Video Experimental Relacionado
Updated: Jun 11, 2026
10:15
Isolation of Ribosome Bound Nascent Polypeptides in vitro to Identify Translational Pause Sites Along mRNA
Published on: July 6, 2012
Una proteína del retículo endoplasmático involucrada temprano en la translocación de polipéptidos
D Görlich1, E Hartmann, S Prehn
1Max-Delbrück Center for Molecular Medicine, Berlin-Buch, Germany.
Nature
|May 7, 1992
Resumen
Los investigadores identificaron una proteína clave en la membrana del retículo endoplasmático esencial para la translocación de proteínas secretoras. Esta abundante glicoproteína ayuda a las cadenas nacientes durante su movimiento temprano, facilitando el transporte de proteínas.
Área de la Ciencia:
- Biología celular Biología celular.
- Biología molecular La biología molecular.
- La translocación de proteínas por translocación.
Sus antecedentes:
- Las proteínas secretoras deben cruzar la membrana del retículo endoplasmático.
- La maquinaria molecular que media esta translocación no se entiende completamente.
Objetivo del estudio:
- Identificar los componentes del retículo endoplasmático de los mamíferos involucrados en la translocación de proteínas secretoras.
- Caracterice la función de una glicoproteína de membrana recién identificada en este proceso.
Principales métodos:
- Métodos combinados de reticulación y reconstitución.
- Utilizó cadenas de polipéptidos nacientes y proteoliposomas.
Principales resultados:
- Se identificó una glicoproteína de membrana multispanning y abundante.
- Esta glicoproteína está cerca de las cadenas nacientes al principio de la translocación.
- La proteína identificada es estimulante o necesaria para la translocación de proteínas secretoras en proteoliposomas reconstituidos.
Conclusiones:
- Una glicoproteína de membrana específica juega un papel crucial en la translocación de proteínas del retículo endoplasmático.
- Este hallazgo avanza en nuestra comprensión de los mecanismos moleculares que gobiernan el transporte de proteínas a través de las membranas de los orgánulos.
Videos de Conceptos Relacionados
02:11Proteins: From Genes to Degradation
Within a biological system, the DNA encodes the RNA, and the nucleotide sequence in the RNA further defines the amino acid sequence in the protein. This is referred to as “The Central Dogma of Molecular Biology” - a term coined by Francis Crick. Central dogma is a firm principle in biology that defines the flow of genetic information within any life form. The two fundamental steps in central dogma are - transcription and translation.
Transcription is the synthesis of RNA molecules by RNA...
Transcription is the synthesis of RNA molecules by RNA...
01:20Cotranslational Protein Translocation
Translocation of proteins across membranes is an ancient process that occurs even in bacteria and archaebacteria. In fact, the components of the translocation machinery are still conserved between prokaryotes and eukaryotes.
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
01:29Protein Folding Quality Check in the RER
ER is the primary site for the maturation and folding of soluble and transmembrane secretory proteins. The calnexin cycle is a specific chaperone system that folds and assesses the confirmation of N-glycosylated proteins before they can exit the ER lumen. The primary players of this quality check pipeline are the lectins, ER-resident chaperones, and a glucosyl transferase enzyme. In case the calnexin system in the lumen fails to salvage a misfolded protein, it is transported to the cytoplasm...
01:27Post-translational Translocation of Proteins to the RER
A sizable fraction of proteins destined for ER are first synthesized in the cell cytosol and then transported across the ER membrane–a process called post-translational translocation. Similar to cotranslationally translocated proteins, these proteins also use the Sec translocon complex to enter the ER lumen.
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
01:28Protein Translocation Machinery on the ER Membrane
The translocon complex situated on the ER membrane is the main gateway for the protein secretory pathway. It facilitates the transport of nascent peptides into the ER lumen and their insertion into the ER membrane.
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the translocon complex.
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the translocon complex.
01:26Bacterial Protein Maturation
Bacterial protein maturation is a tightly regulated process that ensures newly synthesized polypeptides achieve correct functional conformations. This maturation involves a series of modifications, folding events, and quality control steps, often assisted by specialized chaperone proteins.N-Terminal ModificationsThe maturation of bacterial polypeptides begins cotranslationally as the polypeptide exits the ribosome. The first amino acid, N-formylmethionine (fMet), is typically modified at the...