Video Experimental Relacionado

Updated: Nov 6, 2025

Isolation of Labile Multi-protein Complexes by in vivo Controlled Cellular Cross-Linking and Immuno-magnetic Affinity Chromatography

Isolation of Labile Multi-protein Complexes by in vivo Controlled Cellular Cross-Linking and Immuno-magnetic Affinity Chromatography

Published on: March 9, 2010

Estructuras del mediador humano y del complejo de preiniciación ligado al mediador

Xizi Chen¹, Xiaotong Yin¹, Jiabei Li¹

¹Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Radiation Oncology, and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China.

Science (New York, N.Y.)

|May 7, 2021

Resumen

El factor de transcripción IID (TFIID) orquesta el ensamblaje del complejo de preiniciación. El estudio revela cómo las interacciones TFIID-Mediator estabilizan el dominio C-terminal de la ARN polimerasa II para la fosforilación, crucial para el inicio de la transcripción.

Área de la Ciencia:

Biología molecular
Biología estructural
Regulación genética

Sus antecedentes:

El factor de transcripción IID (TFIID) es esencial para la iniciación de la transcripción de la ARN polimerasa II (Pol II).
El complejo Mediator estimula la transcripción y regula la fosforilación del dominio C-terminal Pol II (CTD) por CDK7.

Objetivo del estudio:

Determinar las estructuras de los complejos PIC-Mediator humanos y basados en TFIID.
Elucidar los mecanismos estructurales de la reorganización del mediador y la fosforilación de la CTD durante la iniciación de la transcripción.

Principales métodos:

Microscopía criolectrónica de resolución casi atómica
Determinación estructural de los complejos Mediator y TFIID-Mediator en conformaciones distintas

Principales resultados:

El ensamblaje PIC-Mediador induce la reorganización del Mediador, formando un sándwich de Cabeza y Medio.
Esta estructura estabiliza los segmentos de CTD y facilita la fosforilación mediada por CDK7 a través de un mecanismo de apertura de CTD.
La arquitectura TFIID modula la organización del Mediador y la estabilización del TFIIH.

Conclusiones:

El TFIID desempeña un papel fundamental en la orquestación de las reuniones del PIC-Mediador.
Se propone un mecanismo de apertura de CTD que implique la reorganización del mediador para una fosforilación eficiente de CTD.
Estos hallazgos proporcionan información sobre la regulación de la iniciación de la transcripción.

Más Videos Relacionados

Combining Chemical Cross-linking and Mass Spectrometry of Intact Protein Complexes to Study the Architecture of Multi-subunit Protein Assemblies

Combining Chemical Cross-linking and Mass Spectrometry of Intact Protein Complexes to Study the Architecture of Multi-subunit Protein Assemblies

Published on: November 28, 2017

Author Spotlight: Evaluating Biophysical Assays for Characterizing PROTACS Ternary Complexes

Author Spotlight: Evaluating Biophysical Assays for Characterizing PROTACS Ternary Complexes

Published on: January 12, 2024

Videos de Conceptos Relacionados

Microtubule Formation

Microtubule Formation

Microtubules are dynamic structures that undergo continuous assembly and disassembly. They originate from specialized multi-protein complexes known as microtubule organizing centers or MTOCs. Within the MTOC, the point of origin of the microtubule is known as the minus end, while the end radiating outward is the plus end. Microtubules serve two primary functions — the organization of spindle complexes to separate sister chromatids during mitotic or meiotic cell division and the formation...

Mitochondrial Precursor Proteins

Mitochondrial Precursor Proteins

Mitochondrial precursors are partially unfolded or loosely folded polypeptide chains. Newly synthesized precursors are inhibited from spontaneously folding into their native conformation by the cytosolic chaperones, heat shock proteins 70 (Hsp70), and mitochondrial import stimulation factors (MSFs). Precursors bound to MSFs are guided to the TOM70-TOM37 receptors, while precursors bound to Hsp70 chaperones are targetted to TOM20-TOM22 receptor complexes.
Most of the mitochondrial...

Assembly of Signaling Complexes

Assembly of Signaling Complexes

Multiprotein signaling complexes are formed in a dynamic process involving protein-protein interactions at the cytoplasmic domain of transmembrane receptors or enzymatic and non-enzymatic proteins associated with the receptor. These complexes ensure the activation and propagation of intracellular signals that regulate cell functions.
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...

Transcription Initiation

Transcription Initiation

Initiation is the first step of transcription in eukaryotes. Prokaryotic RNA Polymerase (RNAP) can bind to the template DNA and start transcribing. On the other hand, transcription in eukaryotes requires additional proteins, called transcription factors, to first bind to the promoter region in the DNA template. This binding helps recruit the specific RNAP that can assemble on the DNA and start transcription.
The promoters and enhancers and their accessory proteins allow tight regulation of...

Formation of Intermediate Filaments

Formation of Intermediate Filaments

Intermediate filaments are cytoskeletal proteins with higher tensile strength and flexibility than microfilaments and microtubules. Unlike the other two cytoskeletal proteins, intermediate filament formation lacks the enzymatic activity to hydrolyze nucleotides like ATP and GTP to generate energy for polymerization. Therefore, the formation of intermediate filaments is multistep self-assembly. The involvement of any accessory proteins in intermediate filament formation has not yet been...

The Structure of Intermediate Filaments

The Structure of Intermediate Filaments

The intermediate filaments are one of three widely studied cytoskeletal filaments. They are so named as their diameter (10 nm) is in between that of microfilaments (7 nm) and the microtubules (25 nm). These filaments are highly stable and can remain intact when exposed to high salt concentrations and detergents. These filaments are responsible for providing stability and mechanical support to the cells. They also help in cell adhesion and maintaining tissue integrity.
Intermediate...