FULL CHARACTERIZATION OF NATURAL KILLER CELL MEMBRANE MICRODOMAINS

P. Man^1,2, P. Novák^1,2, P. Pompach^1,2, D. Ulbrichová^1,2, V. Havlíček¹, K. Bezouška^1,2

¹Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, CZ

²Department of Biochemistry, Faculty of Science, Charles University, Prague, CZ

Natural killer (NK) cells are cytotoxic effector lymphocytes, which do not express antigen-specific cell surface receptors. NK receptors that mediate signals leading to the initiation or supression of natural cytotoxicity processes are poorly characterized. Moreover, these receptors may associate with other co-stimulating molecules and adaptor proteins, which transduce the signal from the receptor to the cell. Such complexes may be observed as biochemically distinct parts of plasmatic membranes and are commonly referred to micro domains or glycosphingolipid enriched microdomains (GEMs). They are enriched in GPI-anchored and acetylated proteins and in cholesterol and glycosphingolipids. It is believed that they may aid in signal transduction as well as in trafficking through the secretory and endocytic pathways and in cell to cell interaction.

In this study we focused on membrane microdomains from rat NK leukaemia cell line (RNK-16). For detailed characterization we used a shotgun strategy based on microcapillary HPLC – tandem mass spectrometry. Aditionally, we applied techniques of native electrophoresis for detailed mapping of protein complexes present in the GEMs. We have identified a large number of proteins (e.g. gp-42, CD2, LAT, CD161, CD44 or g-proteins in GEM and tubuline in non-GEM fractions).

Financial support: MSM 113100001, AV0Z5020903.