Identification of Dp71 Isoforms in the Platelet Membrane Cytoskeleton

Austin, Richard C.; Fox, Joan E.B.; Werstuck, Geoff H.; Stafford, Alan R.; Bulman, Dennis E.; Dally, Ghassan Y.; Ackerley, Cameron; Weitz, Jeffrey I.; Ray, Peter N.

doi:10.1074/jbc.m203289200

Cited by 26 publications

(21 citation statements)

References 63 publications

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“…14,15 However, we report herein for the first time, to our knowledge, that platelets have GRP78 in both the membrane and the cytosol. GRP78 is translocated from the platelet membrane by shear forces, and rosuvastatin inhibits this translocation in shear-activated platelets.…”

Section: Discussionmentioning

confidence: 74%

Glucose-Regulated Protein 78 and Platelet Deposition

Molins

Peña

Padró

et al. 2010

ATVB

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Objective-To investigate the effect of rosuvastatin on platelet deposition under controlled shear rate conditions and to identify new platelet proteins involved in the interaction with the activating substrate. Methods and Results-Platelet-vessel wall interaction and thrombosis take place under dynamic conditions involving the interaction of the exposed damaged vascular wall with the circulating blood cells and proteins. Blood was perfused over type I collagen at different wall shear rates, and platelet deposition was measured by confocal microscopy. Perfused effluent blood was collected, platelets were sequentially extracted based on differential protein solubility, and proteins were separated by 2D gel electrophoresis. Blockade of 3-hydroxy-3-methylglutaryl-coenzyme A reductase significantly reduced platelet deposition and modulated the expression pattern of 18 proteins in the platelet subproteome. Among them, an increase in platelet surface 78-kDa glucose-regulated protein (GRP78), a stress-inducible multifunctional endoplasmic reticulum protein, was clearly apparent. Immunoprecipitation of platelet GRP78 revealed its interaction with tissue factor. Moreover, blockade of surface GRP78 resulted in a substantial increase in platelet deposition and tissue factor procoagulant activity and in a decrease in clotting time. Conclusion-These findings demonstrate that blockade of 3-hydroxy-3-methylglutaryl-coenzyme A reductase reduces platelet deposition and inhibits GRP78 translocation from the platelet surface after shear and collagen activation. For the first time to our knowledge, this study reports on the presence and functional role of GRP78 in platelets and indicates that GRP78 has additional functions beyond those of a molecular chaperone. Key Words: platelets Ⅲ thrombosis Ⅲ glucose-regulated protein 78 Ⅲ statins Ⅲ thrombosis Ⅲ tissue factor T he first response to vascular injury consists of platelet adhesion to the damaged vessel wall or to exposed tissue components and is mediated by flow-regulated interactions that have a key influence on subsequent thrombus growth, often culminating in life-threatening complications. 1 Clinical results strongly suggest that the beneficial effects of statins (3-hydroxy-3-methylglutaryl-coenzyme A [HMG-CoA] reductase inhibitors) may also be related to factors beyond lowering systemic lipid levels. 2,3 The effects of statins are mediated via blockade of mevalonate formation, which results in reduction of cholesterol synthesis. The inhibition of mevalonate formation also results in reduced levels of isoprenoid derivatives, which play important roles in the isoprenylation of small GTPases of the Rho/Rac/Cdc42 family. 4 -6 Isoprenylation facilitates activation and translocation of these proteins from the cytosol to the plasma membrane and thereby supports the function of these intracellular signaling pathways, which are necessary for many cellular processes in the cardiovascular system. 4,7,8 Indeed, statins inhibit cell proliferation, improve endothelial function, reduce in...

