Some years ago, a lectin designated CBP70 that recognized glucose (Glc
) but had a stronger affinity for N-acetylglucosamine (GlcNAc), was fi
rst isolated from HL60 cell nuclei. Recently, a cytoplasmic form of th
is lectin was described, and one 82 kDa nuclear ligand was characteriz
ed for the nuclear CBP70. In the present study, the use of Pronase dig
estion and the trifluoromethanesulphonic acid (TFMS) procedure strongl
y suggest that the nuclear and the cytoplasmic CBP70 have a same 23 kD
a polypeptide backbone and, consequently, could be the same protein. I
n order to know the protein better and to obtain the best recombinant
possible in the future, the post-translational modification of the nuc
lear and cytoplasmic CBP70 was analyzed in terms of glycosylation; Sev
erals lines of evidence indicate that both forms of CBP70 are N- and O
-glycosylated. Surprisingly, this glycosylation pattern differs betwee
n the two forms, as revealed by beta-elimination, hydrazinolysis, pept
ide-N-glycosydase F (PNGase F), and TFMS reactions. The two preparatio
ns were analyzed by affinity chromatography on immobilized lectins [Ri
cinus communis-l agglutinin (RCA-I), Arachis hypogaea agglutinin (PNA)
, Galanthus nivalis agglutinin (GNA), and wheat germ agglutinin (WGA)]
and by lectin-blotting analysis [Sambucus nigra agglutinin (SNA), Maa
ckia amurensis agglutinin (MAA), Lotus tetragonolobus (Lotus), succiny
lated-WGA, and Psathyrella velutina agglutinin (PVA)]. Both forms of C
BP70 have the following sugar moities: terminal beta Gal residues, Gal
beta 1-3 GalNAc, Man alpha 1-3 Man, sialic acid alpha 2-6 linked to G
al or GalNAc; and sialic acid alpha 2-3 linked to Gal. However, only n
uclear CBP70 have terminal GlcNAc and alpha-L-fucose residues. All the
se data are consistent with the fact that different glycosylation patt
ern found for each form of CBP70 might act as a complementary signal f
or cellular targeting. (C) 1997 Wiley-Liss, Inc.