1. Monica Wilson Signal-Mediated Transport Through Nuclear Pore Complex

2. Outline What is a nuclear pore complex? What is a nuclear pore complex? Structure of a nuclear pore complex. Structure of a nuclear pore complex. Nuclear Export Signals Nuclear Export Signals Nuclear Localization Signals Nuclear Localization Signals

3. What Is a Nuclear Pore Complex? In all eucaryotic cells the nuclear envelope is perforated by many pores. In all eucaryotic cells the nuclear envelope is perforated by many pores. Each pore forms an elaborate structure called Nuclear Pore Complex (NPC). Each pore forms an elaborate structure called Nuclear Pore Complex (NPC). Large, multiprotein structure in the nuclear envelope through which ions and small molecules can diffuse. Large, multiprotein structure in the nuclear envelope through which ions and small molecules can diffuse. NPC mediates the active transport of ribonucleoproteins and large proteins between the nucleus and cytoplasm. NPC mediates the active transport of ribonucleoproteins and large proteins between the nucleus and cytoplasm.

4. Structure of a Nuclear Pore Complex Extensive electron microscopy studies, predominantly of nucleoplasmin, an abundant nuclear protein in Xenopus oocytes, are responsible for the structure of NPC. NPC is about 30 times larger than a ribosome. Made up of 50-100 different proteins.

5. Nuclear-export Signals (NES) Nuclear-export signal (NES) stimulates a particular protein’s active transport through nuclear pores. Nuclear-export signal (NES) stimulates a particular protein’s active transport through nuclear pores. Transport from nucleus to the cytosol. Transport from nucleus to the cytosol. The mechanism of export of proteins is best understood for those containing a leucine-rich NES. The mechanism of export of proteins is best understood for those containing a leucine-rich NES.

6. Nuclear-localization signals (NLS) All proteins actively imported through nuclear pore complexes contain a nuclear-localization signal. All proteins actively imported through nuclear pore complexes contain a nuclear-localization signal. Transport from cytoplasm to nucleus. Transport from cytoplasm to nucleus. Mechanism for import of “cargo” proteins is best understood for those containing a basic NLS. Mechanism for import of “cargo” proteins is best understood for those containing a basic NLS.

7. Summary Nuclear Pore Complex is a large multiprotein, which ions and small molecules can diffuse and mediates the active transport of macromolecules. Nuclear Pore Complex is a large multiprotein, which ions and small molecules can diffuse and mediates the active transport of macromolecules. The discovery of the structure of NPC was done with an electron micrograph, studying Xenopus oocytes. The discovery of the structure of NPC was done with an electron micrograph, studying Xenopus oocytes. The transport of proteins from nucleus to cytosol requires a nuclear export signal along with various other proteins and enzymes. The transport of proteins from cytosol to nucleus requires nuclear localization signal along with various other proteins and enzymes.

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