These authors contributed equally to this work.
Molecular mechanism of ERK dephosphorylation by striatal-enriched protein tyrosine phosphatase
Article first published online: 31 OCT 2013
© 2013 International Society for Neurochemistry
Journal of Neurochemistry
Volume 128, Issue 2, pages 315–329, January 2014
How to Cite
J. Neurochem. (2014) 128, 315–329.
- Issue published online: 6 JAN 2014
- Article first published online: 31 OCT 2013
- Accepted manuscript online: 30 SEP 2013 09:18AM EST
- Manuscript Accepted: 23 SEP 2013
- Manuscript Revised: 20 SEP 2013
- Manuscript Received: 27 MAY 2013
- National Key Basic Research Program of China. Grant Numbers: 2013CB967700, 2012CB910402
- National Natural Science Foundation of China. Grant Numbers: 81171062, 31100580, 31271505, 31000362, 31270857, 81100836
- Foundation of Program for New Century Excellent Talents in University, China. Grant Number: NCET-09-0531
- Foundation for Excellent Young and Middle-Aged Scientists of Shandong Province, China. Grant Number: BS2011SW020
- Independence Innovation Foundation of Shandong University. Grant Number: 2012TS114
- National Institutes of Health. Grant Numbers: HL095556, HL108922
- ERK ;
- neurological disorders;
- striatal enriched tyrosine phosphatases;
- synaptic plasticity
Striatal-enriched tyrosine phosphatase (STEP) is an important regulator of neuronal synaptic plasticity, and its abnormal level or activity contributes to cognitive disorders. One crucial downstream effector and direct substrate of STEP is extracellular signal-regulated protein kinase (ERK), which has important functions in spine stabilisation and action potential transmission. The inhibition of STEP activity toward phospho-ERK has the potential to treat neuronal diseases, but the detailed mechanism underlying the dephosphorylation of phospho-ERK by STEP is not known. Therefore, we examined STEP activity toward para-nitrophenyl phosphate, phospho-tyrosine-containing peptides, and the full-length phospho-ERK protein using STEP mutants with different structural features. STEP was found to be a highly efficient ERK tyrosine phosphatase that required both its N-terminal regulatory region and key residues in its active site. Specifically, both kinase interaction motif (KIM) and kinase-specific sequence of STEP were required for ERK interaction. In addition to the N-terminal kinase-specific sequence region, S245, hydrophobic residues L249/L251, and basic residues R242/R243 located in the KIM region were important in controlling STEP activity toward phospho-ERK. Further kinetic experiments revealed subtle structural differences between STEP and HePTP that affected the interactions of their KIMs with ERK. Moreover, STEP recognised specific positions of a phospho-ERK peptide sequence through its active site, and the contact of STEP F311 with phospho-ERK V205 and T207 were crucial interactions. Taken together, our results not only provide the information for interactions between ERK and STEP, but will also help in the development of specific strategies to target STEP-ERK recognition, which could serve as a potential therapy for neurological disorders.
Regulation of phospho-ERK by STEP underlies important neuronal activities. A detailed enzymologic characterisation and cellular studies of STEP revealed that specific residues in KIM and active site mediated ERK recognition. Structural differences between the KIM-ERK interfaces and the active site among different ERK phosphatases could be targeted to develop specific STEP inhibitor, which has therapeutic potential for neurological disorders. PKA, protein kinase A & NGF, nerve growth factor.