-classical HLA molecules undergo to the slow process of spontaneous internalization and recycling, and a small part of them enter the degradation pathway during each cycle. Non-conformed molecules are internalized with faster kinetics and directed into the large acidic retention vesicles that are before late endosomes in the degradation route of the endocytic pathway. The experiments are partially financed by Croatian Ministry of Science Grant No. 0620238-0223 and EMBIC project, European FP6, NoE, No. 512040, LSHM-CT-2004-512040.

Izvorni jezik
Engleski

Znanstvena područja
Temeljne medicinske znanosti

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