Thromb Haemost 1997; 77(01): 150-154
DOI: 10.1055/s-0038-1655923
Platelets
Schattauer GmbH Stuttgart

Protein Tyrosine Phosphatase SHP-1 Fails to Associate with Cytoskeleton but is Normally Phosphorylated upon Thrombin Stimulation of Thrombasthenic Platelets

Ruo Ya Li
1   The Institut Fédératif de Recherche en Immunologie Cellulaire et Moléculaire, Université Paul Sabatier and Centre Hospitalo-Universitaire de Toulouse, INSERM Unité 326, Phospholipides Membranaires, Signalisation Cellulaire et Lipoproteines, Hôpital Purpan, Toulouse, France
,
Frédérique Gaits
1   The Institut Fédératif de Recherche en Immunologie Cellulaire et Moléculaire, Université Paul Sabatier and Centre Hospitalo-Universitaire de Toulouse, INSERM Unité 326, Phospholipides Membranaires, Signalisation Cellulaire et Lipoproteines, Hôpital Purpan, Toulouse, France
,
Jeannie M F Ragab-Thomas
1   The Institut Fédératif de Recherche en Immunologie Cellulaire et Moléculaire, Université Paul Sabatier and Centre Hospitalo-Universitaire de Toulouse, INSERM Unité 326, Phospholipides Membranaires, Signalisation Cellulaire et Lipoproteines, Hôpital Purpan, Toulouse, France
,
Jacques Maclouf
2   INSERM Unite 348, Physiopathologie Cellulaire et Moléculaire des Cellules du Sang et des Vaisseaux, Hôpital Lariboisiére, Paris
,
Jacques P Caen
3   Institut des Vaisseaux et du Sang, Hôpital Lariboisiére, Paris, France
,
Sylviane Lévy-Toledano
2   INSERM Unite 348, Physiopathologie Cellulaire et Moléculaire des Cellules du Sang et des Vaisseaux, Hôpital Lariboisiére, Paris
,
Hugues Chap
1   The Institut Fédératif de Recherche en Immunologie Cellulaire et Moléculaire, Université Paul Sabatier and Centre Hospitalo-Universitaire de Toulouse, INSERM Unité 326, Phospholipides Membranaires, Signalisation Cellulaire et Lipoproteines, Hôpital Purpan, Toulouse, France
› Author Affiliations
Further Information

Publication History

Received 08 August 1996

Accepted after revision 08 October 1996

Publication Date:
11 July 2018 (online)

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Summary

SHP-1 is a cytoplasmic protein tyrosine phosphatase predominantly expressed in hematopoietic cells. Upon thrombin stimulation of human platelets, SHP-1 is rapidly phosphorylated on both serine and tyrosine residues, and becomes associated with the cytoskeleton, where it could participate in the formation of multiprotein signalling complexes. In order to discriminate between signalling events occurring downstream of G-protein-coupled thrombin receptor and those subsequent to integrin αIIbβ3engagement, SHP-1 behaviour was examined in platelets from two patients lacking integrin αIIbβ3 (Glanzmann’s thrombasthenia). Upon thrombin stimulation, phosphorylation of SHP-1 occurred normally in thrombasthenic platelets, whereas association with the cytoskeleton was abolished. Moreover, inhibition of normal platelet aggregation with the tetrapeptide arg-gly-asp-ser (RGDS), which impairs fibrinogen binding to integrin aIIb(33, did not alter significantly SHP-1 phosphorylation. It is concluded that SHP-1 phosphorylation is not a consequence of integrin signalling but might rather occur downstream of thrombin receptor and heterotrimeric G-proteins.