Small GTP-binding protein RalA associates with Weibel-Palade bodies in endothelial cells.
Thromb Haemost
; 82(3): 1177-81, 1999 Sep.
Article
en En
| MEDLINE
| ID: mdl-10494784
In endothelial cells von Willebrand factor (vWF) and P-selectin are stored in dense granules. so-called Weibel-Palade bodies. Upon stimulation of endothelial cells with a variety of agents including thrombin, these organelles fuse with the plasma membrane and release their content. Small GTP-binding proteins have been shown to control release from intracellular storage pools in a number of cells. In this study we have investigated whether small GTP-binding proteins are associated with Weibel-Palade bodies. We isolated Weibel-Palade bodies by centrifugation on two consecutive density gradients of Percoll. The dense fraction in which these subcellular organelles were highly enriched, was analysed by SDS-PAGE followed by GTP overlay. A distinct band with an apparent molecular weight of 28,000 was observed. Two-dimensional gel electrophoresis followed by GTP overlay revealed the presence of a single small GTP-binding protein with an isoelectric point of 7.1. A monoclonal antibody directed against RalA showed reactivity with the small GTP-binding protein present in subcellular fractions that contain Weibel-Palade bodies. The small GTPase RalA was previously identified on dense granules of platelets and on synaptic vesicles in nerve terminals. Our observations suggest that RalA serves a role in regulated exocytosis of Weibel-Palade bodies in endothelial cells.
Buscar en Google
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Endotelio Vascular
/
Cuerpos de Weibel-Palade
/
Proteínas de Unión al GTP ral
/
GTP Fosfohidrolasas
Tipo de estudio:
Prognostic_studies
/
Risk_factors_studies
Límite:
Humans
Idioma:
En
Revista:
Thromb Haemost
Año:
1999
Tipo del documento:
Article
País de afiliación:
Países Bajos
Pais de publicación:
Alemania