Name: cell cycle regulators that control division
Uploaded: 2023-06-23T15:38:45.000Z
Duration: 1 min 27 s
Channel: JoVE

K12 Standards

Next Generation Science Standards

High School

Life Science

from-molecules-to-organisms-structures-and-processes

From Molecules to Organisms: Structures and Processes

HS-LS1-4

molecular-factors-affecting-cell-division

Molecular Factors Affecting Cell Division

La division cellulaire, ou phase mitotique du cycle cellulaire, est contrôlée par des stimuli chimiques externes, tels que les facteurs de croissance et les hormones, et des facteurs internes, tels que les régulateurs du cycle cellulaire.
Le cycle cellulaire est régulé par une combinaison de protéines appelées cyclines et kinases dépendantes des cyclines ou Cdk. Les concentrations de différentes cyclines fluctuent avec les différentes phases du cycle cellulaire.
Lorsqu’une cellule approche de la fin de la phase G2, le niveau de cycline B augmente. À des concentrations élevées, la cycline B forme un complexe avec Cdk1 appelé facteur de promotion de la phase M ou MPF.
L’activité MPF est régulée par des événements de phosphorylation et de déphosphorylation qui déterminent si la cellule subit une division ou non.
Jusqu’à la fin de G2, la kinase Wee1 phosphoryle les résidus de tyrosine sur le MPF et le maintient inactif. Cela empêche l’entrée dans le cycle cellulaire et arrête la cellule à la phase G2/M.
Une fois que Cdc25 déphosphoryle le MPF, une kinase activatrice de Cdk phosphoryle une thréonine conservée sur le MPF et l’active.
Maintenant, les cellules subissent une mitose et produisent deux cellules filles.

facteurs moléculaires affectant la division cellulaire

Plusieurs facteurs externes et internes influencent l'initiation et l'inhibition de la division cellulaire. Par exemple, la mort des cellules environnantes ou la libération de l'hormone de croissance humaine (hGH) favorise la division cellulaire. En revanche, le manque de hGH ou l'encombrement des cellules peuvent inhiber la division cellulaire. Plusieurs protéines agissent en tant que régulateurs internes pour garantir que chaque étape du cycle cellulaire est complétée avec fidélité avant de passer à la suivante. Les molécules régulatrices peuvent agir directement ou influencer l'activité ou la production d'autres protéines régulatrices. Ces molécules régulatrices favorisent soit la progression de la cellule vers la phase suivante (régulation positive) soit l'arrêt du cycle (régulation négative). Les molécules régulatrices positives comprennent les cyclines et les kinases dépendantes des cyclines (Cdks) qui sont essentielles à la progression du cycle cellulaire. Alors que le niveau de Cdks reste constant, les niveaux de quatre cyclines (cyclines D, E, A et B) fluctuent au cours des différentes phases du cycle cellulaire. Lorsqu'elles se lient fermement aux Cdks, les cyclines sont phosphorylées pour être activées. Les niveaux de cycline D augmentent dans la phase G1, restent élevés tout au long du cycle, puis diminuent dans la phase M. Le niveau de cycline E atteint son maximum au carrefour de la phase G1-S, tandis que la cycline A est élevée pendant les phases S et G2. À l'approche de la phase M, le niveau de cycline B augmente et favorise la division cellulaire. Les molécules régulatrices négatives comprennent la protéine rétinoblastome (Rb), p53 et p21, qui arrêtent le cycle cellulaire. Par exemple, lorsque p53 détecte des dommages à l'ADN, des enzymes de réparation de l'ADN sont recrutées pour corriger les dommages. Si l'ADN n'est pas réparé, p53 déclenche l'apoptose ou la mort cellulaire et empêche la duplication des chromosomes endommagés. L'augmentation du niveau de p53 dans la cellule peut également déclencher la synthèse de p21. La p21 se lie au complexe Cdk/cycline et arrête la progression du cycle. L'accumulation de p53 et de p21 empêche les cellules de passer à la synthèse d'ADN (la phase S). Ce texte est partiellement adapté de <a href="https://openstax.org/books/biology-2e/pages/10-3-control-of-the-cell-cycle">Openstax, Anatomy and Physiology 2e, Section 10.3: Control of the Cell Cycle</a>

Facteurs moléculaires affectant la division cellulaire

Plusieurs facteurs externes et internes influencent l’initiation et l’inhibition de la division cellulaire. Par exemple, la mort de cellules voisines ou la libération de ...

