Video Experimental Relacionado
Updated: Jul 6, 2026
10:49
Pre-clinical Evaluation of Tyrosine Kinase Inhibitors for Treatment of Acute Leukemia
Published on: September 19, 2013
La estructura cristalina y la función biológica del factor inhibidor de la leucemia: implicaciones para la unión al
R C Robinson1, L M Grey, D Staunton
1Department of Biochemistry, University of Oxford, England.
Cell
|July 1, 1994
Resumen
Los investigadores determinaron la estructura del factor inhibidor de la leucemia (LIF, por sus siglas en inglés) utilizando cristalografía de rayos X. Esto revela regiones clave involucradas en su interacción con los receptores, ofreciendo información sobre la función de las citoquinas.
Área de la Ciencia:
- Biología estructural Biología estructural.
- La bioquímica es la bioquímica.
- Biología molecular La biología molecular.
Sus antecedentes:
- El factor inhibidor de la leucemia (LIF, por sus siglas en inglés) es una citocina crucial en el sistema hematopoyético.
- Las estructuras de citocinas a menudo comparten patrones de plegado comunes, como el paquete de cuatro hélices alfa.
- Comprender la estructura del LIF es clave para descifrar sus funciones biológicas.
Objetivo del estudio:
- Determinar la estructura tridimensional de alta resolución del factor inhibidor de la leucemia murina (LIF).
- Para comparar la estructura de LIF con citoquinas relacionadas e identificar las características conservadas.
- Mapear las regiones funcionales involucradas en las interacciones de los receptores de LIF.
Principales métodos:
- Cristalografía de rayos X con una resolución de 2.0 A.
- Análisis de homología estructural con citoquinas hematopoyéticas relacionadas.
- Alineación de secuencias y mapeo en la estructura LIF.
- Análisis de las quimeras LIF humano-ratón para la función biológica y la especificidad del receptor.
Principales resultados:
- La estructura LIF murina adopta un pliegue de cuatro haces de hélice alfa, común en las citoquinas hematopoyéticas.
- LIF comparte la homología estructural más cercana con el factor estimulante de colonias de granulocitos y la hormona del crecimiento (GH).
- Se identificaron regiones superficiales conservadas mediante el mapeo de las secuencias de oncostatina M y del factor neurotrófico ciliar en la estructura LIF.
- Dos regiones específicas en la cuarta hélice y el bucle anterior estuvieron implicadas en la interacción del receptor de LIF.
Conclusiones:
- La estructura LIF determinada proporciona una base molecular detallada para su función.
- Las similitudes estructurales sugieren un origen evolutivo común y un mecanismo de acción para las citocinas relacionadas.
- Las regiones de interacción del receptor identificadas son críticas para comprender la actividad biológica y la especificidad de LIF.
- Puede ser necesario un nuevo modelo para la unión al receptor de GH, que incorpore características específicas de las interacciones LIF.
Videos de Conceptos Relacionados
02:40Ligand Binding Sites
Proteins are dynamic macromolecules that carry out a wide variety of essential processes; however, the activities of most proteins depend on their interactions with other molecules or ions, known as ligands.
Protein-ligand interactions are quite specific; even though numerous potential ligands surround a cellular protein at any given time, only a particular ligand can bind to that protein. Moreover, a ligand binds only to a dedicated area on the surface of the protein, known as the...
Protein-ligand interactions are quite specific; even though numerous potential ligands surround a cellular protein at any given time, only a particular ligand can bind to that protein. Moreover, a ligand binds only to a dedicated area on the surface of the protein, known as the...
01:15Receptor Downregulation in MVBs
Multivesicular bodies (MVBs) are mature endosomes that sort ubiquitinated proteins and then fuse with lysosomes to degrade the sorted proteins. Epidermal growth factor (EGF) and its receptor (EGFR) form a complex that can be internalized through endocytosis, sorted into an MVB, and later degraded.
The EGFR can initiate signaling pathways that lead to cell proliferation, migration, and differentiation. Overexpression of EGFR stimulates cells to proliferate. Excessive EGFR activation may...
The EGFR can initiate signaling pathways that lead to cell proliferation, migration, and differentiation. Overexpression of EGFR stimulates cells to proliferate. Excessive EGFR activation may...
01:26Receptor Tyrosine Kinases
Receptor tyrosine kinases or RTKs are membrane-bound receptors that phosphorylate specific tyrosine on protein substrates. RTKs regulate cellular growth, differentiation, survival, and migration. They contain an extracellular ligand binding domain, a transmembrane domain, and a cytosolic tail with intrinsic kinase activity. Several extracellular signaling molecules activate RTKs in one or more ways and relay the signal downstream. Ligands such as platelet-derived growth factor (PDGF) or...
01:17Intracellular Signaling Affects Focal Adhesions
Integrins act both as extracellular input receivers and as intracellular processing activators. As their name suggests, integrins are entirely integrated into the membrane structure. Their hydrophobic membrane-spanning regions interact with the phospholipid bilayer's hydrophobic region. These membrane receptors provide extracellular attachment sites for effectors like hormones and growth factors. They activate intracellular response cascades when their effectors are bound and active.
Some...
Some...
01:27Transducer Mechanism: Enzyme-Linked Receptors
Enzyme-linked receptors are cell-surface receptors acting as an enzyme or associating with an enzyme intracellularly. They make excellent drug targets. Drugs can bind to the extracellular ligand-binding domain or directly affect their enzymatic domain and alter their activity.
Major types that are helpful drug targets include:
Major types that are helpful drug targets include:
01:29The Two-State Receptor Model
The two-state receptor model explains a drug's interaction with receptors, such as G protein-coupled receptors and ligand-gated ion channels, to induce or inhibit a biological response. When no natural ligands are present, a receptor exists in an equilibrium of inactive (Ri) and active (Ra) conformations. The inactive form does not produce a response, while the active form generates a basal effect known as constitutive activity.
The binding affinity of a drug determines its interaction with one...
The binding affinity of a drug determines its interaction with one...