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GPCR Binding and JNK3 Activation by Arrestin-3 Have Different Structural Requirements
Chen Zheng1, Liana D Weinstein1, Kevin K Nguyen1
1Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA.
Cells
|June 28, 2023
Summary
Arrestin-3 activates JNK3, but this function is independent of its binding to G protein-coupled receptors (GPCRs). Studies show arrestin-3’s GPCR binding and JNK3 activation have distinct structural needs.
Area of Science:
- Molecular and Cellular Biology
- Biochemistry
- Signal Transduction
Background:
- Arrestins bind activated, phosphorylated G protein-coupled receptors (GPCRs).
- Arrestin-3 is the only mammalian subtype that facilitates JNK3 activation.
- Lysine residues in arrestin subtypes are implicated in GPCR binding.
Purpose of the Study:
- To compare the roles of arrestin-3 conformational equilibrium and specific lysine residues in GPCR binding and JNK3 activation.
- To investigate the distinct structural requirements for GPCR binding versus JNK3 activation by arrestin-3.
Main Methods:
- Site-directed mutagenesis of arrestin-3, including charge neutralization and reversal of Lys-295.
- Assessment of GPCR binding affinity and JNK3 activation activity of arrestin-3 mutants.
- Analysis of subcellular distribution of arrestin-3 mutants.
Main Results:
- Mutants with enhanced GPCR binding showed reduced JNK3 activation, while a non-binding mutant was more active.
- Subcellular distribution did not correlate with GPCR recruitment or JNK3 activation.
- Lys-295 mutations differentially affected GPCR binding but had minimal impact on JNK3 activation.
Conclusions:
- GPCR binding and arrestin-3-mediated JNK3 activation possess distinct structural requirements.
- Facilitation of JNK3 activation by arrestin-3 may occur independently of GPCR binding.
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