scholarly journals Platelet protein organization: analysis by treatment with membrane- permeable cross-linking reagents

Blood ◽  
1982 ◽  
Vol 59 (3) ◽  
pp. 502-513 ◽  
Author(s):  
GE Davies ◽  
J Palek

Abstract We have examined platelet protein organization by treatment of intact resting or thrombin-activated platelets with two cross-linking reagents, diamide or dithiobis(succinimidyl propionate) (DTSP). Cross- linked complexes were separated by polyacrylamide gel electrophoresis in the absence of reducing agent and their composition determined after reductive cleavage and analysis in a second-dimensional gel. The most prominent cross-linked species produced by diamide treatment of of resting platelets are (A) cytoskeletal protein homopolymers, such as myosin heavy chain dimer and actin oligomers, and (B) high molecular weight material consisting of homo- or heteropolymers of cytoskeletal proteins and 230,000, 170,000, 100,000, 55,000, and 52,000 dalton proteins. DTSP treatment forms similar complexes and also cross-links membrane glycoproteins IIb and III into high molecular weight material. Thrombin activation of platelets before treatment with diamide or DTSP results in increased cross-linking of myosin and increased incorporation of several proteins, particularly myosin and glycoproteins IIb and III, into high molecular weight material. The results provide evidence for reorganization of cytoskeletal and membrane proteins during platelet function.

Blood ◽  
1982 ◽  
Vol 59 (3) ◽  
pp. 502-513
Author(s):  
GE Davies ◽  
J Palek

We have examined platelet protein organization by treatment of intact resting or thrombin-activated platelets with two cross-linking reagents, diamide or dithiobis(succinimidyl propionate) (DTSP). Cross- linked complexes were separated by polyacrylamide gel electrophoresis in the absence of reducing agent and their composition determined after reductive cleavage and analysis in a second-dimensional gel. The most prominent cross-linked species produced by diamide treatment of of resting platelets are (A) cytoskeletal protein homopolymers, such as myosin heavy chain dimer and actin oligomers, and (B) high molecular weight material consisting of homo- or heteropolymers of cytoskeletal proteins and 230,000, 170,000, 100,000, 55,000, and 52,000 dalton proteins. DTSP treatment forms similar complexes and also cross-links membrane glycoproteins IIb and III into high molecular weight material. Thrombin activation of platelets before treatment with diamide or DTSP results in increased cross-linking of myosin and increased incorporation of several proteins, particularly myosin and glycoproteins IIb and III, into high molecular weight material. The results provide evidence for reorganization of cytoskeletal and membrane proteins during platelet function.


Blood ◽  
1983 ◽  
Vol 62 (4) ◽  
pp. 800-807 ◽  
Author(s):  
MC Berndt ◽  
C Gregory ◽  
BH Chong ◽  
H Zola ◽  
PA Castaldi

Abstract The glycoprotein profile of Bernard-Soulier platelets was examined by labeling washed platelets with periodate 3H-sodium borohydride, a procedure that labels greater than 30 glycoproteins on the membrane surface of normal platelets. Three Bernard-Soulier patients were studied; two were siblings and the third was unrelated. The platelet protein and glycoprotein profiles were evaluated under nonreduced and reduced conditions using 5%-15% exponential SDS-polyacrylamide gel electrophoresis. The two siblings completely lacked glycoprotein Ib (GPIb). The unrelated patient had congruent to 7% of the normal level. This was confirmed by two-dimensional nonreduced-reduced SDS- polyacrylamide gel electrophoresis, a procedure that allows clear separation of the disulfide-linked subunits of GPIb, GPIb alpha (mol wt 145,000), and GPIb beta (mol wt 25,000) from other membrane glycoproteins. On one-dimensional analysis, Bernard-Soulier's syndrome (BSS) platelets also lacked the peripheral membrane glycoprotein, GPV (mol wt 82,000) and a low molecular weight glycoprotein, GPIX, (nonreduced or reduced, mol wt congruent to 22,000). The two- dimensional gel system also revealed the absence of a minor glycoprotein with a molecular weight of congruent to 100,000 (GP 100). Quantitation of these proteins solubilized from electrophoretograms showed that the siblings' parents had congruent to 50% levels of GPIb, GPIX, and GP 100. A monoclonal antibody against glycoprotein Ib, FMC 25, was negative by immunofluorescence against Bernard-Soulier platelets and immuneprecipitated both GP Ib and GPIX from Triton X100 solubilized, labeled platelets. The combined results suggest that the apparent genetic absence of multiple proteins in Bernard-Soulier platelets is due, in part, to the presence in normal platelets of a tight membrane complex between glycoprotein Ib and at least one of the other absent glycoproteins.


