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nuclear membranes

Thursday 3 March 2005

The nuclear envelope is composed of the nuclear lamina, the nuclear pore complexes, and the nuclear membranes.

- The nuclear lamina is a discontinuous structure that occupies only a fraction of the nuclear periphery, and at some points, the inner nuclear membrane may interact directly with the chromatin.

- The nuclear membranes can be divided into 3 morphologically distinct but interconnected domains: the outer nuclear membrane, the inner nuclear membrane, and the nuclear pore membrane.

  • The inner nuclear membrane is adjacent to the nuclear lamina, a meshwork of intermediate filament proteins termed lamins.
  • Several integral proteins of the nuclear envelope inner membrane that may be associated with the lamina and the chromatin have been identified. The first was a protein called lamin B receptor (LBR) that binds in vitro to lamin B.

- To enter the nucleus a protein must be chaperoned by a transport factor through the nuclear pore complex or it must be small enough to pass through by diffusion.

References

- Lusk CP, Blobel G, King MC. Highway to the inner nuclear membrane: rules for the road. Nat Rev Mol Cell Biol. 2007 May;8(5):414-20. PMID: 17440484