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Constitutively active G protein-coupled receptor mutants block dictyostelium development
Minghang Zhang1, Mousumi Goswami, Dale Hereld
1Department of Microbiology and Molecular Genetics, The University of Texas Medical School at Houston, Houston, TX 77030, USA.
Molecular Biology of the Cell
|December 3, 2004
Summary
Dominant-negative mutants of the cAMP receptor cAR1 (a G protein-coupled receptor) were identified in Dictyostelium. These mutants constitutively activate adaptation pathways, blocking multicellular development.
Area of Science:
- Cellular biology
- Developmental biology
- Biochemistry
Background:
- cAR1, a G protein-coupled receptor (GPCR), is crucial for Dictyostelium multicellular development.
- cAR1 pathway activation is transient due to adaptation mechanisms that are not fully understood.
Purpose of the Study:
- To investigate the adaptation mechanisms of cAR1 signaling.
- To identify mutations affecting cAR1 function and development.
Main Methods:
- Genetic screen for dominant-negative cAR1 mutants (DN1-4).
- Assessed in vitro adenylyl cyclase activation and cAMP binding affinities.
- Analyzed receptor phosphorylation and identified activating mutations (L100H, I104N).
Main Results:
- DN mutants constitutively activate adaptation pathways, inhibiting cAR1-mediated responses.
- Mutant receptors exhibit high cAMP affinities and constitutive phosphorylation.
- Activating mutations L100H and I104N are located near the conserved (E/D)RY motif.
Conclusions:
- Dominant-negative cAR1 mutants are constitutively activated.
- Constitutive activation leads to pathway adaptation, blocking multicellular development.
- Findings provide insights into GPCR regulation and adaptation mechanisms.