Name: phosphorylation and protein control
Uploaded: 2019-03-11T09:21:10.000Z
Duration: 1 min 2 s
Channel: JoVE

K12 Standards

Virginia  Standards of Learning

HIgh School

Life Science

LS.4

LS.4.b

Phosphorylation

Фосфорилирование, добавление фосфатной группы, представляет собой важное изменение для клеточного регулирования функции белка. При удалении фосфатной группы во время гидролиза АТФ, ферменты, которые называются протеин-киназами, могут катализировать ковалентное связывание этой группы с определенной аминокислотой в боковых цепях белка. В результате белок меняет форму или позволяет другим белкам привязываться к фосфорилированным областям.Эти изменения могут изменить функцию белка или даже полностью активировать или деактивировать его. Фосфатную группу можно удалить действием протеин-фосфатазы, ферментов, которые катализируют дефосфорилирование белков, по сути, запуская реакции в обратном направлении. Регулируя таким образом фосфорилирование, активность некоторых белков может быть включена, выключена, или модифицирована так, как это нужно клетке.

Кириакис, Джон М. "В начале было фосфорилирование белка." Журнал биологической химии 289, No14 (4 апреля 2014 г.): 9460–62. [<a href="https://doi.org/10.1074/jbc.R114.557926" target="__blank">Источник</a>]
Ардито, Фатима, Микеле Джулиани, Донателла Перроне, Джузеппе Трояно и Лоренцо Ло Муцио. «Решающая роль фосфорилирования белка в передаче сигналов в клетках и его использование в качестве таргетной терапии (обзор)». Международный журнал молекулярной медицины 40, No 2 (август 2017 г.): 271–80. [<a href="https://doi.org/10.3892/ijmm.2017.3036" target="__blank">Источник</a>]

Фосфорилирование

Добавление или удаление фосфатных групп из белков является наиболее распространенной химической модификацией, которая регулирует клеточные процессы. Эти изменения могут повлиять на структуру, активность, стабильность и локализацию белков в клетках, а также на их взаимодействие с другими белками. 

Во время фосфорилирования белковые киназы передают терминационную фосфатную группу АТФ в специфические аминокислотные боковые цепи субстратных белков. Серин, трионин и тирозин являются наиболее часто фосфорилированными аминокислотами. Соответственно, белковые киназы классифицируются как серин/трионин киназы, тирозинкинасы, или киназы двойного действия, если они могут фосфорилировать все три аминокислоты. И наоборот, белковые фосфаты катализируют удаление фосфатной группы (дефосфорилирование), восстанавливая первоначальные свойства белка.

В физиологических условиях фосфорилирование и дефосфорилирование жестко регулируются для предотвращения длительных изменений в структуре и функции белка. Нарушение этого баланса может вызвать заболевания, в том числе рак и различные нейродегенеративные расстройства. Например, белок под названием тау гиперфосфорилируется при болезни Альцгеймера (AD). Физиологически тау регулирует форму, структуру и развитие нейронов. Белок тау содержит более 80 серинов, трионинов и остатков тирозина, из которых только часть обычно фосфорилируется. В мозгу пациентов с АД тау аномально и чрезмерно фосфорилируется. Это изменяет растворимость белка, образуя токсичные нерастворимые агрегаты, которые приводят к гибели нейронов.

Добавление или удаление фосфатных групп из белков является наиболее распространенной химической модификацией, регулирующей клеточные процессы. Эти модификации...

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Биология

Cellular Processes

Клеточные процессы

Metabolism

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KEY TERMS AND CONCEPTS

ОСНОВНЫЕ ТЕРМИНЫ И ПОНЯТИЯ

phosphorylation and protein control

Phosphorylation helps control how proteins work in cells. It is the addition or removal of phosphate groups, and it is the most common chemical change that regulates cellular processes. These changes can alter a protein’s structure, activity, stability, location inside the cell, and interactions with other proteins.

During phosphorylation, protein kinases move the terminal phosphate group from ATP to a specific amino acid side chain on a target protein. The amino acids most often phosphorylated are serine, threonine, and tyrosine. Protein kinases are grouped as serine/threonine kinases, tyrosine kinases, or dual action kinases when they can phosphorylate all three.

Protein phosphatases carry out the reverse step. They remove the phosphate group in a process called dephosphorylation, which restores the protein’s original properties. In healthy cells, phosphorylation and dephosphorylation are carefully balanced so protein shape and function do not stay changed for too long.

When this balance is disrupted, disease can result. Examples include cancer and several neurodegenerative disorders. Tau is one important example. In healthy neurons, tau helps regulate neuron shape, structure, and development. Tau has more than 80 serine, threonine, and tyrosine sites, but only some are normally phosphorylated. In Alzheimer’s disease, tau becomes hyperphosphorylated, or abnormally over-phosphorylated. This makes the protein less soluble and leads to toxic insoluble aggregates that contribute to neuronal death.

Phosphorylation and Protein Control

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hydrolysis of atp

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phosphorylation

Phosphorylation helps control how proteins work in cells. It is the addition or removal of phosphate groups, and it is the most common chemical change that regulates cellular processes. These changes can alter a protein’s structure, activity, stability, location inside the cell, and interactions with other proteins. During phosphorylation, protein kinases move the terminal phosphate group from ATP to a specific amino acid side chain on a target protein. The amino acids most often...

induced-fit model

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key terms and concepts

Learn how kinases add phosphate groups, phosphatases remove them, and why balanced phosphorylation matters for cell function and diseases like Alzheimer’s.

Phosphorylation and Protein Control | JoVE K12

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Phosphorylation and Protein Control

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