Naslov
Endocytosis of full and empty Ld molecules on nonpolarized cells

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

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

Izvornik
1. kongres Hrvatskog društva fiziologa, Osijek, 14.-16. rujna 2000. = 1st Congress of the Croatian Physiological Society, Osijek, 14th-16th September 2000 : [knjiga sažetaka] / Vitale, Branko - Osijek : Hrvatsko društvo fiziologa, 2000, 19-19

Skup
1. kongres Hrvatskog društva fiziologa = 1st Congress of the Croatian Physiological Society

Mjesto i datum
Osijek, Hrvatska, 14.09.2000. - 16.09.2000

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
endocytosis; full and empty Ld molecules; inhibitors of endocytosis

Sažetak
To characterize endocytic pathway of MHC class I molecules, we have studied cell surface 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, ƒŇ2-microglobulin (ƒŇ2-m) and peptide, and empty, which is represented either by non-conformed heavy hain and ƒŇ2-m. These two conformations are distinguished by conformation-specific monoclonal antibodies. In order to investigate the mechanism of Ld molecule backsorting from the cell surface, a palette of inhibitors of endocytosis and vesicular transport was used. Cycloheximide, an inhibitor of protein synthesis, included spontaneous endocytosis of Ld molecules and their disappearance from the cell surface was followed by flow cytometry. Inhibitors clathrine nedocytosis, chlorpromazine and peroxovanadat, did not influence the internalization of full and empty Ld molecules. Filipin and nystatin, inhibitors of caveolar endicytosis, prevented downregulation of empty, but not of full Ld molecules. The inhibitors of lysosomal degradation, nocodazole and leupeptin, caused upregulation of full, but empty Ld molecules. The situation was reversed with NH4Cl. As an inhibitor of recycling pathway, chlorpromazine downregulated both full and empty Ld molecules. From these results we can conclude that both fll and empty Ld molecules are internalized by caveolar endocytosis, but empty with much faster kinetic (80% after 24hrs). A majority of full Ld molecules are recycled back to the cell surface, and only small amount is degraded. In contrast, one part of 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

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