Name: cyclins and cdks in the cell cycle
Uploaded: 2019-03-11T09:21:14.000Z
Duration: 1 min 45 s
Channel: JoVE

K12 Standards

Virginia  Standards of Learning

HIgh School

Biology

BIO.3

BIO.3.c

Positive Regulator Molecules

細胞周期は明確に制御されていて 細胞質に見られる サイクリンと サイクリン依存性キナーゼ(CDK)の 2種類のタンパク質の相互作用により 段階的に発達が促進されます デフォルトでは CDKは常に細胞内で 不活性化された形で存在しています 活性化するには 特定のサイクリンに結合する必要があります この複合体が形成されると CDKは標的タンパク質をリン酸化して その機能を変化させ 細胞が次の段階に進むようにします 大半の場合 サイクリンが分解されると CDKは不活性化され 特定の段階の終わりを示します 例えばG1の間に Dと名付けられた ある種類のサイクリンが合成されて CDKに結合します 細胞は別のサイクリンEとして S期に移行し ピークに達し CDKと複合体を形成して DNAの複製を促進します 次いでEは 細胞質酵素によって分解され サイクリンA濃度はS期に増加し G-2まで高く保たれ 活性型複合体の場合には M期への進入を促進します Aが分解された後 サイクリンBの濃度は M期にピークに達し 複合体は有糸分裂の 様々な段階を活性化します Bのレベルが下がると 細胞は有糸分裂を終了して分裂します それで4つの異なる サイクリンのレベルは 予測可能なパターンで変化し 特定の時点で 一貫したCDKと組み合わされて 前に進む勢いが生じます

Bai, Jingwen, Yaochen Li, and Guojun Zhang. "Cell Cycle Regulation and Anticancer Drug Discovery." Cancer Biology & Medicine 14, no. 4 (2017年11月): 348–62.[<a href="https://doi.org/10.20892/j.issn.2095-3941.2017.0033" target="__blank">ソース</a>]

「細胞周期調節因子の免疫調節的役割」 Frontiers in Cell and Developmental Biology 7 (2019).[<a href="https://doi.org/10.3389/fcell.2019.00023" target="__blank">ソース</a>]

正の制御分子

健康な細胞を安定して生産するためには、娘細胞を生み出すプロセスである細胞周期を正確に制御する必要があります。
 
 内部の制御チェックポイントでは、細胞の大きさやエネルギーの蓄え、DNAの質や完成度が、細胞周期を進めるのに十分であることを確認します。
 
 正の制御因子には、細胞が制御チェックポイントを通過するための2つのタンパク質グループ、サイクリンとサイクリン依存性キナーゼ(CDK)があります。これらのタンパク質は、酵母からヒトまでの真核生物に存在します。
 
 サイクリンは、最も関与している細胞周期の期や移行に基づいて、G1、G1/S、S、Mサイクリンに分類されます。一般的に、あるサイクリンの量は、細胞周期の大部分では低く、最も関与するチェックポイントにおいて急激に上昇します（なお、G1サイクリンは例外で、細胞周期全体で必要とされます）。その後、サイクリンは細胞質内の酵素によって分解され、その量は低下します。その間に、次のチェックポイントに必要なサイクリンが蓄積されていきます。 
 
 細胞周期を制御するためには、サイクリンはサイクリン依存性キナーゼ（CDK）と結合する必要があります。CDKは、リン酸基を付加して標的タンパク質の活性を変化させる酵素の一種です。CDKはサイクリンと結合して初めて活性化します。CDKは、結合しているサイクリンに応じて、特定の細胞周期ステージに進むために必要な異なる標的タンパク質に誘導されます。
 
 サイクリンと比較すると、CDKは細胞周期を通じて比較的一定のレベルを保っていますが、細胞周期中のサイクリンの量の変化に応じて、CDKの活性や標的となるタンパク質が変化します。

健康な細胞を一貫して作製するためには、娘細胞を生成するプロセスである細胞周期を正確に制御する必要があります。

国内。。。

Education

JoVE Core

生物学

Cellular Processes

細胞プロセス

Cell Cycle and Division

細胞周期と細胞分裂

KEY TERMS AND CONCEPTS

主要用語と概念

cyclins and cdks in the cell cycle

Cyclins and CDKs help control the cell cycle, the process that produces daughter cells. Cells use internal checkpoints to make sure their size, energy reserves, and DNA are ready before they move forward. At these checkpoints, positive regulators help the cell continue, while negative regulators slow or stop it.

