Video Experimental Relacionado
Updated: Aug 19, 2026
10:27
Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells
Published on: March 9, 2012
Los dominios de especificidad distinguen las GTPasas Ypt1 y Sec4 relacionadas con Ras
B Dunn1, T Stearns, D Botstein
1Department of Genetics, Stanford University School of Medicine, California 94305.
Nature
|April 8, 1993
Resumen
Los investigadores identificaron un segmento clave de 9-residuo en Ypt1 GTPasa que le permite realizar funciones tanto de Ypt1 como de Sec4 en la secreción de levadura. Este hallazgo avanza en la comprensión de la función y el transporte de proteínas.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Biología celular Biología celular.
- La bioquímica es la bioquímica.
Sus antecedentes:
- Ypt1 y Sec4 son GTPasas esenciales relacionadas con Ras en la levadura Saccharomyces cerevisiae.
- Ypt1 media entre el retículo endoplasmático y el transporte de Golgi, mientras que Sec4 es crucial para la fusión de las vesículas en la membrana plasmática.
Objetivo del estudio:
- Para identificar segmentos específicos de proteínas responsables de las distintas funciones de Ypt1 y Sec4.
- Para comprender la relación estructura-función de estas GTPasas en la vía de secreción.
Principales métodos:
- Construcción y análisis de proteínas quiméricas de la GTPasa.
- Ensayos funcionales in vivo en el Saccharomyces cerevisiae.
Principales resultados:
- Un segmento de 9 residuos de Ypt1 (bucle L7) sustituido en Sec4 confería una doble funcionalidad mínima.
- Un segmento de Ypt1 de 24 residuos más grande, incluyendo el bucle L7 y la región efector (bucle L2), convirtió completamente Sec4 en una proteína funcional de Ypt1.
Conclusiones:
- Regiones específicas, particularmente el bucle L7 y la región efector, dictan los roles distintos de Ypt1 y Sec4.
- Este estudio proporciona información sobre la divergencia funcional y la especificidad de las GTPasas relacionadas con Ras en el transporte vesicular.
Videos de Conceptos Relacionados
02:14GTPases and their Regulation
Guanine nucleotide-binding proteins (G-proteins), also known as GTPases, are a superfamily of proteins that regulate many cellular processes, such as cell signaling, vesicular transport, and the regulation of cell shape and motility. Mutation or dysfunction of these proteins can lead to disease. There are around 40,000 known G-proteins that can broadly be classified into two groups ‒ small G-proteins consisting of a single domain and large multi-domain G-proteins.
Large G-proteins, also known...
Large G-proteins, also known...
01:33Coat Assembly and GTPases
Vesicles incorporate different coat protein subunits in different cell locations, which changes the properties of the coat, such as the shape and geometry of the transport vesicles. Thus, vesicle coat proteins also play a significant role in cargo selection.
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
01:14Rab Proteins
Rab proteins constitute the largest family of monomeric GTPases, of which 70 members are present in humans. Rab proteins and their effectors regulate consecutive stages of vesicle transport such as vesicle transport, docking, and fusion to the correct recipient membrane.
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
01:45Tail-anchoring of Proteins in the ER Membrane
Tail-anchored, or TA, proteins are estimated to make up to 3-5% of membrane proteins found in the eukaryotic cell. Such proteins have a single transmembrane domain located approximately 30 amino acid residues upstream from the C-terminal end. As a result, the signal recognition particle (SRP) cannot guide a TA protein to the ER membrane for cotranslational insertion. Hence, they are integrated into the ER membrane post-translationally using their C-terminal end as the anchor. TA proteins...
01:25Rab Cascades
Rab GTPases act in a regulated cascade during membrane fusion, helping the lipid bilayers mix. The Rab family of proteins are active when bound to GTP, and inactive when bound to GDP. Hence, they act as guanine nucleotide-dependent molecular switches. Rab-GTP recognizes and binds to long or short-range tethering proteins to capture the target vesicle. These tethers coordinate with SNAREs on the vesicle and the target membrane to assemble the trans SNARE complex that locks the mixing bilayers.
01:24Small GTPases - Ras and Rho
Ras and Rho are small monomeric GTPases that act downstream of receptor tyrosine kinase (RTK) and regulate various cellular processes. These GTPases switch between active and inactive states by binding to guanine nucleotides.
Three regulatory proteins control their activity:
Three regulatory proteins control their activity: