Related Experiment Video
Updated: Jul 25, 2026
11:35
Flash Photolysis of Caged Compounds in the Cilia of Olfactory Sensory Neurons
Published on: October 29, 2011
Phosducin, potential role in modulation of olfactory signaling
I Boekhoff1, K Touhara, S Danner
1University Stuttgart-Hohenheim, Institute of Zoophysiology, 70599 Stuttgart, Federal Republic of Germany.
The Journal of Biological Chemistry
|February 14, 1997
Summary
Phosducin regulates olfactory signal transduction by controlling Gbetagamma-subunit availability. Phosphorylation of phosducin acts as a switch, modulating receptor kinase GRK3 translocation and desensitization kinetics.
Area of Science:
- Molecular Biology
- Cell Signaling
- Neuroscience
Background:
- Phosducin binds Gbetagamma subunits, but its regulatory role in signaling cascades remains unclear.
- Olfactory signal transduction involves cyclic AMP (cAMP) response termination by protein kinase A (PKA) and G-protein coupled receptor kinase 3 (GRK3).
- GRK3 translocation to plasma membrane receptors is mediated by Gbetagamma subunits.
Purpose of the Study:
- To investigate the function of phosducin in olfactory signal transduction.
- To elucidate the mechanism by which phosducin regulates odorant-induced cAMP response termination and GRK3 activity.
Main Methods:
- Detection and characterization of phosducin in olfactory cilia using SDS-PAGE and Western blotting.
- Inhibition studies using recombinant phosducin and specific inhibitors in permeabilized olfactory cilia preparations.
- Analysis of GRK3 membrane translocation and cAMP response kinetics.
- Site-directed mutagenesis of phosducin to create non-phosphorylatable and phospho-mimetic mutants.
Main Results:
- A 33 kDa protein immunoreactive with phosducin antibodies was identified in olfactory cilia.
- Recombinant phosducin inhibited odorant-induced cAMP response termination and GRK3 membrane translocation.
- Phosphorylation of phosducin by PKA reduced its Gbetagamma affinity, promoting GRK3 translocation.
- Non-phosphorylatable phosducin mutant was a more potent inhibitor than wild-type, while phospho-mimetic mutant potentiated desensitization.
Conclusions:
- Phosducin acts as a phosphorylation-dependent switch in olfactory signal transduction.
- Phosducin regulates desensitization kinetics by controlling Gbetagamma-dependent GRK3 activity.
- Modulation of phosducin phosphorylation state impacts olfactory signal termination.
More Related Videos
10:16Perforated Patch-clamp Recording of Mouse Olfactory Sensory Neurons in Intact Neuroepithelium: Functional Analysis of Neurons Expressing an Identified Odorant Receptor
Published on: July 13, 2015
09:11Live-cell Measurement of Odorant Receptor Activation Using a Real-time cAMP Assay
Published on: October 2, 2017
Related Concept Videos
01:25Olfaction
The sense of smell is achieved through the activities of the olfactory system. It starts when an airborne odorant enters the nasal cavity and reaches olfactory epithelium (OE). The OE is protected by a thin layer of mucus, which also serves the purpose of dissolving more complex compounds into simpler chemical odorants. The size of the OE and the density of sensory neurons varies among species; in humans, the OE is only about 9-10 cm2.
The olfactory receptors are embedded in the cilia of the...
The olfactory receptors are embedded in the cilia of the...
01:11Channel Rhodopsins
Most organisms use photoreceptors to sense and respond to light. Examples of photoreceptors include bacteriorhodopsins and bacteriophytochromes in some bacteria, phytochromes in plants, and rhodopsins in the photoreceptor cells of the vertebral retina. The light-sensitive property of these receptors is because of the bound chromophores, such as bilin in the phytochromes and retinal in the rhodopsins.
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
01:21G-Protein Gated Ion Channels
GPCRs are primarily responsible for our sense of smell, taste, and vision. The binding of a sensory stimulus activates GPCR to stimulate effector proteins, many of which are ion channels in the sensory organs. GPCRs modulate the opening and closing of the target ion channels either directly by binding them, or by releasing second messengers that activate these channels. As ions move across the membrane, the membrane potential is altered, which induces an appropriate response.
Sensory organs,...
Sensory organs,...
01:03Olfactory Receptors: Location and Structure
The process of olfaction, also known as the sense of smell, is a sophisticated chemical response system. The specialized sensory neurons that facilitate this process, known as olfactory receptor neurons, are situated in an upper segment of the nasal cavity, known as the olfactory epithelium. Olfactory sensory neurons are bipolar, with their dendrites extending from the epithelium's apex into the mucus that lines the nasal cavity. Airborne molecules, when inhaled, traverse the olfactory...
01:20Physiology of Smell and Olfactory Pathway
Humans detect odors with the help of specialized cells located in the upper part of the nasal cavity, called olfactory receptor neurons (ORNs). ORNs possess hair-like structures called cilia, which are receptive to sensations from the inhaled air. When an odorant molecule binds to a specific receptor on the cell of the cilia, it leads to a series of events that ultimately cause the ORN to send electrical signals to the olfactory bulb in the brain through the olfactory nerves.
The olfactory...
The olfactory...