Education

Enseignement

JoVE Core

Anatomy and Physiology

Anatomie et physiologie

Unit 1

Unité 1

Essential Cellular Processes

Processus cellulaires essentiels

KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

cell cycle regulators that control division

Cell division is controlled by outside signals and by internal cell cycle regulators. Nearby cell death can encourage division, and human growth hormone (hGH) can also promote it. In contrast, too little hGH or crowded cells can slow or stop division.

Inside the cell, regulator molecules help each stage finish correctly before the next stage begins. Some regulators act directly on the cycle, while others affect the activity or production of other regulatory proteins. These molecules can either push the cell forward, which is positive regulation, or stop the cycle, which is negative regulation.

The main positive regulators are cyclins and cyclin-dependent kinases, or Cdks. Cdks stay at a constant level, while cyclin levels rise and fall during the cell cycle. The four cyclins are cyclin D, cyclin E, cyclin A, and cyclin B. When cyclins bind tightly to Cdks, the complex becomes active after phosphorylation.

Each cyclin acts at a different point in the cycle. Cyclin D rises in G1, stays high through most of the cycle, and drops in M phase. Cyclin E peaks at the G1-S transition. Cyclin A is high during S and G2, and cyclin B rises as the cell nears M phase and helps drive cell division.

Negative regulators help prevent damaged or uncontrolled division. These include retinoblastoma protein, or Rb, p53, and p21. When p53 detects DNA damage, it recruits DNA repair enzymes. If the damage is not repaired, p53 can trigger apoptosis, or cell death, and prevent damaged chromosomes from being copied.

p53 can also increase p21 synthesis. The p21 protein binds to the Cdk/cyclin complex and blocks cycle progression. Together, p53 and p21 can stop the cell from entering DNA synthesis, which is the S phase.

Cell Cycle Regulators That Control Division

cell-cycle-regulators-that-control-division

the central dogma

Central Dogma: DNA to Protein

The central dogma explains how genetic information flows in cells from DNA to RNA to protein. It is a core idea in molecular biology and helps show how genes influence cell function. DNA stores the instructions. During transcription, a cell copies a gene into RNA, which is a related nucleic acid. That RNA message can then be used in translation to build a protein. Proteins carry out many jobs in cells and help determine traits. The central dogma links the genetic code in DNA to the molecules...

replication in eukaryotes

Eukaryotic DNA Copying at the Replication Fork

Eukaryotic DNA copying happens at replication forks, where the two DNA strands separate and new strands are built. This process lets a cell make an exact copy of its genetic material before it divides. The transcript explains that eukaryotic replication follows the same basic steps seen in other DNA replication systems, but it takes place in cells with a nucleus. The replication machinery works on each separated strand as a template, so the new DNA matches the original sequence. This topic is...

types of rna

RNA Types in Gene Expression

RNA types play different roles in gene expression. RNA, or ribonucleic acid, helps carry and use genetic information in cells. The main types discussed here are messenger RNA, ribosomal RNA, and transfer RNA. Messenger RNA, or mRNA, carries the genetic code from DNA to the ribosome. The ribosome is the site where proteins are made. Ribosomal RNA, or rRNA, is a key part of the ribosome itself. Transfer RNA, or tRNA, brings the correct amino acids to the ribosome during protein building. These...

transcription

Transcription and RNA Synthesis

Transcription is the process of making RNA from a DNA template. It is a key step in gene expression, because cells use the DNA sequence to build an RNA copy that can carry the message forward. During transcription, RNA polymerase binds to DNA and reads one strand as the template. The enzyme links RNA nucleotides together in the correct order to form a growing RNA molecule. This copying step does not make DNA; it produces RNA. The transcript focuses on the central idea of transcription as DNA...

translation

Translation: mRNA to Protein

Translation is the step in gene expression where ribosomes use messenger RNA, or mRNA, to build a protein. The mRNA sequence carries the instructions copied from DNA. During translation, those instructions are read in order so the cell can make a specific chain of amino acids. This process depends on the ribosome and transfer RNA, or tRNA. The ribosome reads the mRNA, and tRNA brings the matching amino acids. As the chain grows, the amino acids are linked together to form a polypeptide, which...

regulation of expression at multiple steps

regulation-of-expression-at-multiple-steps

How Cells Control Gene Expression

Cells control gene expression at several stages, from making RNA to building protein. These checkpoints include transcription, RNA processing, RNA localization, and translation. Together, they help decide when a gene is used and whether a protein is made. Transcription is controlled by regulatory proteins. Transcription factors, activators, and repressors can start or slow the transcription of genes. After transcription, the cell makes a precursor RNA, also called pre-mRNA. Pre-mRNA must be...

what is the cell cycle?

