G Protein Signaling
G Protein Signaling - Related Videos
12:24
Mimicking the Function of Signaling Proteins: Toward Artificial Signal Transduction Therapy
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2016
We present guidelines for developing synthetic 'chemical transducers' that can induce communication between naturally unrelated proteins. In addition, detailed protocols are presented for synthesizing and testing a specific 'transducer' that enables a growth factor to activate a detoxifying enzyme and consequently, to regulate the cleavage of an anticancer prodrug.
06:45
Dissecting Multi-protein Signaling Complexes by Bimolecular Complementation Affinity Purification (BiCAP)
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Cited by 4 •
2018
This manuscript describes the protocol for Bimolecular Complementation Affinity Purification (BiCAP). This novel method facilitates the specific isolation and downstream proteomic characterization of any two interacting proteins, while excluding un-complexed individual proteins as well as complexes formed with competing binding partners.
09:40
Imaging G-protein Coupled Receptor (GPCR)-mediated Signaling Events that Control Chemotaxis of Dictyostelium Discoideum
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Cited by 2 •
2011
Here, we describe detailed live cell imaging methods for investigating chemotaxis. We present fluorescence microscopic methods to monitor spatiotemporal dynamics of signaling events in migrating cells. Measurement of signaling events permits us to further understand how a GPCR-signaling network achieves gradient sensing of chemoattractants and controls directional migration of eukaryotic cells.
08:24
Imaging G Protein-coupled Receptor-mediated Chemotaxis and its Signaling Events in Neutrophil-like HL60 Cells
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Cited by 7 •
2016
Visual chemotaxis assays are essential for a better understanding of how eukaryotic cells control chemoattractant-mediated directional cell migration. Here, we describe detailed methods for: 1) real-time, high-resolution monitoring of multiple chemotaxis assays, and 2) simultaneously visualizing the chemoattractant gradient and the spatiotemporal dynamics of signaling events in neutrophil-like HL60 cells.
06:55
Polarized Translocation of Fluorescent Proteins in Xenopus Ectoderm in Response to Wnt Signaling
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Cited by 2 •
2011
Xenopus embryonic ectoderm has become an attractive model for studies of cell polarity. An assay is described, in which subcellular distribution of fluorescent proteins is assessed in ectoderm cells. This protocol will help address questions related to spatial control of signaling.
FAQs
The key molecular switch is the exchange of GDP for GTP on the heterotrimeric G protein. Ligand-bound receptor activity promotes this exchange, changing the signaling state of the G protein. That switch matters because it links recognition of an extracellular cue to downstream intracellular regulation, allowing the same general communication architecture to respond to different signals.
After activation, the G protein subunits influence distinct intracellular effectors, including adenylyl cyclase, phospholipase C, and ion channels. These effectors generate or regulate second-messenger signals, which carry the receptor's information through the cell. The particular effector engaged helps determine the response, connecting receptor stimulation with outcomes such as metabolism, movement, secretion, or gene expression.
Signal termination depends on returning the G protein to its GDP-associated state through GTP hydrolysis. Receptor regulatory control also limits continued signaling. Together, these processes prevent an activating cue from remaining indefinitely active and make responses reversible. Their importance is biological as well as mechanistic, because controlled duration helps cells adjust signaling to changing extracellular conditions.
The pathway can produce different outcomes because receptor activation is connected to multiple types of effectors and second-messenger signals. Changes in those intracellular signals can influence metabolism, movement, secretion, or gene expression, even though the initial event is an extracellular cue. This makes the system useful for studying how cells translate communication into coordinated biological activity.
A practical analysis follows the pathway in order: identify the extracellular ligand and receptor, examine GDP-to-GTP exchange on the heterotrimeric G protein, determine which subunits affect adenylyl cyclase, phospholipase C, or ion channels, and then track resulting second-messenger signals and response termination. This sequence separates signal initiation, transmission, cellular outcome, and shutoff.
Its research value comes from connecting receptor activity to intracellular signaling and physiological outcomes. Investigators can use that connection to clarify normal biology and examine conditions involving receptor or signaling defects. The same framework also supports drug research by focusing attention on receptor regulation, G protein activation, downstream effectors, second messengers, and signal termination.