The nuclear lamina is a dense, ~ 30 to 100 nanometers thick, fibrillar network composed of intermediate filaments made of lamin that lines the inner surface of the nuclear envelope in animal cells. At the onset of mitosis, a certain cyclin-dependent kinase complex (Cdk1 and cyclin B in mammals) phosphorylates the lamins, causing them to undergo a conformational change that triggers the disassembly of the nuclear envelope. After the chromosomes have migrated to each pole, the lamins are dephosphorylated, allowing them to begin to reform the nuclear lamina. Initially the lamina reassembles directly on the outer surface of the condensed chromosomes by binding to proteins which associate the condensed DNA, thus excluding all cytoplasmic proteins from the newly forming intranuclear space. The lamins also bind to lamin receptor proteins embedded in the membrane of the endoplasmic reticulum (the ER membrane is continuous with the nuclear envelope). This allows the nuclear envelope to reform around each of the chromosomes. As the chromosomes unwind, their individual coatings of ER membrane merge with one another to form a single nuclear envelope supported by the nuclear lamina. Even during interphase the lamins maintain interactions with DNA binding proteins or DNA itself, especially with heterochromatin which tends to cluster at the surface of the nuclear lamina. // Intermediate filaments (IFs) are important structural proteins which are located both in the cytoplasm and the nucleus. ... A lamin is a fibrous protein that gives the cell nucleus its shape. ... The nuclear envelope (also known as the perinuclear envelope, nuclear membrane, nucleolemma or karyotheca) is the double membrane of the nucleus that encloses genetic material in eukaryotic cells. ... Mitosis divides genetic information during cell division. ... A cyclin-dependent kinase complex (abbreviated cdkc, also called cyclin-CDK) is a protein complex formed by the association of cyclin with cyclin-dependent kinase. ... A scheme of a condensed (metaphase) chromosome. ... The endoplasmic reticulum or ER is an organelle found in all eukaryotic cells that is an interconnected network of tubules, vesicles and cisternae that is responsible for several specialized functions: Protein translation, folding, and transport of proteins to be used in the cell membrane (e. ... Interphase is a phase of the cell cycle. ... For differently-colored eyes, see Heterochromia. ...
Defects in the genes encoding for nuclear lamin (such as LMNA and LMNB1) have been implicated in a variety of diseases such as: Normal nuclear lamina (a and b) and mutant nuclear lamina (c and d) from a patient with HGPS, visualized by immunofluorescence - note the irregular and bumpy shape of the laminopathic nuclei[1] Laminopathies are a group of rare genetic disorders caused by mutations in genes encoding proteins of the nuclear...
Emery-Dreifuss muscular dystrophy - A muscle wasting disease
Restrictive dermopathy - A disease associated with extremely tight skin and other severe neonatal abnormalities
Emery-Dreifuss muscular dystrophy is a condition that chiefly affects muscles used for movement (skeletal muscles) and heart (cardiac) muscle. ... The term Progeria narrowly refers to Hutchinson-Gilford Progeria syndrome, but the term is also used more generally to describe any of the so-called accelerated aging diseases. The word progeria is derived from the Greek for prematurely old. Because the accelerated aging diseases display different aspects of aging, but...
Further reading
Goldman et al., "Nuclear lamins: building blocks of nuclear architecture", Genes and Development 16:543-547, 2002. A good introductory article.
The nuclear envelope is a specialized domain of the endoplasmic reticulum that forms the boundary of the nucleus in eukaryotes.
We are using a combination of biochemical, structural and functional approaches to investigate the mechanisms involved in the nuclear import of protein and the role of the lamina in the nuclear organization.
These and other data indicate that the nuclearlamina engages in a complex set of cooperative, developmentally regulated interactions with chromatin that involves both lamins and integral membrane proteins, which could be important for stabilizing or modifying patterns of gene expression in cells.
Feeds |
Contact