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

Phosphorylierung, der Zusatz zu einer Phosphatgruppe, ist eine wichtige Veränderung für Zellen um ihre Proteinfunktionen zu regulieren.
 Wenn eine Phosphatgruppe während einer ATP Hydrolyse entfernt wird, können Enzyme namens Proteinkinasen die kovalente Bindung dieser Gruppe zu bestimmten Aminosäureseitenketten in einem Protein katalysieren.
 Als Resultat verändert das Protein seine Form, um anderen Proteinen zu erlauben, phosphorylierte Regionen zu binden.
 Diese Änderungen können die Funktion eines Proteins ändern oder es sogar komplett aktivieren oder deaktivieren.
 Die Phosphatgruppe kann durch den Einsatz von Proteinphosphatasen entfernt werden, Enzyme, die die Dephosphorylierung von Proteinen katalysieren, was im Prinzip die Reaktion umkehrt.
 Durch die Regulierung der Phosphorilierung auf diese Art, kann die Aktivität von bestimmten Proteinen umkehrbar an und ausgeschaltet oder modifiziert werden, wie von der wie von der Zelle benötigt.

Kyriakis, John M. "Am Anfang gab es die Proteinphosphorylierung." Das Journal für Biologische Chemie 289, Nr. 14 (4. April 2014): 9460–62. [<a href="https://doi.org/10.1074/jbc.R114.557926" target="__blank">Quelle</a>]
Ardito, Fatima, Michele Giuliani, Donatella Perrone, Giuseppe Troiano und Lorenzo Lo Muzio. "Die entscheidende Rolle der Proteinphosphorylierung bei der Zellsignalisierung und ihre Verwendung als zielgerichtete Therapie (Übersichtsarbeit)." International Journal of Molecular Medicine 40, Nr. 2 (August 2017): 271–80. [<a href="https://doi.org/10.3892/ijmm.2017.3036" target="__blank">Quelle</a>]

phosphorylierung

Das Hinzufügen oder Entfernen von Phosphatgruppen in Proteinen ist die häufigste chemische Modifikation, welche zelluläre Prozesse reguliert. Diese Modifikationen können die Struktur, Aktivität, Stabilität und Lokalisierung von Proteinen innerhalb der Zelle sowie deren Wechselwirkungen mit anderen Proteinen beeinflussen. 
 
 Bei der Phosphorylierung übertragen Proteinkinasen die terminale Phosphatgruppe von ATP auf spezifische Aminosäureseitenketten von Substratproteinen. Serin, Threonin und Tyrosin sind die am häufigsten phosphorylierten Aminosäuren. Entsprechend werden Proteinkinasen als Serin-/Threonin-Kinasen, Tyrosinkinasen oder multifunktionelle Kinasen klassifiziert, wenn sie alle drei Aminosäuren phosphorylieren können. Umgekehrt katalysieren Proteinphosphatasen die Entfernung der Phosphatgruppe (Dephosphorylierung) und stellen so die ursprünglichen Eigenschaften des Proteins wieder her.
 
 Unter physiologischen Bedingungen sind Phosphorylierung und Dephosphorylierung streng reguliert, um langanhaltende Veränderungen der Proteinstruktur und-funktion zu verhindern. Eine Störung dieses Gleichgewichts kann Krankheiten, einschließlich Krebs und verschiedene neurodegenerative Störungen, verursachen. Bei einer Alzheimererkrankung wird das Protein Tau beispielsweise hyperphosphoryliert. Physiologisch gesehen reguliert Tau die Form, Struktur und Entwicklung von Nervenzellen. Das Tau-Protein enthält über 80 Serin-, Threonin-und Tyrosinreste, von denen normalerweise nur ein Bruchteil phosphoryliert ist. In den Gehirnen von Alzheimer-Patienten wird Tau ungewöhnlich und übermäßig phosphoryliert. Dies verändert die Löslichkeit des Proteins und bildet toxische unlösliche Aggregate, die zum neuronalen Zelltod führen.

Phosphorylierung

Das Hinzufügen oder Entfernen von Phosphatgruppen aus Proteinen ist die häufigste chemische Modifikation, die zelluläre Prozesse reguliert. Diese Modifikationen ...

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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...

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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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