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

- [Eğitici] Fosforilasyon, yani bir fosfat grubunun eklenmesi, hücrelerin protein işlevini düzenlemesi için önemli bir modifikasyondur.
 ATP hidrolizi sırasında bir fosfat grubu uzaklaştırıldığında protein kinaz adı verilen enzimler bu grubun bir protein içindeki belirli amino asit yan zincirlerine kovalent bağlanmasını katalize edebilir.
 Sonuç olarak, protein şekil değiştirir veya başka proteinlerin fosforlanmış bölgeleri bağlamasına izin verir.
Bu değişiklikler bir proteinin işlevini değiştirebilir ve hatta onu tamamen aktive edebilir veya deaktive edebilir.
 Fosfat grubu, proteinlerin fosforilasyonunu katalize eden enzimler olan protein fosfatazların etkisiyle, esas olarak reaksiyonu tersine çevirerek uzaklaştırılabilir.
 Bu şekilde fosforilasyonu düzenleyerek, belirli proteinlerin aktivitesi, hücrede gerektiğinde tersine çevrilebilir şekilde açılıp kapatılabilir veya değiştirilebilir.

Kyriakis, John M. "Başlangıçta protein fosforilasyonu vardı." Biyolojik Kimya Dergisi 289, no. 14 (4 Nisan 2014): 9460–62. [<a href="https://doi.org/10.1074/jbc.R114.557926" target="__blank">Kaynak</a>]
Ardito, Fatima, Michele Giuliani, Donatella Perrone, Giuseppe Troiano ve Lorenzo Lo Muzio. "Protein Fosforilasyonunun Hücre Sinyallemesinde Kritik Rolü ve Hedefe Yönelik Tedavi Olarak Kullanımı (Derleme)." Uluslararası Moleküler Tıp Dergisi 40, no. 2 (Ağustos 2017): 271–80. [<a href="https://doi.org/10.3892/ijmm.2017.3036" target="__blank">Kaynak</a>]

fosforilasyon

Fosfat gruplarının proteinlere eklenmesi veya uzaklaştırılması, hücresel süreçleri düzenleyen en yaygın kimyasal modifikasyondur. Bu modifikasyonlar, proteinlerin hücrelerdeki yapısını, aktivitesini, stabilitesini ve lokalizasyonunu ve diğer proteinlerle etkileşimlerini etkileyebilir. 

 Fosforilasyon sırasında protein kinazlar, ATP'nin terminal fosfat grubunu substrat proteinlerinin spesifik amino asit yan zincirlerine aktarır. Serin, treonin ve tirozin en yaygın fosforile amino asitlerdir. Buna göre protein kinazlar, üç amino asidi de fosforile edebiliyorlarsa serin / treonin kinazlar, tirosin kinazlar veya ikili etkili kinazlar olarak sınıflandırılır. Tersine, protein fosfatazlar fosfat grubunun uzaklaştırılmasını (defosforilasyon) katalize ederek proteinin orijinal özelliklerini geri yükler. 

 Fizyolojik koşullar altında, fosforilasyon ve defosforilasyon, protein yapısında ve işlevinde uzun süreli değişiklikleri önlemek için sıkı bir şekilde düzenlenir. Bu dengenin bozulması, kanser ve çeşitli nörodejeneratif bozukluklar gibi hastalıklara neden olabilir. Örneğin, Alzheimer hastalığında (AD) tau adlı bir protein hiperfosforile edilir. Fizyolojik olarak tau, nöronların şeklini, yapısını ve gelişimini düzenler. Tau proteini 80'den fazla serin, treonin ve tirozin kalıntısı içerir ve bunların sadece bir kısmı genellikle fosforile edilir. AD'li hastaların beyinlerinde tau anormal ve aşırı derecede fosforillenmiştir. Bu, proteinin çözünürlüğünü değiştirir ve nöronal ölüme yol açan toksik çözünmez kümeler oluşturur.

Fosforilasyon

Proteinlerden fosfat gruplarının eklenmesi veya çıkarılması, hücresel süreçleri düzenleyen en yaygın kimyasal modifikasyondur. Bu değişiklikler ...

Education

JoVE Core

Biology

Biyoloji

Cellular Processes

Hücresel Süreçler

Metabolism

Metabolizma

KEY TERMS AND CONCEPTS

TEMEL TERİMLER VE KAVRAMLAR

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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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.

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Phosphorylation and Protein Control

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