New insights into regulation of αIIbß3 integrin signaling by filamin A.
Res Pract Thromb Haemost
; 6(2): e12672, 2022 Feb.
Article
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| MEDLINE
| ID: mdl-35316942
ABSTRACT
Background:
Filamin (FLN) regulates many cell functions through its scaffolding activity cross-linking cytoskeleton and integrins. FLN was shown to inhibit integrin activity, but the exact mechanism remains unclear.Objectives:
The aim of this study was to evaluate the role of filamin A (FLNa) subdomains on the regulation of integrin αIIbß3 signaling.Methods:
Three FLNa deletion mutants were overexpressed in the erythro-megakaryocytic leukemic cell line HEL Del1, which lacks the N-terminal CH1-CH2 domains mediating the FLNa-actin interaction; Del2, lacking the Ig-like repeat 21, which mediates the FLNa-ß3 interaction; and Del3, lacking the C-terminal Ig repeat 24, responsible for FLNa dimerization and interaction with the small Rho guanosine triphosphatase involved in actin cytoskeleton reorganisation. Fibrinogen binding to HEL cells in suspension and talin-ß3 proximity in cells adherent to immobilized fibrinogen were assessed before and after αIIbß3 activation by the protein kinase C agonist phorbol 12-myristate 13-acetate.Results:
Our results show that FLNa-actin and FLNa-ß3 interactions negatively regulate αIIbß3 activation. Moreover, FLNa-actin interaction represses Rac activation, contributing to the negative regulation of αIIbß3 activation. In contrast, the FLNa dimerization domain, which maintains Rho inactive, was found to negatively regulate αIIbß3 outside-in signaling.Conclusion:
We conclude that FLNa negatively controls αIIbß3 activation by regulating actin polymerization and restraining activation of Rac, as well as outside-in signaling by repressing Rho.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Idioma:
En
Revista:
Res Pract Thromb Haemost
Año:
2022
Tipo del documento:
Article