Video Experimental Relacionado
Updated: May 29, 2026
12:15
In Vitro Polymerization of F-actin on Early Endosomes
Published on: August 28, 2017
La clasificación dependiente de ubiquitina en la vía multivesicular del cuerpo requiere la función de un complejo de
D J Katzmann1, M Babst, S D Emr
1Division of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, CA 92093, USA.
Cell
|August 21, 2001
Resumen
La ubiquitinación señala la clasificación de la carga en la vía del cuerpo multivesicular (MVB). Un complejo ESCRT-I conservado reconoce la carga ubiquitinada, esencial para la formación de vesículas MVB y la regulación a la baja del receptor.
Área de la Ciencia:
- Biología celular Biología celular.
- Biología Molecular Biología Molecular
- La bioquímica es la bioquímica.
Sus antecedentes:
- La vía del cuerpo multivesicular (MVB, por sus siglas en inglés) es crucial para la administración de hidrolasa lisosomal y la regulación a la baja de los receptores de la superficie celular.
- Los receptores de superficie celular activados están dirigidos a la degradación dentro del lisosoma a través de la vía MVB.
Objetivo del estudio:
- Para investigar el papel de la ubiquitinación en la clasificación de la carga en la vía MVB.
- Identificar y caracterizar los complejos de proteínas involucrados en el reconocimiento de la carga ubiquitinada para la clasificación MVB.
Principales métodos:
- Demostración de la ubiquitinación como una señal de clasificación para la vía MVB.
- Caracterización del complejo ESCRT-I (Vps23, Vps28, Vps37) y su papel en el reconocimiento de carga MVB.
- Análisis del dominio similar a UBC en Vps23 para su papel en el reconocimiento de la ubiquitina.
Principales resultados:
- La ubiquitinación se confirmó como una señal para la clasificación en la vía MVB.
- El complejo ESCRT-I fue identificado como un actor clave en el reconocimiento de la carga MVB ubiquitinada.
- La función ESCRT-I es esencial para la formación de vesículas MVB y la posterior clasificación de la carga.
Conclusiones:
- ESCRT-I es un componente conservado de la maquinaria de clasificación endosómica en levaduras y células de mamíferos.
- El estudio establece un vínculo entre la modificación de la ubiquitina y la clasificación de proteínas / regulación a la baja de los receptores en la vía MVB.
- El dominio similar a Vps23 UBC es crítico para mediar el reconocimiento de la carga ubiquitinada por parte de ESCRT-I.
Videos de Conceptos Relacionados
01:28The Early Endosome: Endocytosis of Transferrin
Essential proteins such as insulin or low-density lipoprotein (LDL) and micronutrients such as iron enter a eukaryotic cell through receptor-mediated endocytosis. Subsequently, the early endosomes fuse with the vesicles containing such receptor-ligand complexes and play a vital role in sorting the incoming ligands and receptors. While the ligands are either degraded inside the vesicle or released into the cytosol, their receptors are returned to the plasma membrane for further rounds of...
01:38Intralumenal Vesicles and Multivesicular Bodies
Intraluminal vesicles (ILVs) are small vesicles 50-80 nm in diameter formed during the maturation of early endosomes. A specialized endosome containing numerous ILVs is called a multivesicular body (MVB). ILVs contain internalized molecules such as antigens, nucleic acids, proteins, and metabolites. Some of these molecules are released from the MVBs inside exosomes and are transported to other cells. Other MVBs contain molecules that are retained in the ILVs and are later degraded within the...
00:58Recycling Endosomes and Transcytosis
The recycling endosome, also known as the endosomal recycling compartment (ERC), is a part of the slow-recycling process of the endocytic pathway. Molecules internalized through receptor-mediated endocytosis are either degraded in the lysosomes or are recycled to the plasma membrane through the fast- or slow-recycling route.
The recycling endosome is not a single organelle but an extensively tubulated network of recycling pathways. It functions in storing molecules or transporting them across...
The recycling endosome is not a single organelle but an extensively tubulated network of recycling pathways. It functions in storing molecules or transporting them across...
01:39Mitochondrial Protein Sorting
Mitochondria are double-membrane organelles of the eukaryotes involved in cellular metabolism, signaling, ATP synthesis, and programmed cell death. Each of these processes requires specific proteins and enzymes that must be correctly sorted to the right mitochondrial subcompartment for the proper functioning of the organelle.
Most of these mitochondrial proteins are encoded by the nucleus and imported to the mitochondria as unfolded or loosely folded precursors. Mitochondrial precursors...
Most of these mitochondrial proteins are encoded by the nucleus and imported to the mitochondria as unfolded or loosely folded precursors. Mitochondrial precursors...
01:45ER Retrieval Pathway
In the secretory pathway, vesicles transport proteins from one cellular compartment to another in forward transport to deliver the protein to its correct location. Occasionally, misfolded proteins and incorrect proteins escape their original compartments, and a retrieval pathway is used to return the escaped proteins to their original compartment.
The ER uses many checkpoints to prevent the entry of incorrectly folded or a resident protein as cargo onto a transport vesicle. These mechanisms...
The ER uses many checkpoints to prevent the entry of incorrectly folded or a resident protein as cargo onto a transport vesicle. These mechanisms...
01:32Export of Misfolded Proteins out of the ER
After folding, the ER assesses the quality of secretory and membrane proteins. The correctly folded proteins are cleared by the calnexin cycle for transport to their final destination, while misfolded proteins are held back in the ER lumen. The ER chaperones attempt to unfold and refold the misfolded proteins but sometimes fail to achieve the correct native conformation. Such terminally misfolded proteins are then exported to the cytosol by ER-associated degradation or ERAD pathway for...