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FRET-based detection of different conformations of MK2
A Neininger1, H Thielemann, M Gaestel
1Innovationskolleg Zellspezialisierung, Martin-Luther-Universität Halle Wittenberg, 06120 Halle, Germany.
EMBO Reports
|July 21, 2001
Summary
Stress-activated enzyme MAP kinase-activated protein kinase 2 (MK2) undergoes a conformational switch from closed to open upon activation. This switch, linked to phosphorylation, regulates its nuclear export and cellular localization.
Area of Science:
- Cellular Biology
- Molecular Biology
- Biochemistry
Background:
- MAP kinase-activated protein kinase 2 (MK2) is a downstream enzyme of the p38 MAPK pathway.
- MK2 plays a role in cellular stress responses.
Purpose of the Study:
- To investigate the conformational changes of MK2 during activation.
- To analyze the in vitro and in vivo behavior of MK2 using fluorescent protein fusions.
Main Methods:
- Utilized Förster resonance energy transfer (FRET) by fusing green fluorescent protein variants to MK2.
- Observed conformational changes in MK2 in vitro and in living cells.
- Investigated the role of nuclear export in MK2 localization.
Main Results:
- MK2 activation correlated with a decrease in FRET, indicating a transition from a closed to an open conformation.
- The closed conformation of MK2 was exclusively found in the nucleus.
- Upon stress, the open MK2 conformation appeared in the cytoplasm and accumulated in the nucleus when Crm1-dependent export was inhibited.
- Phosphorylation-dependent conformational switch coupled MK2 activation with nuclear export.
Conclusions:
- MK2 activation involves a significant conformational change from a closed to an open state.
- This conformational switch is critical for regulating MK2's localization between the nucleus and cytoplasm.
- The findings elucidate a phosphorylation-dependent mechanism coupling MK2 activation and nuclear export.