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nuclear lamina

Sunday 13 July 2003

The nuclear lamina is a proteinaceous layer apposed to the inner nuclear membrane. It is composed of a family of polypeptides, the lamins, highly conserved in evolution. During mitosis, the lamina meshwork is reversibly disassembled in parallel with phosphorylation of the lamins.

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.

Struture

The peripheral nuclear lamina is located near the nuclear inner membrane and consists of lamin filaments and integral membrane proteins, including the lamin B receptor and various isoforms of lamina-associated polypeptides (LAP) 1 and 2.

Several nuclear membrane proteins also interact with chromatin proteins BAF and Hp1. Lamins in the nuclear interior associate with at least one soluble (non-membrane-bound) LAP2 isoform named LAP2alpha.

The internal lamins, together with Tpr-based filaments that connect to nuclear pore complexes, are proposed to be major structural elements of the internal nuclear matrix.

References

- Mounkes LC, Stewart CL. Aging and nuclear organization: lamins and progeria. Curr Opin Cell Biol. 2004 Jun;16(3):322-7. PMID: 15145358

- Worman HJ, Courvalin JC. The nuclear lamina and inherited disease. Trends Cell Biol. 2002 Dec;12(12):591-8. PMID: 12495848

- Vlcek S, Dechat T, Foisner R. Nuclear envelope and nuclear matrix: interactions and dynamics. Cell Mol Life Sci. 2001 Nov;58(12-13):1758-65. PMID: 11767745