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Section: Discussionmentioning

confidence: 74%

Glucose-Regulated Protein 78 and Platelet Deposition

Molins

Peña

Padró

et al. 2010

ATVB

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“…In platelets, Dp71 and full-size utrophin were re-distributed with talin and vinculin upon binding of adhesive extracellular ligands to integrin a IIb b 3 (Earnest et al, 1995;Austin et al, 2002). However, the feasible role of Dp71 isoforms and utrophin gene products mediating the formation of focal adhesion and stress fibres was still unknown.…”

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confidence: 99%

Role of dystrophins and utrophins in platelet adhesion process

et al. 2006

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SummaryPlatelets are crucial at the site of vascular injury, adhering to the sub‐endothelial matrix through receptors on their surface, leading to cell activation and aggregation to form a haemostatic plug. Platelets display focal adhesions as well as stress fibres to contract and facilitate expulsion of growth and pro‐coagulant factors contained in the granules and to constrict the clot. The interaction of F‐actin with different actin‐binding proteins determines the properties and composition of the focal adhesions. Recently, we demonstrated the presence of dystrophin‐associated protein complex corresponding to short dystrophin isoforms (Dp71d and Dp71) and the uthophin gene family (Up400 and Up71), which promote shape change, adhesion, aggregation, and granule centralisation. To elucidate participation of both complexes during the platelet adhesion process, their potential association with integrin β‐1 fraction and the focal adhesion system (α‐actinin, vinculin and talin) was evaluated by immunofluorescence and immunoprecipitation assays. It was shown that the short dystrophin‐associated protein complex participated in stress fibre assembly and in centralisation of cytoplasmic granules, while the utrophin‐associated protein complex assembled and regulated focal adhesions. The simultaneous presence of dystrophin and utrophin complexes indicates complementary structural and signalling mechanisms to the actin network, improving the platelet haemostatic role.

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“…Furthermore, a reduced expression of Dp71 was observed in endothelial and glial cells derived from mdx fetuses and in newborn and adult mice, associated with impaired blood-brain barrier (BBB) development [46]. Finally, Dp71 association with the cell membrane was demonstrated [47], identified in the platelet membrane cytoskeleton [48], and a critical role for the clustered localization of potassium channels in retinal glial cells was described [49]. All these data suggest that the absence of all dystrophin isoforms, included Dp71, in the DMD circulating CD133 + stem cells, can lead to an impairment of the CD20-related signaling pathway, resulting in intracellular Ca 2+ overload.…”

Section: Discussionmentioning

confidence: 99%

CD20-related signaling pathway is differently activated in normal and dystrophic circulating CD133+ stem cells

Parolini

Meregalli

Belicchi

et al. 2009

Cell. Mol. Life Sci.

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Among the heterogeneous population of circulating hematopoietic and endothelial progenitors, we identified a subpopulation of CD133(+) cells displaying myogenic properties. Unexpectedly, we observed the expression of the B-cell marker CD20 in blood-derived CD133(+) stem cells. The CD20 antigen plays a role in the modulation of intracellular calcium homeostasis through signaling pathways activation. Several observations suggest that an increase in intracellular calcium concentration ([Ca(2+)](i)) could be involved in the etiology of the Duchenne muscular dystrophy (DMD). Here, we show that a CD20-related signaling pathway able to induce an increase in [Ca(2+)](i) is differently activated after brain derived neurotrophic factor (BDNF) stimulation of normal and dystrophic blood-derived CD133(+) stem cells, supporting the assumption of a "CD20-related calcium impairment" affecting dystrophic cells. Presented findings represent the starting point toward the expansion of knowledge on pathways involved in the pathology of DMD and in the behavior of dystrophic blood-derived CD133(+) stem cells.

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Identification of Dp71 Isoforms in the Platelet Membrane Cytoskeleton

Cited by 26 publications

References 63 publications

Glucose-Regulated Protein 78 and Platelet Deposition

Glucose-Regulated Protein 78 and Platelet Deposition

Role of dystrophins and utrophins in platelet adhesion process

CD20-related signaling pathway is differently activated in normal and dystrophic circulating CD133+ stem cells

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