A nuclear pore is a part of a large complex of proteins known as a nuclear pore complex that spans the nuclear envelope which is the double membrane surrounding the eukaryotic cell nucleus there are approximately 1 000 nuclear pore complexes npcs in the nuclear envelope of a vertebrate cell but it varies depending on cell type and the stage in the life cycle. 1986 the central rod domain is composed of four subhelical regions comprised. The nuclear lamins have the typical tripartite structure of intermediate filament if proteins consisting of a highly α helical central rod domain flanked by a short globular amino terminal head domain and a longer carboxy terminal tail domain parry et al.
Structure and assembly of the nuclear lamins. Lamins also known as nuclear lamins are fibrous proteins in type v intermediate filaments providing structural function and transcriptional regulation in the cell nucleus nuclear lamins interact with inner nuclear membrane proteins to form the nuclear lamina on the interior of the nuclear envelope lamins have elastic and mechanosensitive properties and can alter gene regulation in a. Lamins are type v intermediate filament proteins which have a short n terminal head domain a long α.
Lamin proteins are the main components of the lamina network and of nuclear architecture. Lamins can interact with one another with lamina associated proteins with nuclear scaffold proteins and with chromatin. It is composed of both peripheral and integral membrane proteins including lamins and lamina associated proteins.
The nuclear lamina is located between the inner nuclear membrane and the peripheral chromatin. These include the nuclear lamina proteins lamin a c and b type lamins 30 31 which are cleaved by caspase 6 12 as well as the lamin associated proteins lap2α and lap2β 30 37. B type lamins are constitutively expressed in all somatic cells and contain a stable c terminal farnesyl modification which mediates tight association with the inm.
The lamina is formed by type v intermediate filament proteins a and b type lamins which assemble to form a meshwork of 10 nm filaments underneath the inner nuclear membrane inm. The nuclear lamina is an essential component of metazoan cells. The increasing number of proteins that interact with lamins and the compound interactions between these proteins and chromatin associated proteins make the nuclear lamina a highly complex but also a very exciting structure.
215 pathogenic mutations in lmna have been identified as causes. 215 lamin a lmna is a principle component of the nuclear lamina that functions as a scaffolding molecule to assist in the organization of chromatin. The nuclear lamina is a dense fibrillar network of structural proteins that lines the inner nuclear membrane of eukaryotic cells.
The nuclear lamina is a dense 30 to 100 nm thick fibrillar network inside the nucleus of most cells it is composed of intermediate filaments and membrane associated proteins besides providing mechanical support the nuclear lamina regulates important cellular events such as dna replication and cell division additionally it participates in chromatin organization and it anchors the nuclear.
