Structural analysis of receptors and actin polarity in platelet protrusions.
Proc Natl Acad Sci U S A
; 118(37)2021 09 14.
Article
em En
| MEDLINE
| ID: mdl-34504018
ABSTRACT
During activation the platelet cytoskeleton is reorganized, inducing adhesion to the extracellular matrix and cell spreading. These processes are critical for wound healing and clot formation. Initially, this task relies on the formation of strong cellular-extracellular matrix interactions, exposed in subendothelial lesions. Despite the medical relevance of these processes, there is a lack of high-resolution structural information on the platelet cytoskeleton controlling cell spreading and adhesion. Here, we present in situ structural analysis of membrane receptors and the underlying cytoskeleton in platelet protrusions by applying cryoelectron tomography to intact platelets. We utilized three-dimensional averaging procedures to study receptors at the plasma membrane. Analysis of substrate interaction-free receptors yielded one main structural class resolved to 26 Å, resembling the αIIbß3 integrin folded conformation. Furthermore, structural analysis of the actin network in pseudopodia indicates a nonuniform polarity of filaments. This organization would allow generation of the contractile forces required for integrin-mediated cell adhesion.
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Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Plaquetas
/
Citoesqueleto de Actina
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Membrana Celular
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Actinas
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Complexo Glicoproteico GPIIb-IIIa de Plaquetas
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Extensões da Superfície Celular
Limite:
Humans
Idioma:
En
Ano de publicação:
2021
Tipo de documento:
Article