The Lysosomal Granule Membrane Protein, Lamp-2, Is also Present in Platelet Dense Granule Membranes

1996 ◽  
Vol 75 (04) ◽  
pp. 623-629 ◽  
Author(s):  
S J Israels ◽  
E M McMillan ◽  
C Robertson ◽  
S Singhroy ◽  
A McNicol
Keyword(s):  
Membrane Protein ◽  
Cell Types ◽  
Surface Expression ◽  
Dense Granule ◽  
Similar Distribution ◽  
Dense Granules ◽  
Granule Membrane ◽  
Early Expression ◽  
Late Expression ◽  
Granule Release

SummaryLysosomal Associated Membrane Protein-2 (LAMP-2) is an inherent component of lysosomal granule membranes in diverse cell types, including platelets. We examined platelets for evidence of LAMP-2 in dense granule membranes as CD63 has previously been shown to be present in both lysosomal and dense granule membranes. Immunological techniques were used to examine the localization of LAMP-2 in control platelets and those from an individual with Hermansky-Pudlak syndrome (HPS), a condition characterised by platelet dense granule deficiency. Immunoblotting studies demonstrated that LAMP-2 was enriched in a dense granule preparation. Flow cytometry of thrombin-stimulated control platelets was consistent with biphasic surface expression of LAMP-2. The early expression was accompanied by dense granule, but minimal lysosomal granule, release. The late expression was accompanied by additional lysosomal granule release only. Thrombin stimulation of HPS platelets showed only late, lysosome-associated LAMP-2 expression. Immunoelectron microscopy indicated the presence of LAMP-2 in the membranes of serotonin-containing granules as identified by an anti-serotonin polyclonal antibody. These data indicate that LAMP-2 is present in the membranes of platelet dense granules in addition to lysosomal granules, and has a similar distribution to CD63.

scholarly journals Identification of a platelet dense granule membrane protein that is deficient in a patient with the Hermansky-Pudlak syndrome

Blood ◽  
1991 ◽  
Vol 77 (1) ◽  
pp. 101-112 ◽  
Author(s):  
JM Gerrard ◽  
D Lint ◽  
PJ Sims ◽  
T Wiedmer ◽  
RD Fugate ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Western Blot ◽  
Protein S ◽  
Dense Granule ◽  
Western Blots ◽  
Dense Granules ◽  
Granule Membrane ◽  
Thrombin Activation ◽  
Hermansky Pudlak Syndrome ◽  
Slot Blot Analysis

Abstract Monoclonal antibodies were raised after injecting mice with isolated human dense granules. Several of these monoclonals were found to recognize a 40-Kd dense granule membrane protein. Western blot and immunofluorescent analysis confirmed the dense-granule specificity. After thrombin activation, the protein was found in patches on the external platelet membrane. By Western blot and slot blot analysis, the protein was found to be markedly deficient in a patient with the Hermansky-Pudlak syndrome. Studies of neutrophils and endothelial cells show the presence of immunologically related granule-membrane protein(s). Western blots using four anti-synaptophysin antibodies and three antibodies to the platelet 40-Kd protein suggest that the protein may share some homology with, but is not identical to, the synaptosomal membrane protein synaptophysin.

scholarly journals Identification of a platelet dense granule membrane protein that is deficient in a patient with the Hermansky-Pudlak syndrome

Blood ◽  
1991 ◽  
Vol 77 (1) ◽  
pp. 101-112 ◽  
Author(s):  
JM Gerrard ◽  
D Lint ◽  
PJ Sims ◽  
T Wiedmer ◽  
RD Fugate ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Western Blot ◽  
Protein S ◽  
Dense Granule ◽  
Western Blots ◽  
Dense Granules ◽  
Granule Membrane ◽  
Thrombin Activation ◽  
Hermansky Pudlak Syndrome ◽  
Slot Blot Analysis

Monoclonal antibodies were raised after injecting mice with isolated human dense granules. Several of these monoclonals were found to recognize a 40-Kd dense granule membrane protein. Western blot and immunofluorescent analysis confirmed the dense-granule specificity. After thrombin activation, the protein was found in patches on the external platelet membrane. By Western blot and slot blot analysis, the protein was found to be markedly deficient in a patient with the Hermansky-Pudlak syndrome. Studies of neutrophils and endothelial cells show the presence of immunologically related granule-membrane protein(s). Western blots using four anti-synaptophysin antibodies and three antibodies to the platelet 40-Kd protein suggest that the protein may share some homology with, but is not identical to, the synaptosomal membrane protein synaptophysin.

