14-3-3 is phosphorylated by casein kinase I on residue 233. Phosphorylation at this site in vivo regulates Raf/14-3-3 interaction.
J Biol Chem
; 272(46): 28882-8, 1997 Nov 14.
Article
em En
| MEDLINE
| ID: mdl-9360956
ABSTRACT
14-3-3 proteins mediate interactions between proteins involved in signal transduction and cell cycle regulation. Phosphorylation of target proteins as well as 14-3-3 are important for protein-protein interactions. Here, we describe the purification of a protein kinase from porcine brain that phosphorylates 14-3-3 zeta on Thr-233. This protein kinase has been identified as casein kinase Ialpha (CKIalpha) by peptide mapping analysis and sequencing. Among mammalian 14-3-3, only 14-3-3 tau possesses a phosphorylatable residue at the same position (Ser-233), and we show that this residue is also phosphorylated by CKI. In addition, we show that 14-3-3 zeta is exclusively phosphorylated on Thr-233 in human embryonic kidney 293 cells. The residue 233 is located within a region shown to be important for the association of 14-3-3 to target proteins. We showed previously that, in 293 cells, only the unphosphorylated form of 14-3-3 zeta associates with the regulatory domain of c-Raf. We have now shown that in vivo phosphorylation of 14-3-3 zeta at the CKIalpha site (Thr-233) negatively regulates its binding to c-Raf, and may be important in Raf-mediated signal transduction.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas Quinases
/
Tirosina 3-Mono-Oxigenase
/
Proteínas
/
Proteínas Proto-Oncogênicas c-raf
Limite:
Animals
/
Humans
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
1997
Tipo de documento:
Article
País de afiliação:
Reino Unido