Regulation of carbamoyl phosphate synthetase by MAP kinase.
Nature
; 403(6767): 328-32, 2000 Jan 20.
Article
em En
| MEDLINE
| ID: mdl-10659854
ABSTRACT
The de novo synthesis of pyrimidine nucleotides is required for mammalian cells to proliferate. The rate-limiting step in this pathway is catalysed by carbamoyl phosphate synthetase (CPS II), part of the multifunctional enzyme CAD. Here we describe the regulation of CAD by the mitogen-activated protein (MAP) kinase cascade. When phosphorylated by MAP kinase in vitro or activated by epidermal growth factor in vivo, CAD lost its feedback inhibition (which is dependent on uridine triphosphate) and became more sensitive to activation (which depends upon phosphoribosyl pyrophosphate). Both these allosteric regulatory changes favour biosynthesis of pyrimidines for growth. They were accompanied by increased epidermal growth factor-dependent phosphorylation of CAD in vivo and were prevented by inhibition of MAP kinase. Mutation of a consensus MAP kinase phosphorylation site abolished the changes in CAD allosteric regulation that were stimulated by growth factors. Finally, consistent with an effect of MAP kinase signalling on CPS II activity, epidermal growth factor increased cellular uridine triphosphate and this increase was reversed by inhibition of MAP kinase. Hence these studies may indicate a direct link between activation of the MAP kinase cascade and de novo biosynthesis of pyrimidine nucleotides.
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Base de dados:
MEDLINE
Assunto principal:
Aspartato Carbamoiltransferase
/
Carbamoil Fosfato Sintase (Glutamina-Hidrolizante)
/
Proteínas Quinases Ativadas por Mitógeno
/
Sistema de Sinalização das MAP Quinases
/
Di-Hidro-Orotase
/
Complexos Multienzimáticos
Idioma:
En
Ano de publicação:
2000
Tipo de documento:
Article