Name: modular protein complexes in cells
Uploaded: 2023-04-30T18:28:43.000Z
Duration: 1 min 57 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-LS1-1

protein-complexes-with-interchangeable-parts

Protein Complexes with Interchangeable Parts

단백질 복합체는 여러 개의 비공유 결합 단백질로 구성되며, 각 구성 요소는 복합체에 다른 기능을 제공합니다. 
이러한 개별 단백질 중 하나 이상은 밀접하게 관련된 변이체로 대체되어 기능적으로 구별되는 대체 복합체를 생성할 수 있습니다.
유기체가 진화함에 따라 유익한 단백질의 유전자가 게놈 내에서 복제될 수 있습니다. 이 복제된 사본은 원래 단백질의 기능에 영향을 미치지 않고 자유롭게 돌연변이를 겪을 수 있습니다. 
이러한 돌연변이는 관련 단백질의 계열(family)을 생성한다. 이것은 세포가 교체 가능한 부분을 포함하는 단백질 복합체를 생성할 수 있는 방법 중 하나입니다. 
SCF 유비퀴틴 리가제는 5개의 소단위로 구성된 다중체 단백질입니다. 그 기능은 유비퀴틴 분자를 표적 단백질에 부착하여 단백질 분해 효소에 의한 분해를 표시하는 것입니다. 
단백질의 소단위 중 하나인 F-box는 표적 단백질에 결합하는 역할을 하며, 상호 교환이 가능한 여러 변형체를 가지고 있습니다. 이 소단위체의 변화는 복합체가 다른 단백질의 분해를 표시할 수 있도록 합니다. 
일반적으로 빵 효모로 알려진 맥주효모(Saccharomyces cerevisiae)는 11가지 변형의 F-box subunit을 가지고 있어 리가아제가 다양한 세포 과정에 관여하는 단백질을 표시할 수 있습니다.
예를 들어, cdc4 F-box 단백질은 세포주기를 촉진하는 효소를 억제하는 Sic1 및 Far1과 같은 세포주기 조절자를 표적으로 합니다.이들의 분해는 세포주기가 진행되도록 합니다. 
유기체에 걸친 F-box의 변화는 유사한 기능을 가지고 있지만 뚜렷한 표적을 가진 수백 개의 별개의 복합체를 생성합니다.

<ol>
	<li>Alberts et al., 6판; 159-160페이지</li>
	<li>Kipreos, E. T., & Pagano, M. (2000). F-box 단백질 계열. 게놈 생물학, 1(5), REVIEWS3002. doi:10.1186/gb-2000-1-5-리뷰300</li>
</ol>

교체 가능한 부품을 가진 단백질 복합체

단백질 그룹은 복합체를 형성할 수 있으며 이 복합체의 각 단백질은 복합체 기능의 전반적인 실행에서 서로 다른 역할을 합니다. 종종 복합체의 일부 단백질은 밀접하게 관련된 변이체로 대체되어 동일한 구성 요소를 많이 포함하지만 기능적으로는 구별되는 복합체를 생성할 수 있습니다.

SCF 유비퀴틴 리가제는 5개의 개별 단백질로 구성된 단백질 복합체입니다. 이 복합체는 유비퀴틴을 다른 표적 단백질에 부착하여 분해를 표시합니다. 이 기능을 수행하기 위해 단백질 중 하나인 F-박스는 기질에 결합하는 역할을 담당하여 복합체의 다른 단백질인 유비퀴틴 결합 효소가 기질에 접근하여 유비퀴틴을 부착할 수 있도록 합니다. F-box 단백질은 복합체가 다양한 기질을 인식할 수 있도록 여러 개의 상호 교환 가능한 변이체를 가지고 있습니다. 또한, 서로 다른 유기체는 서로 다른 F-box 단백질 변종 세트를 가질 수 있습니다. 인간에게는 38개의 알려진 변종이 있고, 사카로미세스 세레비시아에는 11개, 초파리에는 22개, 예쁜꼬마선충에는 326개의 변종이 있습니다. 이러한 변종을 통해 복합체는 구성 요소 중 하나만 변경하여 광범위한 단백질 스펙트럼을 표적으로 삼을 수 있습니다.

