Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Positive Regulator Molecules02:39

Positive Regulator Molecules

5.4K
Mitotic cell division results in daughter cells that exactly resemble the parent cell. However, errors in the DNA replication or distribution of genetic material may lead to genetic mutations that may be passed down to every new cell formed from the resulting abnormal cell. Propagation of such mutant cells is restricted through checkpoint mechanisms present at different stages of the cell cycle. These checkpoints involve regulator molecules that either promote or demote cell cycle events.
5.4K
Circadian Rhythms and Gene Regulation02:19

Circadian Rhythms and Gene Regulation

4.0K
The biological clock is involved in many aspects of regulating complex physiology in all animals. It was in 1935 when German zoologists, Hans Kalmus and Erwin Bünning, discovered the existence of circadian rhythm in Drosophila melanogaster. However, the internal molecular mechanisms behind the circadian clock remained a mystery until 1984, when Jeffrey C. Hall, Michael Rosbash, and Michael W. Young discovered the expression of the Per gene oscillating over a 24-hour cycle. In subsequent...
4.0K
Structural Protein Function01:56

Structural Protein Function

27.6K
Structural proteins are a category of proteins responsible for functions ranging from cell shape and movement to providing support to major structures such as bones, cartilage, hair, and muscles. This group includes proteins such as collagen, actin, myosin, and keratin.
Collagen, the most abundant protein in mammals, is found throughout the body. In connective tissue, such as skin, ligaments, and tendons, it provides tensile strength and elasticity.  In bones and teeth, it mineralizes to...
27.6K
Calmodulin-dependent Signaling01:16

Calmodulin-dependent Signaling

5.1K
Calmodulin (CaM) is a calcium-binding protein in eukaryotes that controls various calcium-regulated cellular processes. It has four calcium-binding sites that bind calcium to form the calcium-calmodulin ( Ca2+-CaM) complex. GPCR stimulation increases the calcium levels in the cells that bind to CaM and induces a conformational change.
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
5.1K
Co-activators and Co-repressors02:04

Co-activators and Co-repressors

7.3K
Gene transcription is regulated by the synergistic action of several proteins that form a complex at a gene regulatory site. This is observed in eukaryotes, where the regulation of gene expression is a complex process. Regulatory proteins in eukaryotes can broadly be classified into two types – regulators that bind directly to specific DNA sequences and co-regulators that associate with regulatory proteins but cannot directly bind to the DNA. These co-regulators are further divided into...
7.3K
Assembly of Signaling Complexes01:30

Assembly of Signaling Complexes

5.7K
Multiprotein signaling complexes are formed in a dynamic process involving protein-protein interactions at the cytoplasmic domain of transmembrane receptors or enzymatic and non-enzymatic proteins associated with the receptor. These complexes ensure the activation and propagation of intracellular signals that regulate cell functions.
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...
5.7K

You might also read

Related Articles

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

Sort by
Same author

A planar dimer of bovine ATP synthase.

Cell death and differentiation·2026
Same author

Gaining insights into MmpL3: combining structural and computational approaches to unlock transport and inhibitor-binding mechanisms.

Acta crystallographica. Section D, Structural biology·2026
Same author

The Norway-Japan bilateral symposium: Dialogue in biophysics beginning in Nara.

Biophysics and physicobiology·2026
Same author

Effects of the signaling molecule cyclic-di-GMP on cyanobacterial circadian rhythm in <i>Synechococcus elongatus</i> PCC 7942.

Journal of bacteriology·2026
Same author

Cryo-EM structures of a MexB-MexY chimeric efflux pump reveal that large open clefts are intrinsic to the MexY porter domain.

Acta crystallographica. Section F, Structural biology communications·2026
Same author

Structure of chloramphenicol-bound MexB reveals residues in the distal binding pocket that are critical for substrate recognition.

