ISSN:
1365-3083
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Human MHC class I proteins are expressed on almost all nucleated cells as a heavy chain (about 45 kDa) non-covalently associated with β-microglobulin (12 kDa), In this report we show that MHC class I (MHC-I) proteins can also be associated with a 90-kDa protein in the cell membrane.Surface-radiolabelled cells were treated with dithiobis succinimidyl propionate (DSP) in order to preserve multimer protein complexes during cell lysis. The lysates were immunoprecipitated and analysed by SDS-PAGE and autoradiography, Immunoprecipitation of human MH C- I proteins co-precipitated another protein of about 90 kDa in molecular weight p90. p90wasco-precipitaled from all the MIIC-I expressing cells tested: WIT. Raji. Molt-4 and IFN-γ treated K562, but not from untreated, MHC-I negative K562. A 90-kDa protein was also co-precipitated with MHC-I from fresh peripheral blood mononueiear cells(PBMC). Furthermore, p90 was co-precipitated by different MoAbs lo the MHC-1 heavy chain or β2-microglobulin. bul not by control antibodies. Two additional co-precipitaling proteins al 34 kDa and 28 kDa were seen in MHC-I precipitates from Raji cells.Our results suggest that MHC-1 proteins and the 90-kDa protein are associated in the cell membrane, probably by a close but weak, non-covalent interaction. Two additional cell surface proteins at 34 kDa and 28 kDa seem to be MHC-I associated on Raji Burkitt's lymphoma cells.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-3083.1991.tb01540.x
