Video Experimental Relacionado
Updated: Jul 16, 2026
11:27
Analysis of SCAP N-glycosylation and Trafficking in Human Cells
Published on: November 8, 2016
OSBP es una proteína de andamio regulada por el colesterol en el control de la activación de ERK 1/2
Ping-Yuan Wang1, Jian Weng, Richard G W Anderson
1Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039, USA.
Science (New York, N.Y.)
|March 5, 2005
Resumen
El colesterol que se une a la proteína de unión al oxicósterol (OSBP) forma un complejo fosfatasa que regula la vía de señalización ERK. Este complejo se desmonta cuando los niveles de colesterol bajan, aumentando la señalización.
Área de la Ciencia:
- Biología celular Biología celular.
- La bioquímica es la bioquímica.
- La señalización molecular.
Sus antecedentes:
- La proteína de unión al oxisterol (OSBP, por sus siglas en inglés) es una proteína clave de unión al esterol.
- Las proteínas de la familia OSBP están involucradas en el metabolismo de los lípidos, el transporte de las vesículas y la transducción de señales.
Objetivo del estudio:
- Para investigar el papel de OSBP en la regulación de la vía de señalización de la quinasas reguladas por la señal extracelular (ERK).
- Para dilucidar el mecanismo por el cual el colesterol que se une a OSBP afecta la señalización celular.
Principales métodos:
- Pruebas bioquímicas para caracterizar la formación de oligómeros de la OSBP.
- Análisis de las interacciones proteína-proteína dentro del complejo OSBP.
- Medición de los niveles de ERK fosforilados (pERK) bajo diferentes condiciones de colesterol.
Principales resultados:
- El OSBP citosólico forma un complejo oligomérico de ~440 kDa con las fosfatasas de tirosina, PP2A y colesterol.
- Este oligómero de OSBP exhibe una actividad dual de fosfatasa hacia pERK.
- El desmontaje del oligómero al agotamiento del colesterol o la exposición al oxisterol conduce a un aumento de los niveles de pERK.
- El aumento de los niveles de oligómeros de OSBP confiere resistencia a los efectos de agotamiento del colesterol en pERK.
Conclusiones:
- La unión del colesterol a la OSBP fuera de las membranas es crucial para regular el ensamblaje del complejo fosfatasa.
- El complejo OSBP-colesterol actúa como una proteína de andamiaje que controla la señalización de la vía ERK.
- Este mecanismo pone de relieve un nuevo papel para el colesterol en la modulación de las vías de transducción de señales intracelulares.
Más Videos Relacionados
Videos de Conceptos Relacionados
01:45Regulation of Nuclear Protein Sorting
Nuclear protein sorting regulates nucleus composition and gene expression, crucial for determining the fate of a eukaryotic cell. Hence, the entry and exit of molecules across the nuclear envelope is a tightly controlled process. Nuclear protein sorting can be inhibited by one of the following ways: 1) masking cargo signal sequences, 2) modifying the nuclear receptor's affinity for cargo, 3) controlling the nuclear pore size, 4) retaining the cargo during its transit to the cytosol or the...
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...
01:37The Unfolded Protein Response
The ER is the hub of protein synthesis in a cell. It has robust systems to quality control protein folding and also for degradation of terminally misfolded proteins. Under normal conditions, a small proportion of misfolded proteins that cannot be salvaged need to be transported to the cytoplasm by the ER-associated degradation or ERAD pathways. However, if the ERAD cannot handle the misfolded proteins, the cell activates the unfolded protein response or UPR to adjust the protein folding...
01:22Amplifying Signals via Enzymatic Cascade
When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze the...
01:07MAPK Signaling Cascades
Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...
01:20The JAK-STAT Signaling Pathway
Several cytokine receptors have tightly bound Janus kinase or JAK proteins attached at their cytosolic tail. Small signaling molecules such as cytokines, growth hormones, or prolactins bind to the cytokine receptors and initiate their dimerization. The dimerization brings the cytosolic JAKs together that trans-phosphorylate and activates each other. The activated JAKs now phosphorylate cytosolic tails of the cytokine receptors, which serve as binding sites for adaptor proteins such as SH2...