Video Experimental Relacionado
Updated: May 3, 2026
12:13
Single-Molecule Imaging of Nuclear Transport
Published on: June 10, 2010
12.7K
La exportación de importina alfa desde el núcleo está mediada por un factor de transporte nuclear específico
U Kutay1, F R Bischoff, S Kostka
1Zentrum für Molekulare Biologie der Universität Heidelberg, Federal Republic of Germany.
Cell
|October 10, 1997
Resumen
La proteína CAS facilita el regreso de la importina alfa al citoplasma después de la importación nuclear, asegurando que las proteínas nucleares permanezcan en el núcleo. Este mecanismo de reexportación es crucial para la regulación del transporte nuclear.
Área de la Ciencia:
- Biología celular Biología celular.
- Biología Molecular Biología Molecular
- El transporte de proteínas en transporte.
Sus antecedentes:
- Las proteínas de la secuencia de localización nuclear (NLS) se transportan al núcleo a través del heterodímero importina alfa/beta.
- La importina beta facilita la translocación a través del complejo de poros nucleares, y la unión de RanGTP en el núcleo desplaza a la importina alfa.
Objetivo del estudio:
- Investigar el mecanismo de la reexportación de importina alfa desde el núcleo al citoplasma.
- Para identificar la proteína responsable de mediar el regreso de la importina alfa al citoplasma.
Principales métodos:
- Investigó la interacción entre la proteína CAS, la importina alfa y el RanGTP.
- Se analizó el papel de RanBP1 y RanGAP1 en la liberación de importina alfa del complejo.
Principales resultados:
- La proteína CAS media la reexportación de importina alfa, y se une a la importina alfa en presencia de RanGTP.
- Se forma un complejo ternario de importina alfa/CAS/RanGTP.
- RanBP1 y RanGAP1 facilitan la liberación de importina alfa en el citoplasma.
Conclusiones:
- La proteína CAS es esencial para la reexportación citoplasmática de la importina alfa.
- La unión preferencial del CAS a la importina alfa libre de NLS explica la retención del sustrato en el núcleo.
Videos de Conceptos Relacionados
02:31Nuclear Export of mRNA
7.1K
Before mRNAs are exported to the cytoplasm, it is crucial to check each mRNA for structural and functional integrity. Eukaryotic cells use several different mechanisms, collectively known as mRNA surveillance, to look for irregularities in mRNAs. Irregular or aberrant mRNA are rapidly degraded by various enzymes. If a defective mRNA escapes the surveillance, it would be translated into a protein which would either be non-functional or not function properly. One of the primary irregularities in...
7.1K
01:34Nuclear Protein Sorting
4.8K
Nuclear protein sorting is the selective trafficking of histones, polymerases, gene regulatory proteins into the nucleus and exporting RNAs and ribosomes to the cytosol. It is a tightly controlled process that regulates gene expression within a cell.
Proteins targeted to the nucleus carry nuclear localization signals or NLS recognized by import receptors in the cytosol. Similarly, proteins with nuclear export signals are recognized by export receptors. Import and export receptors are...
Proteins targeted to the nucleus carry nuclear localization signals or NLS recognized by import receptors in the cytosol. Similarly, proteins with nuclear export signals are recognized by export receptors. Import and export receptors are...
4.8K
01:46Nuclear Localization Signals and Import
6.2K
Proteins targeted to the nucleus carry short stretches of amino acid sequences called the nuclear localization signal or NLS. Classical nuclear localization signals are of two types: monopartite and bipartite NLS. Monopartite classical NLS (cNLS) consists of a single cluster of 4-8 amino acids. Bipartite cNLS consists of two clusters of 2-3 amino acids and a 9-12 residue long proline-rich linker bridging the two clusters. Signal clusters are rich in positively charged amino acids such as...
6.2K
01:42Nuclear Export
3.7K
The nucleus restricts several proteins within and allows others to pass. The restricted proteins possess a nuclear retention sequence or NRS, anchoring them to the nuclear lamins and preventing their transport to the cytosol. The non-restricted proteins, after their synthesis, are transported to their site of action, such as the cytosol or other organelles, with the help of nuclear export signals or NES.
NES are of three types- the canonical 10-residue long leucine-rich signal and other...
NES are of three types- the canonical 10-residue long leucine-rich signal and other...
3.7K
01:42Directionality of Nuclear Transport
3.9K
Ras-related nuclear protein or Ran is a small G protein that cycles between its GTP and GDP bound states. Ran specific regulators, a Ran GTPase Activating Protein or RanGAP present in the cytosol and a Ran guanine nucleotide exchange factor or RanGEF present inside the nucleus regulate GTP/GDP exchange. A high concentration of GTP inside the cells, in addition to this asymmetric distribution of Ran-specific regulators, leads to a higher RanGTP concentration inside the nucleus. This...
3.9K
01:45Regulation of Nuclear Protein Sorting
2.5K
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...
2.5K