LBR

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.

Pathology

 germline mutations of LBR gene in autosomal recessive Greenberg syndrome (hydrops-ectopic calcification- moth eaten skeletal dysplasia or HEM/Greenberg skeletal dysplasia)

• causing 3 beta-hydroxysterol delta 14-reductase deficiency (12618959)

See also

 nuclear envelope

• nuclear lamina
  • lamins

• nuclear pore complexes
• nuclear membranes