Interleukin-1 stimulated activation of the COT catalytic subunit through the phosphorylation of Thr290 and Ser62.
The protein kinase COT/Tpl2 is activated by interleukin-1 (IL-1), TNFalpha and lipopolysaccharide, and its activation by these agonists involves the IkappaB kinase beta (IKKbeta) catalysed phosphorylation of the p105 regulatory subunit. Here, we show that COT activation also requires catalytic subunit phosphorylation, since IL-1beta induced a 5-10-fold activation of a COT mutant unable to bind p105. Activation was paralleled by the phosphorylation of Thr290 and Ser62 and unaffected by the IKKbeta inhibitor PS1145 at concentrations which prevented the degradation of IkappaBalpha. Mutagenesis experiments indicated that COT activation is initiated by Thr290 phosphorylation catalysed by an IL-1-stimulated protein kinase distinct from IKKbeta, while Ser62 phosphorylation is an autophosphorylation event required for maximal activation.
Stafford
Margaret J
MJ
MRC Protein Phosphorylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
Morrice
Nick A
NA
Peggie
Mark W
MW
Cohen
Philip
P
D000595:Amino Acid Sequence; D020134:Catalytic Domain / Q000187:drug effects*; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D020930:MAP Kinase Kinase Kinases / Q000737:chemistry / Q000378:metabolism*; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010768:Phosphoserine / Q000378:metabolism*; D010769:Phosphothreonine / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000737:chemistry / Q000378:metabolism*
D007375:Interleukin-1; D011518:Proto-Oncogene Proteins; D010769:Phosphothreonine; D010768:Phosphoserine; D020930:MAP Kinase Kinase Kinases; C069937:MAP3K8 protein, human