Regulation of carbamoyl phosphate synthetase by MAP kinase

• Published in: Nature (London) 2000-01, Vol.403 (6767), p.328-332
• Main Authors: Graves, Lee M, Guy, Hedeel I, Kozlowski, Piotr, Huang, Min, Lazarowski, Eduardo, Pope, R. Marshall, Collins, Matthew A, Dahlstrand, Erik N, Earp, H. Shelton, Evans, David R
• Format: Article
• Language: English
• Subjects: Allosteric Regulation; Amino Acid Sequence; Animals; Aspartate Carbamoyltransferase - antagonists & inhibitors; Aspartate Carbamoyltransferase - chemistry; Aspartate Carbamoyltransferase - genetics; Aspartate Carbamoyltransferase - metabolism; Biological and medical sciences; Biosynthesis; Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing) - antagonists & inhibitors; Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing) - chemistry; Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing) - genetics; Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing) - metabolism; Cell Line; Cell physiology; Cells; Cricetinae; Dihydroorotase - antagonists & inhibitors; Dihydroorotase - chemistry; Dihydroorotase - genetics; Dihydroorotase - metabolism; Enzyme Activation; Enzyme Inhibitors - pharmacology; Enzymes; Flavonoids - pharmacology; Fundamental and applied biological sciences. Psychology; Growth factors; Humanities and Social Sciences; letter; MAP Kinase Signaling System; Mesocricetus; Mitogen-Activated Protein Kinases - antagonists & inhibitors; Mitogen-Activated Protein Kinases - metabolism; Molecular and cellular biology; Molecular biology; Molecular Sequence Data; multidisciplinary; Multienzyme Complexes - antagonists & inhibitors; Multienzyme Complexes - chemistry; Multienzyme Complexes - genetics; Multienzyme Complexes - metabolism; Mutagenesis, Site-Directed; Mutation; Phosphoribosyl Pyrophosphate - metabolism; Phosphorylation; Pyrimidine Nucleotides - biosynthesis; Rats; Science; Science (multidisciplinary); Signal transduction; Uridine Triphosphate - metabolism
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/35002111

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.