関連する実験動画
Updated: Aug 7, 2026
12:13
Single-Molecule Imaging of Nuclear Transport
Published on: June 10, 2010
核タンパク質の輸入における2つのインポートサブユニットの異なる機能
Nature
|September 21, 1995
まとめ
核タンパク質のインポートには,核局所化信号 (NLS) にインポートイン-αとインポートイン-βの結合が含まれます. この複合体はインポルチンベータ経由でドックし,核孔を通って転位し,解体し,核に荷物を放出します.
科学分野:
- 細胞生物学 細胞生物学
- 分子生物学は分子生物学である.
- バイオケミストリー バイオケミストリー
背景:
- 核タンパク質の輸入は,細胞機能に不可欠です.
- このプロセスは,核の局所化信号 (NLS),エネルギー,およびインポートリン-α,インポートリン-β,およびRan.のような溶性因子を必要とします.
- インポートイン-アルファはNLSを認識し,酵母SRP1p.に関連しています.
研究 の 目的:
- 核孔標的複合転位のメカニズムを解明する.
- 核輸入におけるインポートリンアルファとインポートリンベータの役割を調査する.
- 核転位中のインポートリンベータの運命を決定する.
主な方法:
- 輸入複合体の形成を研究するための拘束力のある測定法.
- タンパク質の転位を追跡するための核輸入アッセイ.
- 免疫電子顕微鏡で,核孔のタンパク質の局所化を視覚化します.
主要な成果:
- インポルチン-α/インポルチン-β複合体は,インポルチン基板をサイトゾールに結合する.
- 核毛孔標的化複合体は,最初にインポートリン-β.を介して核毛孔にドッキングします.
- エネルギーに依存し,Ran媒介による転位は,核内の輸入基板とインポートリン-αの蓄積につながり,インポートリン-βは核封筒に局所する.
結論:
- 核孔を標的とする複合体は,核孔を通って単一の実体として転位する可能性が高い.
- インポルチンベータはドッキングを容易にし,潜在的に転移を誘導し,核包膜に蓄積する.
- 複合体は核プラズマ側で分解され,核に負荷とインポートリンアルファを放出します.
関連する概念動画
01:34Nuclear Protein Sorting
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...
01:46Nuclear Localization Signals and Import
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...
01:42Nuclear Export
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...
01:42Directionality of Nuclear Transport
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...
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...
01:34Protein Transport into the Inner Mitochondrial Membrane
Nuclear encoded mitochondrial precursors are imported to the inner membrane in a multistep process involving two separate translocons, TIM22 and TIM23. TIM23 is a cation-selective pore that remains closed by the N terminal segment of the protein. Negative charges on the TIM23 act as a receptor for the incoming precursor, pulling the positively charged matrix-targeting sequence for peptide insertion and translocation.
Transport of mitochondrial precursors across the TIM23 channel is driven by...
Transport of mitochondrial precursors across the TIM23 channel is driven by...