Lamin

Lamin is a type of protein that is integral to the structural framework, or nuclear lamina, of the cell nucleus in eukaryotic cells. Lamins are classified as type V intermediate filaments and are primarily responsible for providing mechanical stability to the nucleus while also playing key roles in gene regulation, DNA replication, and cell division.

Structure[edit | edit source]

Lamins are composed of a central alpha-helical rod domain flanked by globular N-terminal (head) and C-terminal (tail) domains. The rod domain is involved in polymerization, forming parallel, coiled-coil dimers with other lamins. The head and tail domains are responsible for the interaction of lamins with chromatin and other proteins in the nuclear lamina.

Types[edit | edit source]

There are two major types of lamins: A-type and B-type, which are encoded by three different genes, LMNA, LMNB1, and LMNB2. A-type lamins include lamin A and lamin C, which are produced by alternative splicing of the LMNA gene. B-type lamins include lamin B1 and lamin B2, encoded by LMNB1 and LMNB2 genes respectively.

Function[edit | edit source]

Lamins play a crucial role in maintaining the mechanical stability and integrity of the nucleus. They are involved in various nuclear activities including DNA replication, transcription, and RNA splicing. Lamins also play a role in apoptosis, the programmed cell death, by regulating the activation of caspases, the enzymes that carry out apoptosis.

Clinical significance[edit | edit source]

Mutations in lamin genes, particularly LMNA, can lead to a range of diseases known as laminopathies, which include muscular dystrophies, cardiomyopathies, and premature aging syndromes. Research into these conditions is helping to elucidate the diverse functions of lamins in the cell.

File:Lamin.png

Structure of lamin A, B and C in the cell nucleus.