Naslov
Comparison of spontaneous and induced endocytosis of MHC class I molecules on P815 cells and murine embrional fibroblasts

Autori
Mahmutefendić, Hana ; Kučić, Natalia ; Blagojević, Gordana ; Lučin, Pero

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

Izvornik
Abstract book, (P 16) / Hrvatsko imunološko društvo - Rijeka : Hrvatsko imunološko društvo, 2004

Skup
Annual meeting, Croatian Immunological Society

Mjesto i datum
Opatija, Hrvatska, 08.10.2004. - 10.10.2004

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
spontaneous endocytosis; induced endocytosis; MHC class I molecules

Sažetak
PROBLEM To characterize the endocytic pathway of MHC class I molecules, we have studied the expression of Ld molecules on nonpolarized murine P815 cells. These molecules reach the cell surface in two conformations: full, composed of properly folded heavy chain,  2 – microglobulin ( 2m) and peptide, and empty, which is represented either by non-conformed heavy chains or hetrodimer of weakly associated non-conformed heavy chain and  2m. METHODS OF STUDY In order to investigate this mechanism, a palette of inhibitors of endocytosis and vesicular transport was used. Cycloheximide, an inhibitor of protein synthesis, induced spontaneous endocytosis of Ld molecules and their disappearance from the cell surface or degradation was followed by flow cytometry and Western blott. RESULTS As inhibitors of clathrine endocytosis, chlorpromazine (CP) and peroxovanadat, did not influence the internalization of full and empty Ld molecules. Filipin and nystatin, inhibitors of caveolar endocytosis, prevented downregulation of empty, but not of full Ld molecules. NH4Cl, prevented the degradation of majority of empty Ld. As inhibitors of recycling, CP and bafilomycin A1 caused surface increase, but intracellular increase of full Ld. CONCLUSIONS From these results we can conclude that both full and empty Ld molecules are internalized by caveolar endocytosis. A majority of full Ld molecules are recycled back to the cell surface, and only small amount is degraded. In contrast, one part of the empty Ld is recycled directly to the cell surface, and probably, a major part is transformed in early endosomes into full Ld molecules and transported to the cell surface.

Izvorni jezik
Engleski

Znanstvena područja
Temeljne medicinske znanosti

POVEZANOST RADA