© 1997 American Heart Association, Inc.
Articles |
Evidence for an 
-Granular Pool of the Cytoskeletal Protein -Actinin in Human Platelets That Redistributes With the Adhesive Glycoprotein Thrombospondin-1 During the Exocytotic Process
From Unité INSERM 353, Hôpital Saint-Louis, Paris (V.D., C.L.), and Centre de Recherches sur le Sang et les Vaisseaux de l'Association Claude Bernard, Hôpital Lariboisière, Paris (V.D.); and Laboratoire de Microscopie Electronique, Faculté de Médecine, Tours, France (B.B.A., M.B.L.).
Correspondence to Dr Véronique Dubernard, Unité INSERM 353, Hôpital Saint-Louis, 1, avenue Claude Vellefaux, 75010-Paris, France.
Abstract In a previous study, we have demonstrated that the
platelet adhesive glycoprotein thrombospondin-1 (TSP-1)
interacts specifically with the cytoskeletal protein -actinin in a
solid-phase binding assay. Stored in the -granules of platelets,
TSP-1 is secreted during cell activation and binds to the plasma
membrane promoting the platelet macroaggregate formation. However,
the molecular mechanism by which TSP-1 reaches and binds to the
platelet surface is to date unelucidated. -Actinin is an
actin-binding and actinin–cross-linking protein that is present in
most cells and may act as a link between the bundles of F-actin and the
plasma membrane. In this study, we have investigated a possible
interaction of -actinin with TSP-1 in platelets by examining
their respective subcellular location during the platelet
activation process. By indirect immunofluorescence,
-actinin was found to display a granular staining in resting
platelets similar to that of TSP-1. Performing postembedding
immunogold labeling for electron microscopy, we detected the presence
of -actinin throughout the cytoplasm, but the strongest gold
staining was found in organelles identified as -granules on the
basis of their ultrastructure and TSP-1 content. With the use of double
immunogold labeling on platelets at different stages of activation
by thrombin, both -actinin and TSP-1 were seen redistributing from
the -granules to the platelet surface via the open
canalicular system (OCS). At the same time, the
cytoplasmic -actinin concentrated toward the plasma membrane, but no
colocalization with the F-actin bundles was evidenced. Finally,
preembedding immunogold labeling and immunoprecipitation of
125I-surface–labeled, thrombin-activated
platelets further demonstrated that -actinin was expressed on
the plasma membrane in the absence of any detectable expression of
actin and that it could form molecular complexes with TSP-1 on
activated platelets. These results suggest that -actinin
found to be present on the platelet surface together with TSP-1
originates in the -granules by fusion of the -granules with the
plasma membrane during platelet exocytosis.
Key Words: thrombospondin-1 • -actinin • -granule • platelet exocytosis • molecular complexes
This article has been cited by other articles:
 |
|
 |
|
  I. K. Kandela, R. Bleher, and R. M. Albrecht Multiple Correlative Immunolabeling for Light and Electron Microscopy Using Fluorophores and Colloidal Metal Particles J. Histochem. Cytochem., October 1, 2007; 55(10): 983 - 990. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. I. Zwicker, F. Peyvandi, R. Palla, R. Lombardi, M. T. Canciani, A. Cairo, D. Ardissino, L. Bernardinelli, K. A. Bauer, J. Lawler, et al. The thrombospondin-1 N700S polymorphism is associated with early myocardial infarction without altering von Willebrand factor multimer size Blood, August 15, 2006; 108(4): 1280 - 1283. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Bonnefoy, K. Daenens, H. B. Feys, R. De Vos, P. Vandervoort, J. Vermylen, J. Lawler, and M. F. Hoylaerts Thrombospondin-1 controls vascular platelet recruitment and thrombus adherence in mice by protecting (sub)endothelial VWF from cleavage by ADAMTS13 Blood, February 1, 2006; 107(3): 955 - 964. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Saumet, M. B. Slimane, M. Lanotte, J. Lawler, and V. Dubernard Type 3 repeat/C-terminal domain of thrombospondin-1 triggers caspase-independent cell death through CD47/{alpha}v{beta}3 in promyelocytic leukemia NB4 cells Blood, July 15, 2005; 106(2): 658 - 667. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. A. Coppinger, G. Cagney, S. Toomey, T. Kislinger, O. Belton, J. P. McRedmond, D. J. Cahill, A. Emili, D. J. Fitzgerald, and P. B. Maguire Characterization of the proteins released from activated platelets leads to localization of novel platelet proteins in human atherosclerotic lesions Blood, March 15, 2004; 103(6): 2096 - 2104. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. P. Rastaldi, S. Armelloni, S. Berra, M. Li, M. Pesaresi, H. Poczewski, B. Langer, D. Kerjaschki, A. Henger, S. M. Blattner, et al. Glomerular Podocytes Possess the Synaptic Vesicle Molecule Rab3A and Its Specific Effector Rabphilin-3a Am. J. Pathol., September 1, 2003; 163(3): 889 - 899. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. J. Barkalow, K. L. Barkalow, and T. N. Mayadas Dimerization of P-selectin in platelets and endothelial cells Blood, November 1, 2000; 96(9): 3070 - 3077. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. Nguyen, M. E. Carbajal, and M. L. Vitale Intracellular Mechanisms Involved in Dopamine-Induced Actin Cytoskeleton Organization and Maintenance of a Round Phenotype in Cultured Rat Lactotrope Cells Endocrinology, August 1, 1999; 140(8): 3467 - 3477. [Abstract] [Full Text]
|
|