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Solution structure of ERK2 binding domain of MAPK phosphatase MKP-3: structural insights into MKP-3 activation by
A Farooq1, G Chaturvedi, S Mujtaba
1Structural Biology Program, Department of Physiology and Biophysics, Mount Sinai School of Medicine, New York University, New York, NY 10029, USA.
Abstract:
MAP kinases (MAPKs), which control mitogenic signal transduction in all eukaryotic organisms, are inactivated by dual specificity MAPK phosphatases (MKPs). MKP-3, a prototypical MKP, achieves substrate specificity through its N-terminal domain binding to the MAPK ERK2, resulting in the activation of its C-terminal phosphatase domain. The solution structure and biochemical analysis of the ERK2 binding (EB) domain of MKP-3 show that regions that are essential for ERK2 binding partly overlap with its sites that interact with the C-terminal catalytic domain, and that these interactions are functionally coupled to the active site residues of MKP-3. Our findings suggest a novel mechanism by which the EB domain binding to ERK2 is transduced to cause a conformational change of the C-terminal catalytic domain, resulting in the enzymatic activation of MKP-3.
Insights
Dual specificity MAPK phosphatases (MKPs) inactivate MAP kinases. MKP-3
Area of Science:
- Molecular Biology
- Biochemistry
- Cell Signaling
Background:
- Mitogenic signal transduction is controlled by MAP kinases (MAPKs) in eukaryotes.
- Dual specificity MAPK phosphatases (MKPs) are key regulators that inactivate MAPKs.
- MKP-3, a specific MKP, utilizes its N-terminal domain to bind MAPK ERK2, activating its C-terminal phosphatase domain.
Purpose of the Study:
- To elucidate the structural and biochemical basis of MKP-3's substrate specificity and activation mechanism.
- To investigate the interaction between the ERK2 binding (EB) domain of MKP-3 and its C-terminal catalytic domain.
- To understand how ERK2 binding leads to enzymatic activation of MKP-3.
Main Methods:
- Solution structure determination of the ERK2 binding (EB) domain of MKP-3.
- Biochemical analysis of MKP-3 interactions.
- Functional assays to assess enzymatic activity.
Main Results:
- The EB domain of MKP-3 essential for ERK2 binding partially overlaps with sites interacting with the C-terminal catalytic domain.
- These interactions are functionally coupled to the active site residues of MKP-3.
- A novel mechanism for ERK2-mediated activation of MKP-3 is proposed.
Conclusions:
- The EB domain's interaction with ERK2 induces conformational changes in the C-terminal catalytic domain.
- This conformational change leads to the enzymatic activation of MKP-3.
- Findings reveal a new regulatory mechanism for MKP-3 activity in signal transduction pathways.