Lamina

Lamina, also known as cell nucleus lamina, is a dense, fibrillar compound contained in eukaryotic cell nuclei, which is located directly under the nuclear envelope and is about 30nm to 100nm thick. The nuclear lamina is connected to the inner membrane of the nuclear envelope. It consists of intermediate filaments of type V (laminin) and lamina-binding membrane proteins.

Laminins are specific for animals. Plants or eukaryotic unicellular organisms do not have a laminin. It is assumed that laminin proteins are involved in nuclear stability, chromatin structure and gene expression. Lamin-binding membrane proteins are either integral or peripheral. The most important are LAP1 and LAP2 (for lamin associated protein), emerin, lamin B receptor (LBR), otefin, MAN1 and the Nesprine. Due to their position within the inner membrane or via their contact points, they cause the lamina to adhere to the nuclear envelope. In addition to a supporting function, the lamina plays a role in processes such as the regulation of DNA replication and cell division as well as in chromatin organisation.