Protein kinase C regulates alpha v beta 5-dependent cytoskeletal associations and focal adhesion kinase phosphorylation.
J Cell Biol
; 134(5): 1323-32, 1996 Sep.
Article
em En
| MEDLINE
| ID: mdl-8794871
ABSTRACT
Integrins alpha v beta 3 and alpha v beta 5 both mediate cell adhesion to vitronectin yet trigger different postligand binding events. Integrin alpha v beta 3 is able to induce cell spreading, migration, angiogenesis, and tumor metastasis without additional stimulators, whereas alpha v beta 5 requires exogenous activation of protein kinase C (PKC) to mediate these processes. To investigate this difference, the ability of beta 3 or beta 5 to induce colocalization of intracellular proteins was assessed by immunofluorescence in hamster CS-1 melanoma cells. We found that alpha v beta 5 induced colocalization of talin, alpha-actinin, tensin, and actin very weakly relative to alpha v beta 3. alpha v beta 5 was able to efficiently induce colocalization of focal adhesion kinase (FAK); however, it was unable to increase phosphorylation of FAK on tyrosine. Activation of PKC by adding phorbol ester to alpha v beta 5-expressing cells induced spreading, increased colocalization of alpha-actinin, tensin, vinculin, p130cas and actin, and triggered tyrosine phosphorylation of FAK. Unexpectedly, talin colocalization remained low even after activation of PKC. Treatment of cells with the PKC inhibitor calphostin C inhibited spreading and the colocalization of talin, alpha-actinin, tensin, and actin for both alpha v beta 3 and alpha v beta 5. We conclude that PKC regulates localization of cytoskeletal proteins and phosphorylation of FAK induced by alpha v beta 5. Our results also show that FAK can be localized independent of its phosphorylation and that cells can spread and induce localization of other focal adhesion proteins in the absence of detectable talin.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Proteína Quinase C
/
Proteínas Tirosina Quinases
/
Moléculas de Adesão Celular
/
Integrinas
Tipo de estudo:
Risk_factors_studies
Limite:
Animals
/
Humans
Idioma:
En
Revista:
J Cell Biol
Ano de publicação:
1996
Tipo de documento:
Article
País de afiliação:
Estados Unidos