Tissue plasminogen activator has an O-linked fucose attached to threonine-61 in the epidermal growth factor domain

Abstract

An unusual type of glycosylation has been observed for tissue plasminogen activator (t-PA). The monosaccharide fucose is glycosidically linked to threonine-61 in the epidermal growth factor region of t-PA. The presence of O-linked fucose was demonstrated by carbohydrate analysis and mass spectrometry of tryptic and chymotryptic peptides that contain this site. The susceptibility of the fucose residue to alpha-fucosidase indicated that it was in the alpha-anomeric configuration. Fucosylation of threonine-61 was observed in t-PA isolated from the Bowes melanoma cell line and from recombinant expression systems using Chinese hamster ovary or human embryonic kidney cells. Fucosylation of the homologous residue in prourokinase has also been reported recently. Our results indicate that this novel type of glycosylation may be common to the epidermal growth factor domains found in coagulation and fibrinolytic proteins and, therefore, suggest that the modification may have functional significance.

Amino Acid Sequences of Metalloendopeptidases Specific for Acyl-Lysine Bonds from Grifola frondosa and Pleurotus ostreatus Fruiting Bodies

“…Attachment of a single sugar residue to the hydroxyl group of Ser or Thr residue has received particular attention, because O-GlcNAc bound to the hydroxyl amino acid residues has been extensively investigated with respect to the functions of the proteins (24). Recently, an L-fucosyl residue bound to Thr O-glycosidically has been characterized in several proteins (25)(26)(27)(28). However, to our best knowledge, identification of ␣-mannosylated GFMEP is the first report that presented unambiguous evidence for the O-glycosidic linkage of a D-mannose residue to the hydroxyl group of a Thr residue in protein.…”

Differential Terminal Fucosylation of N-Linked Glycans Versus Protein O-Fucosylation in Leukocyte Adhesion Deficiency Type II (CDG IIc)

“…O-fucose modifications have been reported to occur in two distinct sequence contexts: epidermal growth factor-like (EGF) 1 repeats (8) and thrombospondin type 1 repeats (TSR) (10). Serum proteins, involved in blood clotting or clot dissolution, such as human factor VII, factor XII, uPA (urokinase-type plasminogen activator) and tPA (tissue type plasminogen activator), are modified by O-fucose as a simple monosaccharide at a specific consensus sequence within their EGF repeats (11)(12)(13)(14)(15)(16). Elongation of the O-fucose monosaccharide on EGF repeats to a tetrasaccharide can occur in a proteinspecific manner (e.g.…”

Serine-proteases as plasminogen activators in terms of fibrinolysis

“…Alteplase (rt-PA) Human [2], [29][30][31][32][33][34][35][36][37][38][39][40], [42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59] Gly-Pro-Arg (GPR) at the a-chain and Gly-His-Arg (GHR) at the b-chain. They are positively charged and are called 'knobs' , leading to polymerization by non-covalent interaction with negatively charged 'holes' in the carboxy-terminal region of the g-chain (a-g) or b-chain (b-b) of other fibrin monomers.…”