이러한 상호 교환 가능한 변종은 종종 유전자 복제의 결과입니다. 분자 진화 동안 유익한 단백질의 유전자는 이소성 재조합, 복제 미끄러짐, 이수성, 배수성 및 역전위와 같은 이유로 인해 DNA 복제 중에 때때로 복제될 수 있습니다. 이러한 복제된 유전자 복사본은 돌연변이가 원래 유전자의 기능에 영향을 미치지 않기 때문에 한 세대에서 다음 세대로 전달되는 동안 추가로 돌연변이를 겪을 수 있습니다. 이러한 돌연변이는 기능적으로 유사하지만 기질 특이성이 다른 F-박스와 같은 단백질을 담당하는 유전자의 변이체를 생성합니다.

단백질 그룹은 이 복합체의 각 단백질이 복합체 기능의 전체 실행에서 다른 역할을 하는 복합체를 형성할 수 있습니다. ...

Education

교육

JoVE Core

Cell Biology

세포생물학

Unit 1

제1단원

Protein Function

단백질 기능

KEY TERMS AND CONCEPTS

주요 용어 및 개념

modular protein complexes in cells

Protein complexes in cells can be built from interchangeable parts. This modular design lets some complexes share common subunits while still changing their behavior.

A well-known example is the ubiquitin ligase complex called SCF. SCF stands for Skp1-Cullin-F-box, and it helps attach ubiquitin, a small protein tag, to target proteins. The core of SCF stays the same, but the F-box protein can change.

The interchangeable F-box subunit gives the complex its specificity. Different F-box proteins recognize different target proteins. This lets one core complex act on many different targets.

This kind of protein complex shows how cells use shared building blocks to create functional variety. By swapping one part, the same basic structure can take on new roles in protein control.

Modular Protein Complexes in Cells

ligand binding sites

Ligand Binding Sites in Proteins

Ligand binding sites are specific parts of a protein where a ligand can attach. A ligand is a molecule that binds to another molecule, often to help start or change a biological process. These sites matter because the shape and chemistry of the protein help determine which ligands can fit and bind. Proteins do not bind every ligand in the same way. The binding site provides a matching surface that supports a close interaction. In many cases, this interaction is important for how cells respond...

protein-protein interfaces

Protein Binding Surfaces and Contacts

Protein binding surfaces and contacts help proteins recognize and attach to each other. These interfaces are the regions where two proteins meet and interact. They are important for many cell processes and for how proteins work together. A protein-protein interface is not just a random touch point. It is shaped by the three-dimensional form of each protein. The matching surfaces allow a stable interaction to form when the proteins fit together well. Studying these interfaces helps explain how...

conserved binding sites

Conserved Binding Sites in Protein Families

Conserved binding sites are regions on proteins that stay similar across related proteins. These shared areas often help proteins interact with the same molecules. For this reason, they are useful clues when comparing protein families. A conserved site can help identify where a protein binds. It can also show which parts of the protein are important for function. When the same pattern appears in several proteins, it suggests that the site has been kept through evolution. Scientists look at...

cofactors and coenzymes

Enzyme Helpers: Metals and Vitamins

Enzyme helpers include cofactors and coenzymes. Enzymes are proteins made of amino acids, and the functional groups on those amino acids can drive many chemical reactions through ionic interactions or acid-base reactions. But amino acids alone cannot handle oxidation-reduction and group transfer reactions, so they need non-protein helpers called cofactors. Cofactors are often described as the chemical teeth of an enzyme. They can be metal ions or organic molecules called coenzymes. These...

cooperative allosteric transitions

Allosteric Changes in Protein Shape

Allosteric changes in protein shape help explain how some proteins switch between active and inactive states. These transitions are cooperative, which means a change in one part of the protein can affect other parts of the same molecule. The video focuses on how these shifts in shape support protein function. It also shows that allosteric transitions can be described with different models. In the concerted model, the protein changes shape as a whole. In the sequential model, the change happens...

protein kinases and phosphatases

Protein Kinases and Phosphatases in Cell Control

Protein kinases and phosphatases help control how proteins work in cells. Kinases add phosphate groups to proteins. Phosphatases remove those phosphate groups. This phosphorylation and dephosphorylation process can change a protein’s shape and activity. It is one way cells turn protein function on or off at the right time. These changes also help cells respond to signals and manage many cell activities. Together, protein kinases and phosphatases keep cellular signaling balanced. When one adds...

gtpases and their regulation

GTPase Molecular Switches and Control

GTPases are molecular switches that help control cell activity. They bind guanosine triphosphate, or GTP, and can change between active and inactive states. This switch-like behavior makes them important in many cell processes. The protein is active when GTP is bound and inactive when guanosine diphosphate, or GDP, is bound. GTPases can also turn themselves off by breaking down GTP into GDP. This built-in control helps cells regulate when the protein is on or off. Their activity is regulated...