Cell Cycle Stages in Cell Growth

The cell cycle is the process that controls cell growth and division. It explains how one cell makes two new cells. This process helps cells grow and reproduce.

interphase

Interphase and Cell Growth

Interphase is the part of the cell cycle when a cell grows and prepares to divide. It is a major stage of the cell cycle, and it comes before cell division begins. During interphase, the cell carries out its normal functions. It also copies its DNA so each new cell can receive a full set of genetic material. The cell may also build up the materials it needs for division. Interphase is not a single step. It includes phases such as G1, S, and G2, which help the cell grow, copy DNA, and get...

mitosis and cytokinesis

Cell Division: Mitosis and Cytokinesis

Cell division depends on mitosis and cytokinesis. Mitosis is the stage when the cell’s nucleus divides and the copied chromosomes are separated into two sets. Cytokinesis is the step that follows and splits the cell into two daughter cells. These two processes work together to make sure each new cell receives genetic material and its own cytoplasm. Mitosis keeps the chromosome sets organized, while cytokinesis finishes the division of the whole cell. Together, they create two separate cells...

the cell cycle control system

Cell Cycle Checkpoints and Cyclin Control

The cell cycle is controlled by checkpoints that help a cell move from one phase to the next and begin mitosis. This control system uses internal regulatory molecules and outside signals to send stop or advance instructions. It makes sure each step is finished before the cell moves forward. Cyclins and cyclin-dependent kinases, or Cdks, are the main regulators of the cell cycle. They act during the G1, G2, and M phases. These regulators work at specific checkpoints to keep cell division...

molecular factors affecting cell division

Cell division is controlled by outside signals and by internal cell cycle regulators. Nearby cell death can encourage division, and human growth hormone (hGH) can also promote it. In contrast, too little hGH or crowded cells can slow or stop division. Inside the cell, regulator molecules help each stage finish correctly before the next stage begins. Some regulators act directly on the cycle, while others affect the activity or production of other regulatory proteins. These molecules can either...

what is meiosis?

Meiosis and the Formation of Gametes

Meiosis is the cell division process that forms gametes, or sex cells. It reduces the chromosome number so offspring can inherit the correct amount of genetic material. This process includes two successive divisions. First, one cell divides, and then the resulting cells divide again. These steps separate the genetic material in a controlled way. Meiosis helps explain how sexual reproduction passes traits from one generation to the next. It is a key topic in high school biology because it...

overview of cell signaling

Cell Signaling Pathways and Responses

Cell signaling pathways and responses help cells communicate and react to changes. Cells send signals to one another, and those signals can trigger a specific response in the target cell. A signal usually begins when a signaling molecule reaches a cell with the right receptor, which is a protein that receives the message. The receptor helps the cell recognize the signal and start the communication process. Inside the cell, the message can move through a signaling pathway. This pathway passes...

types of signaling molecules

Chemical Messengers in Cell Signaling

Chemical messengers help cells communicate during signaling. These signaling molecules carry information from one cell to another and guide how cells respond. Some signaling molecules are gases, while others are proteins or peptides. Small lipids can also act as signals. In addition, cells may use steroids, amino acids, and even ions as signaling molecules. Each type of signaling molecule has different properties and works in a different way. Together, these molecules let cells send specific...

g protein-coupled receptors

G Protein-coupled Receptor Signaling

G protein-coupled receptors are a major class of cell-surface receptors. They help cells detect signals outside the cell and pass that information inward. These receptors are important in many kinds of cell communication. When a signal binds to a G protein-coupled receptor, the receptor changes shape. That change activates a G protein inside the cell. The activated G protein can then start a signaling pathway. This signaling system includes the receptor, the G protein, and the downstream...

cellular differentiation

From Stem Cell to Specialized Cells

Cellular differentiation turns unspecialized cells into specialized cells with specific jobs. This process helps a complex organism, such as a human, develop from a single fertilized egg into a body with many cell types. Nerve cells, muscle cells, and epithelial cells are examples of the final cell types that appear during development. A zygote is the first cell after fertilization. It is a totipotent stem cell, which means it has very high differentiation potential and can form all cell types...

key terms and concepts

Learn how external signals, cyclins, Cdks, p53, and p21 control cell division and help cells decide when to divide or stop.

