A lattice of fibrils which covers the entire inner surface of the nuclear envelope and interlinks nuclear pores (NUCLEAR PORE).

The fibrous, electron-dense layer lying on the nucleoplasmic side of the inner membrane of a cell nucleus, composed of lamin filaments. The polypeptides of the lamina are thought to be concerned in the dissolution of the nuclear envelope and its re-formation during mitosis. The lamina is composed of lamin A and lamin C filaments cross-linked into an orthogonal lattice, which is attached via lamin B to the inner nuclear membrane through interactions with a lamin B receptor, an IFAP, in the membrane.

The nuclear lamina is a proteinaceous filamentous meshwork of lamin proteins interacting with integral proteins of the inner nuclear membrane, including emerin, and is thought to play a role in nuclear stability, chromatin structure, and gene expression. Lamins are highly conserved in evolution and members of the intermediate filament protein family. Mammalian lamins are classified into two major types, A and B, with two subspecies of each: lamins A and C for the A type and B1 and B2 for the B type. Lamins A and C arise from one gene by alternative splicing. Pre-lamin A contains a carboxyl CAAX box that can be modified by farnesylation. During mitosis, the lamina meshwork is reversibly disassembled in parallel with phosphorylation of the lamins.