Major component of the nuclear lamina, a fibrous layer on the nucleoplasmic side of the inner nuclear membrane. Provides a framework for the nuclear envelope and probably also interacts with chromatin. Essential to maintain the shape and integrity of the nucleus, and for DNA replication. Involved in spatial organization of nuclear pore complexes. It is not a target for ced-3 during apoptosis, suggesting that lamin cleavage is not essential for apoptosis in C.elegans.