Name: gtpase molecular switches and control
Uploaded: 2023-04-30T18:28:43.000Z
Duration: 2 min 14 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

GTPases and their Regulation

<ol>
	<li>Mishra, A. K. et Lambright, D. G. (2016). Examen invité : Les petites GTPases et leurs GAPs. Biopolymères, 105(8), 431-448.</li>
	<li>Toma-Fukai, S. et Shimizu, T. (2019). Aperçu structurel du mécanisme de régulation des petites GTPases par les FEM. Molécules (Bâle, Suisse), 24(18), 3308.</li>
</ol>

gtpases et leur régulation

Les protéines de liaison aux nucléotides guanine (protéines G), également connues sous le nom de GTPases, sont une superfamille de protéines qui régulent de nombreux processus cellulaires, tels que la signalisation cellulaire, le transport vésiculaire et la régulation de la forme et de la motilité des cellules. La mutation ou le dysfonctionnement de ces protéines peuvent entraîner des maladies. Il existe environ 40 000 protéines G connues qui peuvent être classées en deux groupes : les petites protéines G constituées d'un seul domaine et les grandes protéines G multi-domaines.

Les grandes protéines G, également connues sous le nom de protéines G hétérotrimériques, sont constituées de trois sous-unités : α, β et γ. La sous-unité α possède un domaine conservé qui interagit avec les récepteurs couplés aux protéines G pour assurer la médiation de la signalisation transmembranaire.

Les petites protéines G constituent une sous-unité unique et transmettent des signaux dans toute la cellule par diverses voies. Elles sont divisées en cinq sous-familles basées sur la séquence et la fonction : Ras, Rho, Rab, Ran et Arf. Les mutations de la sous-famille Ras conduisent à la formation de tumeurs cancéreuses dans les poumons, le côlon et le pancréas. La sous-famille Rho régule la réorganisation de l'actine et la dynamique du cytosquelette des microtubules. La sous-famille Rab, la plus grande petite famille de protéines G, régule le transport des vésicules et le trafic membranaire dans les voies sécrétoires et endocytaires. La sous-famille Ran régule le transport nucléocytoplasmique de l'ARN et des protéines à travers l'assemblage et la fonction des pores nucléaires et du fuseau mitotique. La sous-famille Arf est impliquée dans le transport des vésicules et le trafic membranaire.

Les protéines G sont régulées par la liaison GTP/GDP et ont une activité GTPase intrinsèque, ce qui signifie qu'elles peuvent hydrolyser la GTP en GDP. Lorsque la GTP est liée, la protéine G est à l’état « ON », c’est-à-dire que la protéine favorisera les cascades de signalisation dans la cellule. Lorsque la GDP est liée, elle est à l’état « OFF », ce qui provoque l’arrêt de la signalisation. La régulation de l'activation de la protéine G est également assurée par des facteurs d'échange de nucléotides guaninés (GEF), qui contribuent à la dissociation de la GDP, et par des protéines activatrices de la GTPase (GAP) qui stimulent l'hydrolyse de la GTP. De plus, les inhibiteurs de dissociation de la guanine (GDI) peuvent se lier aux petites GTPases et réguler leur emplacement dans la membrane ou le cytoplasme.

GTPases et leur régulation

Les protéines de liaison aux nucléotides de guanine (protéines G), également connues sous le nom de GTPases, sont une superfamille de protéines qui régulent de nombreux processus cellulaires, tels que les cellules ...

Education

Enseignement

JoVE Core

Cell Biology

Biologie cellulaire

Unit 1

Unité 1

Protein Function

Fonction des protéines

KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

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 by other proteins as well. Some proteins help GTPases exchange GDP for GTP, while others speed up GTP breakdown. These regulators make sure GTPases respond at the right time and in the right place.

GTPase Molecular Switches and Control

ligand binding sites

Ligand Binding Sites in Proteins

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protein-protein interfaces

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conserved binding sites

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cooperative allosteric transitions

Allosteric Changes in Protein Shape

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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

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

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protein complexes with interchangeable parts

protein-complexes-with-interchangeable-parts

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mechanical protein function

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structural protein function

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protein networks

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key terms and concepts

Explore how GTPases act as molecular switches and how GTP and GDP binding, plus regulator proteins, control when they are active or inactive.

GTPase Molecular Switches and Control | JoVE K12

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HS-LS1-3

GTPase Molecular Switches and Control

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