scholarly journals Platelet dense granule membranes contain both granulophysin and P- selectin (GMP-140)

Blood ◽  
1992 ◽  
Vol 80 (1) ◽  
pp. 143-152 ◽  
Author(s):  
SJ Israels ◽  
JM Gerrard ◽  
YV Jacques ◽  
A McNicol ◽  
B Cham ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Serotonin Release ◽  
Dense Granule ◽  
Double Labeling ◽  
Platelet Surface ◽  
Thin Sections ◽  
Dense Granules ◽  
Granule Membrane ◽  
Dense Granule Secretion

We recently reported the characterization of a platelet granule membrane protein of molecular weight (mol wt) 40,000 called granulophysin (Gerrard et al: Blood 77:101, 1991), identified by a monoclonal antibody (MoAb D545) raised to purified dense granule membranes. Using immunoelectron-microscopic techniques on frozen thin sections, this protein was localized in resting and thrombin-stimulated platelets. In resting platelets, labeled with antigranulophysin antibodies and immunogold probes, label was localized to the membranes of one or two clear granules per platelet thin section. D545 also labeled dense granules in permeabilized whole platelets and isolated dense granule preparations examined by whole-mount techniques. Expression of granulophysin on the platelet surface paralleled dense granule secretion as measured by 14C-serotonin release under conditions in which lysosomal granule release, as measured by beta-glucuronidase secretion, was less than 5%. After thrombin stimulation, both the surface-connected canalicular system and the plasma membrane were labeled, demonstrating redistribution of granulophysin associated with degranulation. Double labeling experiments with D545 and antibodies to the alpha-granule membrane protein, P-selectin, demonstrated labeling of both P-selectin and granulophysin on dense granule membranes. Distribution of both proteins on the plasma membrane after platelet stimulation was similar. The results demonstrate that granulophysin is localized to the dense granules of platelets and is redistributed to the plasma membrane after platelet activation.

scholarly journals Platelet dense granule membranes contain both granulophysin and P- selectin (GMP-140)

Blood ◽  
1992 ◽  
Vol 80 (1) ◽  
pp. 143-152 ◽  
Author(s):  
SJ Israels ◽  
JM Gerrard ◽  
YV Jacques ◽  
A McNicol ◽  
B Cham ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Serotonin Release ◽  
Dense Granule ◽  
Double Labeling ◽  
Platelet Surface ◽  
Thin Sections ◽  
Dense Granules ◽  
Granule Membrane ◽  
Dense Granule Secretion

Abstract We recently reported the characterization of a platelet granule membrane protein of molecular weight (mol wt) 40,000 called granulophysin (Gerrard et al: Blood 77:101, 1991), identified by a monoclonal antibody (MoAb D545) raised to purified dense granule membranes. Using immunoelectron-microscopic techniques on frozen thin sections, this protein was localized in resting and thrombin-stimulated platelets. In resting platelets, labeled with antigranulophysin antibodies and immunogold probes, label was localized to the membranes of one or two clear granules per platelet thin section. D545 also labeled dense granules in permeabilized whole platelets and isolated dense granule preparations examined by whole-mount techniques. Expression of granulophysin on the platelet surface paralleled dense granule secretion as measured by 14C-serotonin release under conditions in which lysosomal granule release, as measured by beta-glucuronidase secretion, was less than 5%. After thrombin stimulation, both the surface-connected canalicular system and the plasma membrane were labeled, demonstrating redistribution of granulophysin associated with degranulation. Double labeling experiments with D545 and antibodies to the alpha-granule membrane protein, P-selectin, demonstrated labeling of both P-selectin and granulophysin on dense granule membranes. Distribution of both proteins on the plasma membrane after platelet stimulation was similar. The results demonstrate that granulophysin is localized to the dense granules of platelets and is redistributed to the plasma membrane after platelet activation.

scholarly journals Identification of lysosome-associated membrane protein-2 as an activation-dependent platelet surface glycoprotein

Blood ◽  
1992 ◽  
Vol 80 (6) ◽  
pp. 1470-1475 ◽  
Author(s):  
RL Silverstein ◽  
M Febbraio
Keyword(s):  
Membrane Protein ◽  
Surface Membrane ◽  
Integral Membrane Protein ◽  
Surface Expression ◽  
Lysosomal Membrane ◽  
Surface Glycoprotein ◽  
Resting Cells ◽  
Binding Studies ◽  
Platelet Surface ◽  
Dense Granules

Platelets undergo biochemical and morphologic changes when stimulated that greatly alter their function and contribute to their role in thrombosis and hemostasis. We recently identified and cloned the cDNA for a platelet surface glycoprotein expressed on activated, not resting cells. We found that this protein, lysome-associated membrane protein-1 (LAMP-1), is an integral membrane protein of the lysosome that translocated to the surface membrane when platelets were stimulated by a strong agonist. We now show with immunofluorescence flow cytometry that LAMP-2, a lysosomal membrane protein that shares approximately 30% homology with LAMP-1, is also expressed preferentially on the surface of activated platelets. Equilibrium binding studies with 125I-anti-LAMP- 2 IgG showed approximately 1,100 binding sites per thrombin-stimulated platelet and less than 50 per resting platelet. Sucrose gradient ultracentrifugation fractionation of resting platelet sonicates showed that LAMP-2 colocalized with LAMP-1 and with lysosomal enzymes, and not with thrombospondin or serotonin, which are markers of the two other platelet granule compartments, alpha-granules and dense granules. LAMP- 2 surface expression was minimal in response to platelet stimulation by weak agonists such as epinephrine and ADP. These data show that LAMP-2, like LAMP-1, translocates from the lysosomal membrane compartment to the surface membrane when platelets are activated. Regulated surface expression of these heavily glycosylated proteins may play a role in the adhesive, prothrombotic phenotype of these cells.

scholarly journals Platelet and Megakaryocyte Dense Granules Contain Glycoproteins Ib and IIb-IIIa

Blood ◽  
1997 ◽  
Vol 89 (11) ◽  
pp. 4047-4057 ◽  
Author(s):  
Tayebeh Youssefian ◽  
Jean-Marc Massé ◽  
Francine Rendu ◽  
Josette Guichard ◽  
Elisabeth M. Cramer
Keyword(s):  
Plasma Membrane ◽  
Dense Body ◽  
Secretory Granules ◽  
Dense Granule ◽  
Immunogold Labeling ◽  
Membrane Receptors ◽  
Thin Sections ◽  
Dense Granules ◽  
Granule Membrane ◽  
Plasma Membrane Receptors

Abstract Platelets contain two main types of secretory organelles, the dense granules and the α-granules. P-selectin, a specific receptor for leukocytes that is present in the α-granule membrane, has also been demonstrated to be associated with the dense granule limiting membrane, showing that a relationship exists between these two types of secretory granules. We have previously shown that the plasma membrane receptors glycoproteins (Gp) IIb-IIIa and Ib are also present in the α-granule membrane. To document further the composition of the dense granule membrane, we have used immunoelectron microscopy in the present work to determine if the dense granule membrane also contains these glycoproteins. First, the cytochemical method of Richards and Da Prada (J Histochem Cytochem 25:1322, 1977), which specifically enhances dense body electron density, was combined with immunogold-labeled anti–Gp IIb-IIIa or anti–Gp Ib antibody. A consistent and reproducible labeling for Gp IIb-IIIa, but less for Gp Ib, was found in the membrane of platelet dense granules. Subsequently, double immunogold labeling was performed on frozen thin sections of resting platelets using antibodies directed against the dense body components granulophysin or P-selectin, followed by anti–Gp IIb-IIIa or anti–Gp Ib. Consistent labeling for Gp IIb-IIIa and weaker labeling for Gp Ib were detected in dense bodies. The possibility that the granulophysin-positive structures could be lysosomes was excluded by the presence of P-selectin. Immunogold labeling of isolated dense granule fractions confirmed these results. Identical findings were made on human cultured megakaryocytes using double immunolabeling. In conclusion, this study demonstrates the presence of Gp IIb-IIIa and Gp Ib on the dense granule membrane. This observation provides additionnal evidence of similarities between the α-granule and dense granule membranes and raises the possibility of a dual mechanism responsible for the formation of dense granules similar to that of α-granules, ie, endogenous synthesis as well as endocytosis from the plasma membrane.

scholarly journals TPC2 mediates new mechanisms of platelet dense granule membrane dynamics through regulation of Ca2+release

2015 ◽  
Vol 26 (18) ◽  
pp. 3263-3274 ◽  
Author(s):  
Andrea L. Ambrosio ◽  
Judith A. Boyle ◽  
Santiago M. Di Pietro
Keyword(s):  
Dense Granule ◽  
Membrane Dynamics ◽  
Vesicular Trafficking ◽  
Pore Channel ◽  
Calcium Stores ◽  
Dense Granules ◽  
Granule Membrane ◽  
Specific Proteins ◽  
Normal Hemostasis ◽  
First Time

