Expression of heparan sulphate L-iduronyl 2-O-sulphotransferase in human kidney 293 cells results in increased D-glucuronyl 2-O-sulphation.
Functionally important interactions between heparan sulphate and a variety of proteins depend on the precise location of O-sulphate groups. Such residues occur at C-2 of L-iduronic (IdoA) and D-glucuronic acid (GlcA) units, and at C-3 and C-6 of D-glucosamine (GlcN) units. Stable transfection of human embryonic kidney 293 cells with a cDNA encoding mouse mastocytoma IdoA 2-O-sulphotransferase resulted in an approx. 6-fold increase in O-sulphotransferase activity, compared with control cells, as determined using O-desulphated heparin as an acceptor. Structural analysis of endogenous heparan sulphate in the transfected cells, following metabolic labelling with either [(3)H]GlcN or [(35)S]sulphate, showed appreciable formation of -GlcA(2-OSO(3))-GlcNSO(3)- disaccharide units (6% of total disaccharide units; 17% of total O-sulphated disaccharide units) that were essentially absent from heparan sulphate from control cells. The increase in GlcA 2-O-sulphation was accompanied by a decrease in the amount of IdoA formed, whereas overall 2-O-sulphation or 6-O-sulphation remained largely unaffected. These findings indicate that 2-O-sulphation of IdoA and GlcA residues is catalysed by the same enzyme in heparan sulphate biosynthesis.
Rong
J
J
Department of Medical Biochemistry and Microbiology, University of Uppsala, The Biomedical Center, Box 582, S-751 23 Uppsala, Sweden.
Habuchi
H
H
Kimata
K
K
Lindahl
U
U
Kusche-Gullberg
M
M
D000818:Animals; D002238:Carbohydrate Epimerases / Q000378:metabolism*; D002460:Cell Line; D005965:Glucuronates / Q000378:metabolism; D019812:Heparan Sulfate Proteoglycans / Q000378:metabolism*; D006801:Humans; D007668:Kidney / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D015238:Sulfotransferases / Q000378:metabolism*
D005965:Glucuronates; D019812:Heparan Sulfate Proteoglycans; D015238:Sulfotransferases; C406782:heparan sulfate L-iduronyl 2-O-sulfotransferase; D002238:Carbohydrate Epimerases