The main positive regulators are cyclins and cyclin-dependent kinases, or CDKs. These proteins are found in eukaryotes, from yeast to humans. Cyclins are grouped by the stage they help control: G1, G1/S, S, or M cyclins. G1 cyclins are unusual because they are needed throughout the cell cycle.

Cyclin levels usually stay low for most of the cycle. They rise sharply at the checkpoint where they are needed most, then enzymes in the cytoplasm break them down and their levels fall. At the same time, the next cyclins begin to build up for later checkpoints.

CDKs are enzymes that add a phosphate group to a target protein. A CDK becomes active only when it is bound to a cyclin. The cyclin it binds helps direct the CDK to the right target proteins for that stage of the cell cycle. CDK levels stay fairly constant, but their activity changes as cyclin levels rise and fall.

Cyclins and CDKs in the Cell Cycle

what is the cell cycle?

Cell Cycle Checkpoints and Cancer

The cell cycle is the set of steps a eukaryotic cell follows as it grows and divides. In somatic cells, it has two main stages: interphase and the mitotic phase. During interphase, the cell grows, carries out its basic metabolic functions, copies its DNA, and gets ready for mitotic cell division. After interphase, the cell enters mitosis and cytokinesis. Mitosis divides the nuclear material, and cytokinesis divides the cytoplasm. These steps produce two daughter cells that are identical to the...

genomic dna in prokaryotes

Prokaryote Chromosomes and Plasmids

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binary fission

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genomic dna in eukaryotes

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interphase

Interphase in the Cell Growth Cycle

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mitosis and cytokinesis

Cell Cycle Stages in Mitosis

Cell cycle stages in mitosis show how a eukaryotic cell copies its DNA and then divides into two daughter cells. The cycle is controlled by regulatory systems and by outside signals that affect cell growth and division. In typical human cells, the full cycle takes about 24 hours and includes two major phases. The first is DNA replication during the S phase of interphase. The second is the mitotic, or M, phase, which includes mitosis and cytokinesis. G1 and G2 are the gap stages between these...

positive regulator molecules

Cyclins and CDKs help control the cell cycle, the process that produces daughter cells. Cells use internal checkpoints to make sure their size, energy reserves, and DNA are ready before they move forward. At these checkpoints, positive regulators help the cell continue, while negative regulators slow or stop it. The main positive regulators are cyclins and cyclin-dependent kinases, or CDKs. These proteins are found in eukaryotes, from yeast to humans. Cyclins are grouped by the stage they help...

negative regulator molecules

Cell Cycle Stop Signals: p53, p21, and Rb

Cell cycle stop signals help control when a cell can move forward through division. Negative regulators pause or end the cell cycle until the cell meets the right conditions. Three well-studied negative regulators are p53, p21, and retinoblastoma protein, or Rb. Their roles became clear after faulty versions were found in cancer cells that kept replicating uncontrollably. These proteins act mostly at the G1 checkpoint, which comes early in the cell cycle. P53 has a strong effect on whether a...

cancer

Cancer Treatment, Personalization, and Cell Growth

Cancer develops when mutations affect genes that control cell division. Those changes can remove the normal brakes on growth and lead to uncontrolled cell proliferation. Modern science and medicine have improved how cancer is understood and treated, and some patients can now be cured. There is still no single cure for cancer because cancer is not one disease. It is a large group of many diseases. Even when two people have the same mutation in an oncogene or a tumor suppressor gene, their...

key terms and concepts

Learn how cyclins and CDKs regulate cell cycle checkpoints, with cyclin types, changing levels, and how CDKs are activated to move cells forward.

Cyclins and CDKs in the Cell Cycle | JoVE K12

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JoVE Core シリーズは、生物学の重要な概念を説明する 300 を超える簡潔でわかりやすいアニメーション ビデオ レッスンに加え、今日の研究室で行われる実際の研究実験を示す 150 以上の科学者の活動ビデオを通じて、生物学に命を吹き込みます。

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

Texas Essential Knowledge and Skills

BIO.6

BIO.6.A

new-york-state-science-learning-standards

New York State Science Learning Standards

Inheritance and Variation of Traits

HS-LS1-4.

Georgia Standards of Excellence

9-12

SB1.b

myJoVE Corporation

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BIO.3.e

Cyclins and CDKs in the Cell Cycle

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