Characterization of membrane-bound collagen galactosyltransferase of human blood platelets

Barber, A.J.; Jamieson, G.A.

doi:10.1016/0304-4165(71)90157-7

Cited by 51 publications

(15 citation statements)

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“…The platelet receptor in this case may be the glycosyl transferases (16)(17)(18)(19)(20). The affinity between this site and the collagen carbohydrate is much less than that of the other site and the collagen protein.…”

Section: Collagen-platelet Interactions 2497mentioning

confidence: 99%

“…It was initially shown by Butler and Cunningham (13,14) that soluble collagen contains only galactose and galactosyl-glucose units O-glycosidically linked to the hydroxyl group of hydroxylysine. The insoluble collagen fraction was later shown by Cunningham and Ford (15) (16)(17)(18) has led to the proposal (18)(19)(20) that the collagen carbohydrate sidechain represents the "recognition site" and that the binding involves an enzyme-substrate (or inhibitor) type interaction, e.g., platelet-glucosyltransferase complexed with collagen-gal. This hypothesis is a specific example of Roseman's (21) generalized theory regarding intercellular interactions and Cunningham's (22) suggestions pertinent to the role of glycoproteins in cellular recognition.…”

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confidence: 99%

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Collagen-Mediated Platelet Aggregation EFFECTS OF COLLAGEN MODIFICATION INVOLVING THE PROTEIN AND CARBOHYDRATE MOIETIES

Puett¹,

Wasserman²,

Ford³

et al. 1973

J. Clin. Invest.

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A B ST R A CT In an effort to elucidate the nature of the collagen-platelet interaction, the effects of collagen modification on platelet aggregation have been studied. We have shown that purified rat skin (salt) soluble collagen is effective at about 20 nM in mediating platelet aggregation in human platelet-rich plasma. This conce-ntration is somewhat greater than that required of several skin insoluble collagens (ca. 10 nM). Both the al(I) and a2 chains from rat skin soluble collagen produced platelet aggregation, but only at concentrations of about 13 AM and 55 AM, respectively. In contrast, heat-denatured collagen and chains (e.g., 65 AM al(I) and 160 AM a2) failed to induce platelet aggregation and to inhibit platelet aggregation by native collagen.Glycopeptides were prepared from human skin insoluble collagen by extended digestion with bacterial collagenase and trypsin, and were purified by gel filtration into two classes. One class of higher molecular weight contained sialic acid, glucosamine, galactosamine, fucose, mannose, galactose, and glucose, and the other of lower molecular weight consisted primarily of a mixture of galactose and galactosyl-glucose units O-glycosidically linked to hydroxylysine-containing peptides. We found that, after the residual tryptic activity contaminating the higher molecular weight fraction was inhibited, neither of the glycopeptide classes produced nor inhibited native human skin insoluble collagen-mediated platelet aggregation at the highest concentration examined (ca. 1-2 mg glycopeptide per ml of platelet-rich plasma glucose (Hyl-Gal and Hyl-Gal-Glc, respectively), were prepared from human urine and labeled at galactose using galactose oxidase followed by reduction with tritiated borohydride. Binding studies with platelet-rich plasnma showed that, at concentrations greater than 50 nM, Hyl-Gal gives apparent binding to platelets, but there was no evidence of Hyl-Gal-Glc binding to platelets at concentrations up to 250 nM. At concentrations several hundredfold higher than the equivalents present in the minimum concentration of rat skin soluble collagen required for platelet aggregation, neither Hyl-Gal (at 29 iM) nor Hyl-Gal-Glc (at 18 AM) caused platelet aggregation or inhibited platelet aggregation by native collagen. Also, at a concentration of 85 ,M (which represents a concentration about two thousandfold higher than the equivalents in the minimum concentration of soluble collagen required for platelet aggregation) the Gal-Glccontaining 36 residue rat skin soluble collagen al(I)-cyanogen bromide #5 peptide had no platelet aggregating or inhibiting activity.Modification of at least 90% of the rat skin soluble collagen carbohydrate by mild periodate oxidation had no effect on the platelet aggregating activity. Human skin insoluble collagen was reacted with periodate under the same conditions, and this had no demonstrable effect on its ability to induce platelet aggregation. This indicates that the normal carbohydrate side chains of these collagens are not required for t...

