Nucleophosmin is a component of the fructoselysine-specific receptor in cell membranes of Mono Mac 6 and U937 monocyte-like cells

Abstract

The monocyte-like cell lines Mono Mac 6 (MM6) and U937 bind Amadori-modified proteins via fructoselysine (FL)-specific sites with molar masses of 110, 150 and 200 kDa, which can specifically be isolated by an affinity method with magnetobeads coated with glycated polylysine. Using Western blots developed with different anti-nucleophosmin antisera, MS-analysis and immunohistochemistry, we show that the nucleolar protein nucleophosmin is also localized in the cell membrane and is part of the 150- and 200-kDa membrane protein fractions of FL-specific binding membrane proteins. This is the first evidence that nucleophosmin is not only existing in the nucleolus and cytoplasm, but also, like nucleolin, is in the cell membrane.