covalently linked protein regulators

Protein Regulation by Covalent Bonds

Protein regulation by covalent bonds helps control how cells respond to changing conditions. A covalent bond is a strong chemical link, and in this context it can change how a protein behaves. Some regulators work by attaching a chemical group directly to a protein. This covalent change can alter the protein's activity, its location in the cell, or how long it stays active. Because the change is built into the protein itself, it can have a strong effect on cell function. Covalently linked...

protein complexes with interchangeable parts

Protein complexes in cells can be built from interchangeable parts. This modular design lets some complexes share common subunits while still changing their behavior. A well-known example is the ubiquitin ligase complex called SCF. SCF stands for Skp1-Cullin-F-box, and it helps attach ubiquitin, a small protein tag, to target proteins. The core of SCF stays the same, but the F-box protein can change. The interchangeable F-box subunit gives the complex its specificity. Different F-box proteins...

mechanical protein function

Proteins That Generate Cell Movement

Mechanical proteins help cells and tissues move. They turn chemical energy into force and motion. This process is important in many biological systems. These proteins are also called motor proteins. They interact with cell structures and can produce directed movement. In muscle cells, they support contraction. In other cells, they help with transport and shape changes. Mechanical protein function is a key part of how living systems work. It links protein activity to movement at the cellular...

structural protein function

Structural Proteins in Cells and Tissues

Structural proteins help cells and tissues keep their shape and strength. They are an important part of living systems because they provide support where it is needed most. Many structural proteins form fibers or other sturdy forms that resist stretching and wear. These proteins work as building materials in the body and help keep structures stable over time. Examples of structural proteins include collagen, actin, myosin, and keratin. Each one supports a different part of the body, but all...

protein networks

Mapping Protein Interaction Networks

Protein interaction networks show how proteins work together inside a cell. These networks help scientists see which proteins connect with each other and how those links support cell activity. Researchers often use online tools to build and study these networks. The transcript points to IntAct and STRING as examples of resources that can help predict and organize protein interactions. These tools make it easier to compare protein links and look for patterns in the network. Protein networks...

key terms and concepts

Explore how cells build protein complexes from interchangeable parts, including the SCF ubiquitin ligase and its F-box subunit that determines target specificity.

Modular Protein Complexes in Cells | JoVE K12

cell biology

JoVE Core Cell Biology illustrates complex cellular processes in easy-to-understand yet comprehensive animated video lessons. This collection focuses on the essential components and functions of cells, including organelles and membranes, cellular transport, and cell energetics. It is complemented by scientist-in-action videos that demonstrate the application of cell biology in real-world research experiments.

Characteristics of Life

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Cytoplasm

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The Nucleus

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The Central Dogma

The DNA Helix

Nucleic Acids

DNA as a Genetic Template

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Conservation of Protein Domains

Transcription

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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

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Protein Complex Assembly

Protein and Protein Structures

Conjugated Proteins

Proteins: From Genes to Degradation

Amyloid Fibrils

What are Proteins?

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Ligand Binding Sites

Protein Organization

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Protein-Protein Interfaces

Protein Folding

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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

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.]

Levels of Organization

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Overview of Human Digestion

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Carbohydrate Digestion

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What is a Nervous System?

Overview

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The Parasympathetic Nervous System

Overview

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The Sympathetic Nervous System

Overview

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Fertilization

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Physiology of the Circulatory System

Homeostasis
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Measuring Circulatory System Function in Humans
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Blood Flow

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What Are Osmoregulation and Excretion?

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Blood Withdrawal I

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Kidney Structure

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Blood Withdrawal II

Source: Kay Stewart, RVT, RLATG, CMAR; Valerie A. Schroeder, RVT, RLATG. University of Notre Dame, IN
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Overview

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Bone Remodeling

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Within the skeletal system, the structure of a bone, or osseous tissue, can be exemplified in a long bone, like the femur, where there are two types of ...

Breathing

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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

What is Homeostasis?

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Negative and Positive Feedback

Homeostatic Imbalance

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Plan and conduct an investigation to provide evidence that feedback mechanisms maintain homeostasis. [Clarification Statement: Examples of investigations could include heart rate response to exercise, stomate response to moisture and temperature, and root development in response to water levels.] [Assessment Boundary: Assessment does not include the cellular processes involved in the feedback mechanism.]

HS-LS1-3

Modular Protein Complexes in Cells

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