Cell Cycle Regulators That Control Division | JoVE K12

anatomy and physiology

JoVE Core Anatomy and Physiology showcases the anatomical and physiological details of the human body in comprehensive, clear, and engaging video animations. This collection of lessons focuses on the structures, components, functions, and requirements of the human body. It is complemented by scientist-in-action videos that demonstrate the application of this knowledge in real-world medical and research settings.

Characteristics of Life

Biology is a natural science that studies life and living organisms, including their structure, function, development, interactions, evolution, ...

https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/10647.jpg

Cell Structure

Background
Cells represent the most basic biological units of all organisms, whether it be simple, single-celled organisms like bacteria, or large, ...

Visualizing Onion and Cheek Cells
ExpandImmediately before the experiment, wash and peel onion bulbs for the class.
Remove the entire brown outer skin and ...

Visualizing Onion and Human Cells
ExpandIn this experiment you will prepare different types of cells from a plant and animal, onion and human ...

What are Cells?

Cell Diversity

The concept of a cell started with microscopic observations of dead cork tissue by Robert Hooke in 1665. Hooke coined the term &#34;cell&#34; based on the ...

Cytoplasm

The cytoplasm consists of organelles and a framework of protein scaffolds called the cytoskeleton suspended in an aqueous solution, the cytosol. The ...

The Nucleus

The nucleus is a membrane-bound organelle that acts as a control center in a eukaryotic cell. It contains chromosomal DNA, which controls gene expression ...

The Central Dogma

The DNA Helix

Nucleic Acids

DNA as a Genetic Template

Structure of a Gene

A gene is the fundamental unit of heredity. Every individual has two copies of each gene, one inherited from each parent. Although most people contain the ...

Chromosome Structure

Base-pairing and DNA Repair

What is Gene Expression?

A gene is a stretch of DNA that serves as the blueprint for functional RNAs and proteins. Since DNA is comprised&#160; of nucleotides and proteins are ...

RNA Structure

The basic structure of RNA consists of a string of ribonucleotides attached by phosphodiester bonds. Although most RNA is single-stranded, it can form ...

Protein Families

Types of RNA

Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs perform diverse ...

Conservation of Protein Domains

Transcription

Transcription is the synthesis of RNA from a DNA sequence by RNA polymerase. It is the first step in producing a protein from a gene sequence. ...

Globular and Fibrous Proteins

Translation

Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following transcription, it constitutes ...

Intrinsically Disordered Proteins

Ribosomes

Ribosomes translate genetic information encoded by messenger RNA (mRNA) into proteins. Both prokaryotic and eukaryotic cells have ribosomes. Cells that ...

Protein Complex Assembly

Protein and Protein Structures

Conjugated Proteins

Proteins: From Genes to Degradation

Amyloid Fibrils

What are Proteins?

Proteins are polymers of amino acids linked together by peptide bonds. Proteins and polypeptides are interchangeably used to refer to long chains of amino ...

Ligand Binding Sites

Protein Organization

Proteins are polymers of amino acid residues. They are versatile and responsible for different cellular functions, including DNA replication, molecular ...

Protein-Protein Interfaces

Protein Folding

Proteins are chains of amino acids linked together by peptide bonds. Upon synthesis, a protein folds into a three-dimensional conformation, critical to ...

Conserved Binding Sites

Cofactors and Coenzymes

Enzymes are proteins made of amino acids. The functional group of each constituent amino acid catalyzes a wide variety of chemical reactions via ionic ...

Cooperative Allosteric Transitions

Protein Kinases and Phosphatases

GTPases and their Regulation

Covalently Linked Protein Regulators

protein-complexes-with-interchangeable-parts

Protein Complexes with Interchangeable Parts

Mechanical Protein Function

Structural Protein Function

Protein Networks

Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins, which carry out the essential functions of life through systems of specialized cells. [Assessment Boundary: Assessment does not include identification of specific cell or tissue types, whole body systems, specific protein structures and functions, or the biochemistry of protein synthesis.]

HS-LS1-1

Levels of Organization

Biological organization is the classification of biological structures, ranging from atoms at the bottom of the hierarchy to the Earth&#x27;s biosphere. ...

Animal and Plant Cell Structure

Animal and plant cells not only differ in their structure, function, and mode of nutrition but also in how they reproduce, specialize, and organize into ...

structural-organization-of-the-human-body-an-overview

Structural Organization of the Human Body: An Overview

It is convenient to consider the body&#39;s structures in terms of fundamental levels of organization that increase in complexity: subatomic particles, ...