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Section: Collagen-platelet Interactions 2497mentioning

confidence: 99%

mentioning

confidence: 99%

Collagen-Mediated Platelet Aggregation EFFECTS OF COLLAGEN MODIFICATION INVOLVING THE PROTEIN AND CARBOHYDRATE MOIETIES

Puett¹,

Wasserman²,

Ford³

et al. 1973

J. Clin. Invest.

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“…12 Glycosyltransferase activities in platelets were described 30 years ago and are proposed to mediate different aspects of platelet functions. 7,6,13,14 These findings were surprising because platelets lack an organized glycosylation apparatus, and conclusive information is sparse regarding the biologic function of glycosyltransferases in platelets. We provided evidence previously that platelets have a surface-associated ␤4-galactosyltransferase 1 (␤4Gal-T1) that couples galactose in a ␤1,4 linkage to N-acetylglucosaminyl (GlcNAc) bearing glycans on the GPIb␣ subunit of the VWF receptor, a process that improves the circulation of refrigerated platelets.…”

mentioning

confidence: 92%

“…5 One notable exception concerns reports of glycosyltransferase activities associated with blood platelets. [6][7][8][9][10][11] Platelets are anucleated megakaryocyte subfragments that participate in hemostatic, inflammatory, and host defense reactions. 12 Moreover, platelets deliver pro-and antiangiogenic factors throughout the vascular system.…”

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confidence: 99%

The origin and function of platelet glycosyltransferases

Wandall

Rumjantseva

Sørensen

et al. 2012

Blood

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Platelets are megakaryocyte subfragments that participate in hemostatic and host defense reactions and deliver proand antiangiogenic factors throughout the vascular system. Although they are anucleated cells that lack a complex secretory apparatus with distinct Golgi/ endoplasmic reticulum compartments, past studies have shown that platelets have glycosyltransferase activities. In the present study, we show that members of 3 distinct glycosyltransferase families are found within and on the surface of platelets. Immunocytology and flow cytometry results indicated that megakaryocytes package these Golgi-derived glycosyltransferases into vesicles that are sent via proplatelets to nascent platelets, where they accumulate. These glycosyltransferases are active, and intact platelets glycosylate large exogenous substrates. Furthermore, we show that activation of platelets results in the release of soluble glycosyltransferase activities and that platelets contain sufficient levels of sugar nucleotides for detection of glycosylation of exogenously added substrates. Therefore, the results of the present study show that blood platelets are a rich source of both glycosyltransferases and donor sugar substrates that can be released to function in the extracellular space. This plateletglycosylation machinery offers a pathway to a simple glycoengineering strategy improving storage of platelets and may serve hitherto unknown biologic functions. (Blood. 2012;120(3):626-635) IntroductionGlycosylation of proteins and lipids has a wide range of biologic functions. 1 The glycosylation apparatus of nucleated cells is primarily located in the secretory pathway throughout the endoplasmic reticulum-Golgi stacks and consists of more than 200 glycosyltransferases, most of which are type II transmembrane-anchored proteins with distinct localization. Their topology within these compartments is directed by signal motifs contained in their stem, transmembrane, and cytoplasmic domains. 2,3 Golgi-located membrane-bound glycosyltransferases are believed to be retained in the appropriate compartments by coat protein I-mediated retrograde transport 3 and to be released and secreted only after proteolytic cleavage in their stalk regions to yield soluble, catalytically active truncated enzymes lacking their N-terminal transmembrane segment. 4 Several previous studies have described unusual subcellular localization of glycosyltransferases outside of their normal confinement to the endoplasmic reticulum-Golgi (referred to herein as ectopic localization). Methodologic ambiguities, however, have cast doubt on these findings. 5 One notable exception concerns reports of glycosyltransferase activities associated with blood platelets. [6][7][8][9][10][11] Platelets are anucleated megakaryocyte subfragments that participate in hemostatic, inflammatory, and host defense reactions. 12 Moreover, platelets deliver pro-and antiangiogenic factors throughout the vascular system. 12 Glycosyltransferase activities in platelets were described 30 years ago and are propo...