Platelet dense granules (PDGs) are acidic calcium stores essential for normal hemostasis. They develop from late endosomal compartments upon receiving PDG-specific proteins through vesicular trafficking, but their maturation process is not well understood. Here we show that two-pore channel 2 (TPC2) is a component of the PDG membrane that regulates PDG luminal pH and the pool of releasable Ca2+. Using a genetically encoded Ca2+biosensor and a pore mutant TPC2, we establish the function of TPC2 in Ca2+release from PDGs and the formation of perigranular Ca2+nanodomains. For the first time, Ca2+spikes around PDGs—or any organelle of the endolysosome family—are visualized in real time and revealed to precisely mark organelle “kiss-and-run” events. Further, the presence of membranous tubules transiently connecting PDGs is revealed and shown to be dramatically enhanced by TPC2 in a mechanism that requires ion flux through TPC2. “Kiss-and-run” events and tubule connections mediate transfer of membrane proteins and luminal content between PDGs. The results show that PDGs use previously unknown mechanisms of membrane dynamics and content exchange that are regulated by TPC2.

scholarly journals Cardiopulmonary bypass induces leukocyte-platelet adhesion

Blood ◽  
1992 ◽  
Vol 79 (5) ◽  
pp. 1201-1205 ◽  
Author(s):  
CS Rinder ◽  
JL Bonan ◽  
HM Rinder ◽  
J Mathew ◽  
R Hines ◽  
...  
Keyword(s):  
Cardiopulmonary Bypass ◽  
Time Course ◽  
Platelet Adhesion ◽  
Surface Expression ◽  
Cd11b Expression ◽  
Activated Platelets ◽  
Granule Membrane ◽  
Time Courses ◽  
Granule Release

Abstract Cardiopulmonary bypass (CPB) has been demonstrated to activate platelets, producing an increased number of circulating platelets that have undergone alpha-granule release and express granule membrane protein-140 (GMP-140) on their surface. In vitro, GMP-140 mediates activated platelet adhesion to neutrophils (PMN) and monocytes, causing the formation of leukocyte-platelet conjugates. Using a newly developed assay that measures the percentage of circulating leukocyte-platelet conjugates in whole blood, we studied 17 patients undergoing CPB and have determined that (1) monocyte-platelet conjugates increased significantly during CPB, from 18% +/- 1.5% to 44% +/- 4.5% (mean +/- SEM) by the end of CPB, while PMN-platelet conjugates increased only slightly and lymphocyte-platelet conjugates decreased; (2) the time course of the increase in monocyte- and PMN-platelet conjugates paralleled that of the increase in circulating activated platelets, as determined by the presence of surface GMP-140; and (3) monocyte activation, as assessed by increased surface expression of CD11b, showed a gradual increase similar to the increase in monocyte-platelet conjugates, while PMN surface CD11b peaked immediately after the start of CPB. We conclude that CPB, through increased platelet GMP-140 expression, causes formation of monocyte-platelet, and to a lesser extent, PMN-platelet conjugates. The activation of monocytes and PMN on CPB, as evidenced by CD11b expression, occurs with differing time courses.

A Light and Electron Microscopic Study of a Normal Adrenal Medulla and a Pheochromocytoma from a Horse

1979 ◽  
Vol 16 (4) ◽  
pp. 395-404 ◽  
Author(s):  
H. Gelberg ◽  
G. L. Cockerell ◽  
R. R. Minor
Keyword(s):  
Tumor Cells ◽  
Adrenal Medulla ◽  
Secretory Granules ◽  
Cell Types ◽  
Electron Microscopic ◽  
Dense Granules ◽  
Granule Membrane ◽  
Membrane Bound ◽  
Vascular Channels ◽  
Electron Lucent

The outer medullary (juxtacortical) zone of a normal equine adrenal gland had columnar chromaffin-positive cells arranged with their long axes perpendicular to fine vascular channels. The deeper medullary regions were composed of smaller irregularly round to polygonal chromaffin positive cells in small packets. Both cell types contained two types of membrane-bound cytoplasmic secretory granules. Osmiophilic granules with a homogeneous core, crenated membrane and narrow submembranous halo predominated in the columnar juxtacortical cells. The rounder, central medullary cells contained predominantly electron dense granules with a wide irregular electron lucent space between an eccentric core and the granule membrane. In contrast, irrespective of cell type or zone, cells from a pheochromocytoma contained only one type of granule similar to that described for the juxtacortical region of the normal equine adrenal medulla. The tumor cells could be classified into three subtypes based on density of granule packing but the granules were morphologically similar in all tumor cells.

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