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Imaging G-protein Coupled Receptor (GPCR)-mediated Signaling Events that Control Chemotaxis of Dictyostelium Discoideum
Published on: September 20, 2011
Odorant receptor-derived cAMP signals direct axonal targeting
Takeshi Imai1, Misao Suzuki, Hitoshi Sakano
1Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Tokyo 113-0032, Japan.
Science (New York, N.Y.)
|September 23, 2006
Summary
Cyclic adenosine monophosphate (cAMP) signals, not odorant receptors (ORs) themselves, guide olfactory sensory neuron (OSN) axons. These cAMP signals are essential for correct axonal projection to the olfactory bulb.
Area of Science:
- Neuroscience
- Molecular Biology
- Sensory Systems
Background:
- Odorant receptors (ORs) on olfactory sensory neurons (OSNs) are crucial for detecting smells.
- OSN axons must navigate precisely to target sites within the olfactory bulb for proper olfactory processing.
- The molecular mechanisms underlying this precise axonal targeting are not fully understood.
Purpose of the Study:
- To investigate the role of cyclic adenosine monophosphate (cAMP) signaling in OR-mediated axonal guidance.
- To determine whether OR molecules directly instruct axonal projection or if downstream signaling is responsible.
- To identify key components of the cAMP pathway involved in olfactory axonal targeting.
Main Methods:
- Genetic manipulation of ORs, G protein, cAMP-dependent protein kinase, and cAMP response element-binding protein in mammals.
- Analysis of axonal projection patterns of OSNs in the olfactory bulb using genetic models.
- Assessment of changes in target destination along the anterior-posterior axis of the olfactory bulb.
Main Results:
- Genetic alterations affecting the cAMP signaling pathway, including components like G protein and protein kinase, significantly altered OSN axonal projection sites.
- These manipulations resulted in shifts in the anterior-posterior targeting within the olfactory bulb.
- The study demonstrated a clear correlation between cAMP signaling levels and the precision of axonal targeting.
Conclusions:
- Cyclic adenosine monophosphate (cAMP) signaling is essential for the correct targeting of olfactory sensory neuron (OSN) axons in the olfactory bulb.
- The findings indicate that OR-derived cAMP signals, rather than the direct action of OR molecules, are the primary determinants of OSN axonal destination.
- This research elucidates a critical molecular mechanism governing neural circuit formation in the olfactory system.
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