Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Channel Rhodopsins

Channel 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,...

Activation and Inactivation of G Proteins

Activation and Inactivation of G Proteins

Heterotrimeric G proteins are guanine nucleotide-binding proteins. As the name suggests, heterotrimeric G proteins are composed of three subunits: alpha, beta, and gamma. They remain GDP-bound or GTP-bound inside the cells and switch between inactive/active states. The Gα subunit possesses the nucleotide-binding pocket that binds guanine nucleotides and switches between GDP or GTP-bound states. In contrast, the Gꞵ and Gγ subunits are always bound together with high affinity and are together...

G-Protein Gated Ion Channels

G-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,...

Photoreceptors and Visual Pathways

Photoreceptors and Visual Pathways

At the molecular level, visual signals trigger transformations in photopigment molecules, resulting in changes in the photoreceptor cell's membrane potential. The photon's energy level is denoted by its wavelength, with each specific wavelength of visible light associated with a distinct color. The spectral range of visible light, classified as electromagnetic radiation, spans from 380 to 720 nm. Electromagnetic radiation wavelengths exceeding 720 nm fall under the infrared category, whereas...

Repressible Operon: trp Operon

Repressible Operon: trp Operon

The trp operon in Escherichia coli exemplifies a repressible operon. It regulates the synthesis of tryptophan through repressor-mediated transcriptional control and attenuation. This dual regulatory mechanism ensures tryptophan biosynthesis occurs only when needed, conserving cellular resources.Structure of the trp OperonThe trp operon consists of five structural genes (trpE, trpD, trpC, trpB, and trpA) that encode enzymes for tryptophan biosynthesis. These genes are transcribed as a single...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Family History and Solar Insolation in Bipolar I Disorder.

Acta psychiatrica Scandinavica·2026

Same author

Tuning biological processes <i>via</i> co-solutes: from single proteins to protein condensates - the case of α-elastin condensation.

Chemical science·2025

Same author

Sociability increases survival of adult female giraffes.

Proceedings. Biological sciences·2021

Same author

TREM-1 and TREM-2 Expression on CD14<sup>+</sup> Cells in Bronchoalveolar Lavage Fluid in Pulmonary Sarcoidosis and Hypersensitivity Pneumonitis in the Context of T Cell Immune Response.

Mediators of inflammation·2020

Same author

X-ray fluorescence analysis of metal distributions in cryogenic biological samples using large-acceptance-angle SDD detection and continuous scanning at the Hard X-ray Micro/Nano-Probe beamline P06 at PETRA III.

Journal of synchrotron radiation·2019

Same author

Characterization of the in situ pellicle ultrastructure formed under the influence of bovine milk and milk protein isolates.

Archives of oral biology·2019

Search research articles

Related Experiment Video

Updated: Jul 22, 2026

A Rhodopsin Transport Assay by High-Content Imaging Analysis

A Rhodopsin Transport Assay by High-Content Imaging Analysis

Published on: January 16, 2019

Rhodopsin mutants that bind but fail to activate transducin.

R R Franke¹, B König, T P Sakmar

¹Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.

Science (New York, N.Y.)

|October 5, 1990

Summary

Mutant rhodopsins with altered cytoplasmic loops were studied. Some bound the G protein transduction (Gt) but could not activate it, indicating these loops are crucial for Gt activation.

More Related Videos

Electrophysiological Methods for Measuring Photopigment Levels in Drosophila Photoreceptors

Electrophysiological Methods for Measuring Photopigment Levels in Drosophila Photoreceptors

Published on: June 2, 2022

Methodology for Studying Interactions of Vitamin A Membrane Receptors and Opsin Protein with their Ligands in Generating the Retinylidene Protein

Methodology for Studying Interactions of Vitamin A Membrane Receptors and Opsin Protein with their Ligands in Generating the Retinylidene Protein

Published on: October 4, 2024

Related Experiment Videos

Last Updated: Jul 22, 2026

A Rhodopsin Transport Assay by High-Content Imaging Analysis

A Rhodopsin Transport Assay by High-Content Imaging Analysis

Published on: January 16, 2019

Electrophysiological Methods for Measuring Photopigment Levels in Drosophila Photoreceptors

Electrophysiological Methods for Measuring Photopigment Levels in Drosophila Photoreceptors

Published on: June 2, 2022

Methodology for Studying Interactions of Vitamin A Membrane Receptors and Opsin Protein with their Ligands in Generating the Retinylidene Protein

Methodology for Studying Interactions of Vitamin A Membrane Receptors and Opsin Protein with their Ligands in Generating the Retinylidene Protein

Published on: October 4, 2024

Area of Science:

Molecular Biology
Biochemistry
Structural Biology

Background:

Rhodopsin, a G protein-coupled receptor, plays a vital role in visual signal transduction.
Understanding the interaction between rhodopsin and its cognate G protein, transduction (Gt), is key to deciphering cellular signaling pathways.

Purpose of the Study:

To investigate the functional roles of rhodopsin's cytoplasmic loops in Gt binding and activation.
To elucidate the specific molecular interactions governing Gt signal initiation.

Main Methods:

Flash photolysis was employed to directly monitor Gt binding and dissociation kinetics.
Site-directed mutagenesis was used to create rhodopsin mutants (CD1, CD2, EF1) with alterations in cytoplasmic loops.

Main Results:

Three mutant opsins bound 11-cis-retinal and exhibited native absorption spectra.
Mutant CD1 failed to bind Gt, while mutants CD2 and EF1 bound Gt but did not release it upon GTP addition.
Mutants CD2 and EF1 were unable to stimulate Gt's guanosine triphosphatase activity.

Conclusions:

The second and third cytoplasmic loops of rhodopsin are essential for the activation of bound Gt.
Specific structural elements within these loops are critical for initiating the Gt signaling cascade.