DUSP6/MKP-3 inactivates ERK1/2 but fails to bind and inactivate ERK5.
Extracellular signal-regulated kinase-1 and -2 (ERK1/2) are activated by dual threonine and tyrosine phosphorylation of a TEY motif. The highly related kinase ERK5 is also activated by phosphorylation at a TEY motif. Inactivation of ERK1/2 is achieved by distinct members of the dual-specificity protein phosphatase (DUSP) family, which are responsible for the specific, regulated de-phosphorylation of the TEY motif. These include both nuclear (DUSP5) and cytoplasmic (DUSP6) enzymes. DUSP6, a candidate tumour suppressor gene, is thought to be highly specific for inactivation of ERK1/2 but several reports have suggested that it may also inactivate ERK5. Here we have compared the ability of DUSP6 to regulate the ERK1/2 and ERK5 protein kinases. We find that DUSP6 binds to ERK1/2 in both yeast and human cells but fails to bind to ERK5. Recombinant ERK2 can induce catalytic activation of DUSP6 whereas ERK5 cannot. Ectopic expression of DUSP6 can de-phosphorylate a co-expressed ERK2 construct but does not de-phosphorylate ERK5. Finally, expression of DUSP6 blocks the MEK1-driven activation of GAL4-ELK1, an ERK1/2-regulated transcription factor, but fails to block the MEK5-driven activation of GAL4-MEF2D, an ERK5-regulated transcription factor. These results demonstrate that even upon over-expression DUSP6 fails to inactivate ERK5, confirming that it is indeed an ERK1/2-specific DUSP.
Arkell
Rebecca S
RS
Laboratory of Molecular Signalling, The Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, UK.
Dickinson
Robin J
RJ
Squires
Matthew
M
Hayat
Shaista
S
Keyse
Stephen M
SM
Cook
Simon J
SJ
D002460:Cell Line; D054642:Dual Specificity Phosphatase 6 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D026161:MADS Domain Proteins / Q000378:metabolism; D064326:MEF2 Transcription Factors; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D048054:Mitogen-Activated Protein Kinase 7 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D018006:Myogenic Regulatory Factors / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014162:Transfection; D020798:Two-Hybrid System Techniques; D050807:ets-Domain Protein Elk-1 / Q000378:metabolism
C494112:ELK1 protein, human; D026161:MADS Domain Proteins; D064326:MEF2 Transcription Factors; C578043:MEF2D protein, human; D018006:Myogenic Regulatory Factors; D011994:Recombinant Proteins; D050807:ets-Domain Protein Elk-1; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048054:Mitogen-Activated Protein Kinase 7; C517035:DUSP6 protein, human; D054642:Dual Specificity Phosphatase 6