Overview of Human Digestion

The human body contains a monogastric digestive system. In a monogastric digestive system, the stomach only contains one chamber in which it digests food. ...

Anatomy of the Intestines

Although digestion of proteins, carbohydrates, and lipids may begin in the stomach, it is completed in the intestine. The absorption of nutrients, water, ...

Accessory Organs

Accessory organs are those that participate in the digestion of food but do not come into direct contact with it like the mouth, stomach, or intestine do. ...

Lipid Digestion

Lipids are large molecules that are generally not water-soluble. Since most of the digestive enzymes in the human body are water-based, there are specific ...

Protein Digestion

Protein digestion begins in the stomach, where the highly acidic environment can easily disrupt protein structure by exposing the peptide bonds of ...

Carbohydrate Digestion

Carbohydrate digestion and metabolism break down simple and complex carbohydrates from food into saccharides (i.e., sugars) for the body to use as energy. ...

What is a Nervous System?

Overview

The nervous system is the collection of specialized cells responsible for maintaining an organism&rsquo;s internal environment and coordinating ...

The Parasympathetic Nervous System

Overview

The parasympathetic nervous system is one of the two major divisions of the autonomic nervous system. This parasympathetic system is responsible ...

The Sympathetic Nervous System

Overview

The sympathetic nervous system&mdash;one of the two major divisions of the autonomic nervous system&mdash;is activated in times of stress. It ...

Oogenesis

In human women, oogenesis produces one mature egg cell or ovum for every precursor cell that enters meiosis. This process differs in two unique ways from ...

What is a Sensory System?

Sensory systems detect stimuli&mdash;such as light and sound waves&mdash;and transduce them into neural signals that can be interpreted by the nervous ...

Fertilization

During fertilization, an egg and sperm cell fuse to create a new diploid structure. In humans, the process occurs once the egg has been released from the ...

What is the Skeletal System?

Overview

The adult human skeleton comprises 206 bones that are connected through cartilage, tendons, and ligaments. The skeleton provides a rigid ...

an-introduction-to-the-zebrafish-danio-rerio

An Introduction to the Zebrafish: Danio rerio

Zebrafish (Danio rerio) are small freshwater fish that are used as model organisms for biomedical research. The many strengths of these fish include their ...

Physiology of the Circulatory System

Homeostasis
Conditions in the external environment of an organism can change rapidly and drastically. To survive, organisms must maintain a fairly ...

Anatomy of the Circulatory System

The human circulatory system consists of blood, blood vessels that carry blood away from the heart, around the body, and back to the heart, and the heart ...

Measuring Blood Pressure
ExpandTo prepare for the blood pressure exercise, simply place the appropriate number of alcohol swabs, sphygmomanometers, and ...

Anatomy of the Heart

The human heart is made up of three layers of tissue that are surrounded by the pericardium, a membrane that protects and confines the heart. The ...

Measuring Circulatory System Function in Humans
ExpandBefore starting the experiment go to the front of the room and collect an alcohol swab, a ...

Blood Flow

Blood is pumped by the heart into the aorta, the largest artery in the body, and then into increasingly smaller arteries, arterioles, and capillaries. The ...

What Are Osmoregulation and Excretion?

Organisms must keep bodily fluids at a constant temperature and pH while maintaining specific solute concentrations in order to support life functions. ...

Blood Withdrawal I

Source: Kay Stewart, RVT, RLATG, CMAR; Valerie A. Schroeder, RVT, RLATG. University of Notre Dame, IN
Blood collection is a common requirement for ...

Kidney Structure

The kidneys are two large bean-shaped organs located in the upper abdomen. They filter the blood several times a day to remove toxins and rebalance water ...

Blood Withdrawal II

Source: Kay Stewart, RVT, RLATG, CMAR; Valerie A. Schroeder, RVT, RLATG. University of Notre Dame, IN
The collection of blood from mice and rats for ...

Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms. [Clarification Statement: Emphasis is on functions at the organism system level such as nutrient uptake, water delivery, and organism movement in response to neural stimuli. An example of an interacting system could be an artery depending on the proper function of elastic tissue and smooth muscle to regulate and deliver the proper amount of blood within the circulatory system.] [Assessment Boundary: Assessment does not include interactions and functions at the molecular or chemical reaction level.]

HS-LS1-2

Cell Cycle Regulators That Control Division

Description

Transcript

Tags

More videos by Standards