PKD2 and RSK1 Regulate Integrin ß4 Phosphorylation at Threonine 1736.
PLoS One
; 10(11): e0143357, 2015.
Article
en En
| MEDLINE
| ID: mdl-26580203
The integrin α6ß4, a major component of hemidesmosomes (HDs), stabilizes keratinocyte cell adhesion to the epidermal basement membrane through binding to the cytoskeletal linker protein plectin and association with keratin filaments. Disruption of the α6ß4-plectin interaction through phosphorylation of the ß4 subunit results in a reduction in adhesive strength of keratinocytes to laminin-332 and the dissolution of HDs. Previously, we have demonstrated that phosphorylation of T1736 in the C-terminal end of the ß4 cytoplasmic domain disrupts the interaction of ß4 with the plakin domain of plectin. Furthermore, we showed that ß4-T1736 can be phosphorylated by PKD1 in vitro, and although both PMA and EGF induced T1736 phosphorylation, only PMA was able to activate PKD1. Here, we show that depletion of [Ca2+]i augments PMA- and EGF-induced phosphorylation of ß4-T1736 and that this is caused by inhibition of the calcium-sensitive protein phosphatase calcineurin and augmentation of ERK1/2 activation. We also show that in keratinocytes the PMA-stimulated phosphorylation of ß4-T1736 primarily is mediated by PKD2 activation downstream of PKCδ. On the other hand, both the EGF-stimulated phosphorylation of T1736 and the EGF-induced dissolution of HDs are dependent on a functional MAPK signaling pathway, and treatment with the RSK inhibitor BI-D1870 prevented EGF-stimulated phosphorylation of ß4-T1736. Moreover, phosphorylation of ß4-T1736 is enhanced by overexpression of wild-type RSK1, while it is reduced by the expression of kinase-inactive RSK1 or by siRNA-mediated depletion of RSK1. In summary, our data indicate that different stimuli can lead to the phosphorylation of ß4-T1736 by either PKD2 or RSK1.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Treonina
/
Queratinocitos
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Hemidesmosomas
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Proteínas Quinasas S6 Ribosómicas 90-kDa
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Integrina alfa6beta4
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Canales Catiónicos TRPP
Idioma:
En
Revista:
PLoS One
Asunto de la revista:
CIENCIA
/
MEDICINA
Año:
2015
Tipo del documento:
Article
País de afiliación:
Países Bajos
Pais de publicación:
Estados Unidos