Journal of biochemistry·2026

Related Experiment Video

Updated: Jun 25, 2025

Rapid Analysis of Circadian Phenotypes in Arabidopsis Protoplasts Transfected with a Luminescent Clock Reporter
07:42

Rapid Analysis of Circadian Phenotypes in Arabidopsis Protoplasts Transfected with a Luminescent Clock Reporter

Published on: September 17, 2016

12.8K

Structure-function relationship of KaiC around dawn.

Yoshihiko Furuike1,2, Eiki Yamashita3, Shuji Akiyama1,2

  • 1Research Center of Integrative Molecular Systems (CIMoS), Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, Aichi 444-8585, Japan.

Biophysics and Physicobiology
|May 28, 2024
PubMed
Summary
This summary is machine-generated.

Cyanobacterial circadian clock enzyme KaiC

Keywords:
ATPaseCircadian clockCyanobacteriaPhosphorylation

More Related Videos

Monitoring Cell-autonomous Circadian Clock Rhythms of Gene Expression Using Luciferase Bioluminescence Reporters
10:38

Monitoring Cell-autonomous Circadian Clock Rhythms of Gene Expression Using Luciferase Bioluminescence Reporters

Published on: September 27, 2012

22.4K
Mapping the Structure-Function Relationships of Disordered Oncogenic Transcription Factors Using Transcriptomic Analysis
09:58

Mapping the Structure-Function Relationships of Disordered Oncogenic Transcription Factors Using Transcriptomic Analysis

Published on: June 27, 2020

2.8K

Related Experiment Videos

Last Updated: Jun 25, 2025

Rapid Analysis of Circadian Phenotypes in Arabidopsis Protoplasts Transfected with a Luminescent Clock Reporter
07:42

Rapid Analysis of Circadian Phenotypes in Arabidopsis Protoplasts Transfected with a Luminescent Clock Reporter

Published on: September 17, 2016

12.8K
Monitoring Cell-autonomous Circadian Clock Rhythms of Gene Expression Using Luciferase Bioluminescence Reporters
10:38

Monitoring Cell-autonomous Circadian Clock Rhythms of Gene Expression Using Luciferase Bioluminescence Reporters

Published on: September 27, 2012

22.4K
Mapping the Structure-Function Relationships of Disordered Oncogenic Transcription Factors Using Transcriptomic Analysis
09:58

Mapping the Structure-Function Relationships of Disordered Oncogenic Transcription Factors Using Transcriptomic Analysis

Published on: June 27, 2020

2.8K

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Chronobiology

Background:

  • KaiC is central to the cyanobacterial circadian clock, possessing ATPase and autokinase/autophosphatase activities.
  • Understanding the interplay between KaiC's N-terminal (ATPase) and C-terminal (kinase/phosphatase) domains is crucial for circadian rhythmicity.
  • The dawn phase, involving KaiC dephosphorylation, remains poorly understood structurally and functionally.

Purpose of the Study:

  • To investigate the cooperative relationship between KaiC's N-terminal and C-terminal domains during the night-to-morning transition.
  • To design a double mutation (S431A/T432A) to stabilize KaiC in a dephosphorylated state for mechanistic studies.

Main Methods:

  • Site-directed mutagenesis to create a double mutant (S431A/T432A).
  • Biochemical assays to assess ATPase and autophosphatase activities.
  • Structural analysis using existing crystal structures of KaiC.

Main Results:

  • The N-terminal and C-terminal domains of KaiC cooperate via salt bridges at the dawn phase.
  • This cooperation non-locally co-activates ATPase de-inhibition and S431 dephosphorylation.
  • KaiC domain states and their coupling are dynamic and influenced by KaiA interactions and hexameric structure.

Conclusions:

  • The study reveals a novel inter-domain cooperative mechanism in KaiC essential for circadian timing.
  • The findings provide insights into the dynamic regulation of KaiC's biochemical activities throughout the circadian cycle.
  • The designed double mutant serves as a valuable tool for future research on KaiC function.