Endotoxin-induced platelet aggregation and secretion. II. Changes in plasma membrane proteins

Responses of blood platelets to bacterial endotoxin lipopolysaccharide (LPS) have been correlated with changes in the molecular organization and composition of the platelet plasma membrane proteins. Binding of LPS, which occurred in the absence of Ca2+, was distinguished from platelet aggregation and degranulation, which required Ca2+ and plasma proteins. Changes in membrane organization were detected by double-labelling with [125I] and [131I] iodide, mediated by lactoperoxidase and hydrogen peroxide. Changes in total membrane composition were detected by gel electrophoresis of isolated membranes. Binding of LPS was associated with increased accessibility of a protein of mol. wt. 80000 to iodination. After aggregation and degranulation there was, in addition, increased accessibility of proteins of mol. wt. 68000 and 48000. Isolated membranes from LPS-stimulated platelets contained more of a protein of mol. wt. 200000 and less of a protein of mol. wt. 220000 than control membranes prepared from unstimulated platelets in the presence of cAMP and aminophylline. The relationship of the modified plasma membrane proteins to the contractile proteins of the platelet and their possible redistribution in the cell during aggregation and secretion is discussed.

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Separate Mechanisms for the Inhibition of Platelet Aggregation by Adenosine and 2-Cloroadenosine

10.1055/s-0039-1680638 ◽

1977 ◽

Author(s):

R. Apitz-Castro ◽

C.R. Torres

Keyword(s):

Plasma Membrane ◽

Platelet Aggregation ◽

Membrane Proteins ◽

Plasma Membranes ◽

Electrophoretic Pattern ◽

Membrane Component ◽

Plasma Membrane Proteins ◽

Adp Receptor ◽

Selective Increase ◽

Specific Membrane

The mechanism by which adenosine (Ado) and 2-cloroadenosine (Cl-Ado) inhibit platelet aggregation is not clear. In order to get some insight into the mode of action of these compounds, we studied the effect of Cl-Ado on the uptake of Ado by intact platelets, the effect of these compounds on the endogenous phosphorylation of specific plasma membrane proteins, and its effect on the carboxymethylation pattern of plasma membrane proteins in intact platelets. Cl-Ado does not modify the uptake of Ado by intact platelets, nor is itself incorporated into the platelet’s pool of nucleotides. Phosphorylation of plasma membrane proteins is not affected by Cl-Ado; however, Ado produces a selective increase in the phosphorylation of one plasma membrane component of glycoproteic nature. As has been reported, phosphorylation of this glycoprotein is also modulated by cAMP (BBA, 455:371, 1976). Although the electrophoretic pattern of carboxymethylated plasma membranes is unaffected by Ado or Cl-Ado, it was found that the former markedly increases the label of all the susceptible proteins, while Cl-Ado selectively protects a single membrane component. Electrophoretically, this component seems to be related to the above mentioned glycoprotein. The results reported suggest that Ado and Cl-Ado interact with different components of the plasma membrane, impairing platelet aggregation through different mechanisms. In the case of Ado, two ways seem operative: a) A cAMP-like stimulation of a specific membrane glycoprotein and b) A more general perturbation of the membrane structure, perhaps through an Ado-carrier complex (Acta Med. Scand. 525:169, 1971). Cl-Ado seems to interact solely on the external surface of the plasma membrane, suggesting that the transmembrane phospho-glycoprotein previously described is in some way closely related to the ADP-receptor of the platelet plasma membrane.

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Detergent fractionation with subsequent subtractive suppression hybridization as a tool for identifying genes coding for plasma membrane proteins

Experimental Dermatology ◽

10.1111/j.1600-0625.2008.00821.x ◽

2009 ◽

Vol 18 (6) ◽

pp. 527-535 ◽

Cited By ~ 2

Author(s):

Andreas Lange ◽

Claudia Kistler ◽

Tanja B. Jutzi ◽

Alexandr V. Bazhin ◽

Claus Detlev Klemke ◽

...

Keyword(s):

Plasma Membrane ◽

Membrane Proteins ◽

Plasma Membrane Proteins ◽

Subtractive Suppression Hybridization

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Evidence That Type I, II, and III Inositol 1,4,5-Trisphosphate Receptors Can Occur as Integral Plasma Membrane Proteins

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)61534-6 ◽

2000 ◽

Vol 275 (35) ◽

pp. 27488-27493

Author(s):

Akihiko Tanimura ◽

Yosuke Tojyo ◽

R. James Turner

Keyword(s):

Plasma Membrane ◽

Membrane Proteins ◽

Type I ◽

Plasma Membrane Proteins ◽

Inositol 1,4,5 Trisphosphate

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pH-dependent Cargo Sorting from the Golgi

Journal of Biological Chemistry ◽

10.1074/jbc.m110.197889 ◽

2011 ◽

Vol 286 (12) ◽

pp. 10058-10065 ◽

Cited By ~ 34

Author(s):

Chunjuan Huang ◽

Amy Chang

Keyword(s):

Plasma Membrane ◽

Membrane Proteins ◽

Atpase Activity ◽

Secretory Pathway ◽

Ph Dependence ◽

Glucose Deprivation ◽

Ph Homeostasis ◽

Plasma Membrane Proteins ◽

Cytosolic Ph ◽

Cargo Sorting

The vacuolar proton-translocating ATPase (V-ATPase) plays a major role in organelle acidification and works together with other ion transporters to maintain pH homeostasis in eukaryotic cells. We analyzed a requirement for V-ATPase activity in protein trafficking in the yeast secretory pathway. Deficiency of V-ATPase activity caused by subunit deletion or glucose deprivation results in missorting of newly synthesized plasma membrane proteins Pma1 and Can1 directly from the Golgi to the vacuole. Vacuolar mislocalization of Pma1 is dependent on Gga adaptors although no Pma1 ubiquitination was detected. Proper cell surface targeting of Pma1 was rescued in V-ATPase-deficient cells by increasing the pH of the medium, suggesting that missorting is the result of aberrant cytosolic pH. In addition to mislocalization of the plasma membrane proteins, Golgi membrane proteins Kex2 and Vrg4 are also missorted to the vacuole upon loss of V-ATPase activity. Because the missorted cargos have distinct trafficking routes, we suggest a pH dependence for multiple cargo sorting events at the Golgi.

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