1975 ◽  
Vol 49 (2) ◽  
pp. 149-156 ◽  
Author(s):  
P. J. Gaffney ◽  
D. A. Lane ◽  
M. Brasher

1. The factor XIII-mediated cross-linked α chains in fibrin have no effect on the nature of the fragments released during the solubilization of fibrin by plasmin. 2. Besides the known D dimer and E fragments solubilized during the lysis of cross-linked fibrin, other fragments have been observed on sodium dodecyl sulphate-polyacrylamide gel electrophoresis which have a molecular weight of about 135 000. After prolonged plasmin digestion, these fragments (U fragments) were no longer evident on the gels and the high-molecular-weight E antigen was absent. It is assumed that the E antigen was associated with the U fragments. These fragments also cross-reacted with an anti-D serum. 3. The U fragments have been tentatively presumed to be a factor XIII-mediated cross-linked D–E complex since they degrade only after prolonged degradation with plasmin. Whereas it is known that the fibrin D dimer fragment contains the cross-linked γ chain residues of the originating fibrin, the presumed covalent cross-linking of the D–E fragments has not been proved. 4. The presence of these high-molecular-weight fragments, containing the E antigen, in cross-linked human fibrin digests should be taken into account in the development of D dimer assays to monitor fibrin lysis in vivo.


Blood ◽  
1983 ◽  
Vol 62 (4) ◽  
pp. 800-807 ◽  
Author(s):  
MC Berndt ◽  
C Gregory ◽  
BH Chong ◽  
H Zola ◽  
PA Castaldi

The glycoprotein profile of Bernard-Soulier platelets was examined by labeling washed platelets with periodate 3H-sodium borohydride, a procedure that labels greater than 30 glycoproteins on the membrane surface of normal platelets. Three Bernard-Soulier patients were studied; two were siblings and the third was unrelated. The platelet protein and glycoprotein profiles were evaluated under nonreduced and reduced conditions using 5%-15% exponential SDS-polyacrylamide gel electrophoresis. The two siblings completely lacked glycoprotein Ib (GPIb). The unrelated patient had congruent to 7% of the normal level. This was confirmed by two-dimensional nonreduced-reduced SDS- polyacrylamide gel electrophoresis, a procedure that allows clear separation of the disulfide-linked subunits of GPIb, GPIb alpha (mol wt 145,000), and GPIb beta (mol wt 25,000) from other membrane glycoproteins. On one-dimensional analysis, Bernard-Soulier's syndrome (BSS) platelets also lacked the peripheral membrane glycoprotein, GPV (mol wt 82,000) and a low molecular weight glycoprotein, GPIX, (nonreduced or reduced, mol wt congruent to 22,000). The two- dimensional gel system also revealed the absence of a minor glycoprotein with a molecular weight of congruent to 100,000 (GP 100). Quantitation of these proteins solubilized from electrophoretograms showed that the siblings' parents had congruent to 50% levels of GPIb, GPIX, and GP 100. A monoclonal antibody against glycoprotein Ib, FMC 25, was negative by immunofluorescence against Bernard-Soulier platelets and immuneprecipitated both GP Ib and GPIX from Triton X100 solubilized, labeled platelets. The combined results suggest that the apparent genetic absence of multiple proteins in Bernard-Soulier platelets is due, in part, to the presence in normal platelets of a tight membrane complex between glycoprotein Ib and at least one of the other absent glycoproteins.


1977 ◽  
Vol 163 (3) ◽  
pp. 449-453 ◽  
Author(s):  
M B Baird ◽  
H R Massie ◽  
L S Birnbaum

Ultracentrifugation studies of purified mouse hepatic catalase revealed that 5-7% of the total material consists of a form with a higher molecular weight than the bulk of the catalase. The two components were separated by sucrose-gradient centrifugation. Polyacrylamide-gel electrophoresis (in borate buffer) demonstrated that high-molecular-weight catalase is enriched in a more slowly migrating component, and sodium dodecyl sulphate/polyacrylamide gel-electrophoresis demonstrated that the molecular weight of the subunits of the high-molecular-weight material is identical with that of the subunits of the major form. These results suggest that high-molecular-weight catalase consists of subunits that are not markedly distinct from those present in the normal catalase tetramer.


1980 ◽  
Vol 189 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Yoav Ben-Yoseph ◽  
Melinda Hungerford ◽  
Henry L. Nadler

Galactocerebrosidase (β-d-galactosyl-N-acylsphingosine galactohydrolase; EC 3.2.1.46) activity of brain and liver preparations from normal individuals and patients with Krabbe disease (globoid-cell leukodystrophy) have been separated by gel filtration into four different molecular-weight forms. The apparent mol.wts. were 760000±34000 and 121000±10000 for the high- and low-molecular-weight forms (peaks I and IV respectively) and 499000±22000 (mean±s.d.) and 256000±12000 for the intermediate forms (peaks II and III respectively). On examination by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, the high- and low-molecular-weight forms revealed a single protein band with a similar mobility corresponding to a mol.wt. of about 125000. Antigenic identity was demonstrated between the various molecular-weight forms of the normal and the mutant galactocerebrosidases by using antisera against either the high- or the low-molecular-weight enzymes. The high-molecular-weight form of galactocerebrosidase was found to possess higher specific activity toward natural substrates when compared with the low-molecular-weight form. It is suggested that the high-molecular-weight enzyme is the active form in vivo and an aggregation process that proceeds from a monomer (mol.wt. approx. 125000) to a dimer (mol.wt. approx. 250000) and from the dimer to either a tetramer (mol.wt. approx. 500000) or a hexamer (mol.wt. approx. 750000) takes place in normal as well as in Krabbe-disease tissues.


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