Name: protein regulation by covalent bonds
Uploaded: 2023-04-30T18:28:43.000Z
Duration: 2 min 4 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

Covalently Linked Protein Regulators

Многие белки регулируются молекулами, связанными ковалентно, включая функциональные группы, например, метил или ацетил, части молекул и малые белки, такие как убиквитин. Осуществляются ковалентные связи на специальных аминокислотах в полипептидной цепи. Например, фосфатные группы ковалентно связаны с серином, треонином, или тирозином.Метиловые и ацетильные группы связаны с лизином. А убиквитин связан с. лизиновыми, цистиновыми, сериновыми, или треониновыми остатками.Фермент или пара ферментов обратимо катализируют эти пост-трансляционные модификации. И ацетилтрансфераза может ацетилизировать белок, в то время как диацетилаза может позднее убрать эту группу. Эти изменения могут подправить функцию белка или локализацию в клетке.Например, ацетилирование белков гистона регулирует экспрессию генов путём открытия структуры ДНК для активации функции генной транскрипции. Метилирование белков гистона, с другой стороны, известно, как подавляющее транскрипцию путем подтягивания структуры. Другой пример р53, белк-супрессор многих основных опухолей, который претерпевает несколько ковалентных модификаций в ответ на стресс.Воздействие агентами, повреждающими ДНК, например, ультрафиолетовым и гамма-излучением, может привести к фосфорилированию белка. Фосфорилирование улучшает стабильность и активирует p53, заставляя его связываться с ДНК, повреждённой излучением для клеток с мутировавшей ДНК предотвращает бесконтрольное деление. Помимо фосфорилирования, различные типы модификаций, возникающих в одиночной белковой молекуле, такой как p53, позволяет ему точно контролировать функции, такие, как остановка клеточного цикла, ремонт ДНК и апоптоз клетки.

<ol>
	<li>Идентификатор 1PDB: 1UBQ 
	Виджай-Кумар, С., Багг, С.Э., Кук, В.Д. (1987) Структура убиквитина, уточненная при разрешении 1,8 А. J Mol Biol 194: 531-544. DOI: 10.1016/0022-2836(87)90679-6</li>
	<li>Х.М. Берман, Д. Уэстбрук, З. Фенг, Г. Гиллиленд, Т.Н. Бхат, Х. Вайссиг, И.Н. Шиндялов,.Е. Борн. (2000) Исследование нуклеиновых кислот в банке данных о белках, 28: 235-242.</li>
	<li>Д. Сенал, А.С. Роуз, Д. Ковча, С.К. Берли, С. Веланкар (2018) Mol*: На пути к общей библиотеке и инструментам для веб-молекулярной графики MolVA/EuroVis Proceedings. doi:10.2312/molva.20181103</li>
	<li>Альбертс и др., 6-е издание; стр. 157-158, 165-166</li>
	<li>Ле, Д. Д., и Фухимори, Д. Г. (2012). Ферменты метилирования белков и нуклеиновых кислот: механизмы и регуляция. Современное мнение в химической биологии, 16(5-6), 507–515. DOI:10.1016/j.cbpa.2012.09.014</li>
	<li>Хидекель, Н., и Шей-Уилсон, Л. С. (2004). «Молекулярный коммутатор» — ковалентные модификации белков и их влияние на транскрипцию. Органическая и биомолекулярная химия, 2(1), 1-7.</li>
	<li>Маклейн, Н. Дж., и Хапп, Т. Р. (2009). Регуляция p53 путем фосфорилирования: модель того, как различные сигналы интегрируются в путь p53. Старение, 1(5), 490.</li>
</ol>

Ковалентно связанные регуляторы белка

Белки могут подвергаться множеству типов посттрансляционных модификаций, часто в ответ на изменения в их среде. Эти модификации играют важную роль в функции и стабильности этих белков. Ковалентно связанные молекулы включают функциональные группы, такие как метильные, ацетильные и фосфатные группы, а также небольшие белки, такие как убиквитин. Идентифицировано около 200 различных типов ковалентных регуляторов.Эти группы модифицируют определенные аминокислоты в белке. Фосфатные группы могут быть ковалентно присоединены только к аминокислотам - серину, треонину и тирозину, тогда как метильные и ацетильные группы могут быть связаны только с лизином. Эти группы добавляются к белку и удаляются из него с помощью фермента или пары ферментов. Например, ацетилтрансфераза добавляет к белку ацетильную группу, а деацетилаза может ее удалить. Каждый из этих модификаторов может оказывать различное воздействие на белок, к которому он присоединен, в зависимости от количества и местоположения модификаций. Когда одна молекула убиквитина ковалентно связана с определенным рецептором клеточной поверхности, этот белок подвергается эндоцитозу; с другой стороны, когда к этому белку присоединяются несколько убиквитинов, связанных вместе, он помечается как мишень для протеолитической деградации.Один белок может подвергаться нескольким модификациям одновременно, чтобы контролировать его функцию. Одним из хорошо известных примеров белка, регулируемого множественными ковалентными модификациями, является белок-супрессор опухолей р53. р53 претерпевает множество модификаций в ответ на различные виды стресса, включая радиацию и канцерогены. Некоторые модификации включают фосфорилирование, ацетилирование и сумойлирование в ответ на УФ- и гамма-излучение. Места и типы модификаций могут варьироваться в зависимости от стрессора. Исследования показали, что УФ- и гамма-излучение могут приводить к фосфорилированию серина 33, но серин 392 может фосфорилироваться под воздействием УФ-излучения, но не гамма-излучения. Другие виды стресса, такие как воздействие гипоксии, антиметаболитов и актиномицина D, могут привести к ацетилированию р53. Модификации также могут различаться в зависимости от типа клеток и организмов.

Белки могут подвергаться многим типам посттрансляционных модификаций, часто в ответ на изменения в окружающей их среде. Эти модификации играют важную роль...

Education

JoVE Core

Cell Biology

Клеточная биология

Unit 1

Раздел 1

Protein Function

Функции белков

KEY TERMS AND CONCEPTS

ОСНОВНЫЕ ТЕРМИНЫ И ПОНЯТИЯ

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 regulators are an important part of cell control and signaling. They help cells turn protein functions on or off at the right time. This type of regulation is a key idea in molecular biology and protein function.

Protein Regulation by Covalent Bonds

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 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-with-interchangeable-parts

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...

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

Learn how covalent bonds can regulate proteins by changing activity, location, and stability. A clear K12 summary of protein control in cells.

Protein Regulation by Covalent Bonds | 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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Cell Structure

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The Nucleus

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Nucleic Acids

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Globular and Fibrous Proteins

Translation

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Intrinsically Disordered Proteins

Ribosomes

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Protein Complex Assembly

Protein and Protein Structures

Conjugated Proteins

Proteins: From Genes to Degradation

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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

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Cooperative Allosteric Transitions

Protein Kinases and Phosphatases

GTPases and their Regulation

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.]

Levels of Organization

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Overview of Human Digestion

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Carbohydrate Digestion

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The Parasympathetic Nervous System

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The Sympathetic Nervous System

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Homeostasis
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Measuring Circulatory System Function in Humans
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Blood Flow

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Blood Withdrawal I

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Kidney Structure

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Blood Withdrawal II

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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

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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

Protein Regulation by Covalent Bonds

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