The alpha 4 beta 1 fibronectin ligands CS-1, Hep II, and RGD induce different intracellular events in B lymphoid cells. Comparison with the effects of the endothelial ligand VCAM-1.
Cell Adhes Commun
; 4(4-5): 251-67, 1996 Nov.
Article
em En
| MEDLINE
| ID: mdl-9117345
ABSTRACT
The lymphocyte integrin alpha 4 beta 1 is the receptor for the Hep II domain and CS-1 site in fibronectin (Fn) as well as for VCAM-1. We recently showed that upon activation with anti-beta 1 mAb TS2/16, alpha 4 beta 1 also recognizes the RGD Fn sequence. To determine the physiological role of these multiple interactions, we have now studied some intracellular events induced by "resting" and activated alpha 4 beta 1 binding to its different ligands. Analyses of actin and tubulin reorganization upon adhesion of B lymphoid cells to Fn fragments or VCAM-1 showed that VCAM-1, a 38 kDa fragment (Hep II+CS-1), and the CS-1 synthetic peptide induced formation of transient cytoplasmic projections; however, cells attached to a 58 kDa (Hep II) or 80 kDa (RGD) fragments remained rounded. Using transfilter assays, we showed that VCAM-1, 38 kDa and CS-1 also induced dose-dependent B cell migration mediated by alpha 4 beta 1. Furthermore, these three ligands, but not the 80 kDa fragment or a synthetic peptide (H1) containing a sequence from Hep II shown to bind alpha 4 beta 1, induced tyrosine phosphorylation of a 110 kDa protein. Activation of alpha 4 beta 1 with TS2/16 inhibited the cytoplasmic protrusions and cell migration but did not affect the pattern of phosphorylation. Our results indicate that the various alpha 4 beta 1 ligands induce different cellular responses. Most importantly they show that alpha 4 beta 1 interaction with CS-1 is sufficient to trigger intracellular events in B cells. Furthermore, they suggest a regulation by the activation form of the receptor as well as by the ligand in events involving lymphocyte adhesion and migration.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Linfócitos B
/
Integrinas
/
Receptores de Retorno de Linfócitos
/
Fibronectinas
/
Molécula 1 de Adesão de Célula Vascular
/
Proteínas do Citoesqueleto
Limite:
Humans
Idioma:
En
Revista:
Cell Adhes Commun
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
1996
Tipo de documento:
Article
País de afiliação:
Espanha