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“…Because the collagen-platelet interaction is an important event in hemostasis, a great deal of interest has centered on the determination of the mechanism of the interaction. A major stimulus to interest in the collagen-platelet interaction came as a result of the investigations of Barber and Jamieson (4,5). They presented evidence that membrane-bound glucosyl transferases on the surface of platelets bind to the galactose and glucose residues of collagen in an enzyme-substrate and enzyme-product complex, respectively.…”

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confidence: 99%

Evidence that fibronectin is the collagen receptor on platelet membranes.

Bensusan¹,

Koh²,

Henry³

et al. 1978

Proc. Natl. Acad. Sci. U.S.A.

113

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Evidence is presented that fibronectin is present on the platelet cell membrane and that it is a receptor for collagen in the platelet-collagen interaction. First, sodium dodecyl sulfate/acrylamide gel electrophoresis was performed on the proteins remaining attached to the surface of collagen after the removal of the remainder of the platelet by sonication. The material was relatively enriched in a glycoprotein that comigrated with cold-insoluble globulin (CIG), a form of fibronectin, and in other proteins which comigrated with myosin, actin, and tropomyosin. The presumptive presence of contractile proteins is consistent with the presence of microfibrillar proteins. Second, the collagen-attached material was shown to contain a protein that reacted'with anti-GIG serum by immunoelectrophoresis. Third, when CIG was preincubated with fibrous collagen, the platelet-collagen interaction was inhibited. Fourth, rabbit anti-human CIG stimulated human platelets to secrete the contents of their dense granules. The stimulation was not due to antibody complexes present in the solution. Fifth, a protein was extracted from wel -washed platelets and purified on affinity columns of anti-GIG antibodies. The isolated protein was found to bind to fibrous collagen. When the endothelial lining of blood vessels is breached, blood platelets come in contact with the components of connective tissue. The platelets adhere to the collagen in the connective tissue and are stimulated to release the contents of their dense granules, including ADP, Ca2+, and serotonin (1, 2). The Ca2+ and ADP are required for the subsequent platelet-platelet interactions, which lead to the formation of aggregates on a nucleus of the platelets bound to collagen (3). The aggregates form a platelet plug as an initial step in hemostasis. Because the collagen-platelet interaction is an important event in hemostasis, a great deal of interest has centered on the determination of the mechanism of the interaction. A major stimulus to interest in the collagen-platelet interaction came as a result of the investigations of Barber and Jamieson (4, 5). They presented evidence that membrane-bound glucosyl transferases on the surface of platelets bind to the galactose and glucose residues of collagen in an enzyme-substrate and enzyme-product complex, respectively. Further investigations by others tended to support this hypothesis (6, 7). However, evidence to the contrary has been presented. Menashi et al. (8) have shown that only denatured collagen can act as a substrate for the platelet glucosyl transferase, whereas only native, fibrous collagen serves as a platelet substrate in the collagen-platelet interaction (9, 10). In addition, others have shown that the carbohydrate residues of collagen can be completely destroyed by periodate oxidation without affecting the ability of the fibrous form of the oxidized collagen to interact normally with platelets (10, 11).Because the only current hypothesis as to the nature of the collagen receptor of platelets has been severe...

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Characterization of membrane-bound collagen galactosyltransferase of human blood platelets

Cited by 51 publications

References 6 publications

Collagen-Mediated Platelet Aggregation EFFECTS OF COLLAGEN MODIFICATION INVOLVING THE PROTEIN AND CARBOHYDRATE MOIETIES

Collagen-Mediated Platelet Aggregation EFFECTS OF COLLAGEN MODIFICATION INVOLVING THE PROTEIN AND CARBOHYDRATE MOIETIES

The origin and function of platelet glycosyltransferases

Evidence that fibronectin is the collagen receptor on platelet membranes.

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