LBR | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Aliases | LBR , DHCR14B, LMN2R, PHA, TDRD18, lamin B receptor, PHASK, C14SR | ||||||||||||||||||||||||||||||||||||||||||||||||||
External IDs | OMIM: 600024 MGI: 2138281 HomoloGene: 2455 GeneCards: LBR | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Lamin-B receptor is a protein, and in humans, it is encoded by the LBR gene. [5] [6] [7]
The protein encoded by this gene belongs to the ERG4/ERG24 family. It localizes to the inner membrane of the nuclear envelope and anchors the lamina and the heterochromatin to the membrane. It may mediate the interaction between chromatin and lamin B. Mutations of this gene has been associated with autosomal recessive HEM/Greenberg skeletal dysplasia. Alternative splicing occurs at this locus and two transcript variants encoding the same protein have been identified. [7]
There is evidence tying it to Greenberg dysplasia [8] and Pelger-Huet anomaly. [9]
Lamin B receptor has been shown to interact with CBX3 [10] and CBX5. [10] LBR also interacts with long non-coding RNA XIST in mouse cells and potentially assist the spreading XIST across X chromosome in differentiating female embryonic stem cells, [11] but it might be redundant for correct XCI in vivo. [12]
The cell nucleus is a membrane-bound organelle found in eukaryotic cells. Eukaryotic cells usually have a single nucleus, but a few cell types, such as mammalian red blood cells, have no nuclei, and a few others including osteoclasts have many. The main structures making up the nucleus are the nuclear envelope, a double membrane that encloses the entire organelle and isolates its contents from the cellular cytoplasm; and the nuclear matrix, a network within the nucleus that adds mechanical support.
The nucleoplasm, also known as karyoplasm, is the type of protoplasm that makes up the cell nucleus, the most prominent organelle of the eukaryotic cell. It is enclosed by the nuclear envelope, also known as the nuclear membrane. The nucleoplasm resembles the cytoplasm of a eukaryotic cell in that it is a gel-like substance found within a membrane, although the nucleoplasm only fills out the space in the nucleus and has its own unique functions. The nucleoplasm suspends structures within the nucleus that are not membrane-bound and is responsible for maintaining the shape of the nucleus. The structures suspended in the nucleoplasm include chromosomes, various proteins, nuclear bodies, the nucleolus, nucleoporins, nucleotides, and nuclear speckles.
Telophase is the final stage in both meiosis and mitosis in a eukaryotic cell. During telophase, the effects of prophase and prometaphase are reversed. As chromosomes reach the cell poles, a nuclear envelope is re-assembled around each set of chromatids, the nucleoli reappear, and chromosomes begin to decondense back into the expanded chromatin that is present during interphase. The mitotic spindle is disassembled and remaining spindle microtubules are depolymerized. Telophase accounts for approximately 2% of the cell cycle's duration.
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 feedback response to mechanical cues. Lamins are present in all animals but are not found in microorganisms, plants or fungi. Lamin proteins are involved in the disassembling and reforming of the nuclear envelope during mitosis, the positioning of nuclear pores, and programmed cell death. Mutations in lamin genes can result in several genetic laminopathies, which may be life-threatening.
The nuclear lamina is a dense fibrillar network inside the nucleus of eukaryote 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 pore complexes embedded in the nuclear envelope.
Lamina-associated polypeptide 2 (LAP2), isoforms beta/gamma is a protein that in humans is encoded by the TMPO gene. LAP2 is an inner nuclear membrane (INM) protein.
Laminopathies are a group of rare genetic disorders caused by mutations in genes encoding proteins of the nuclear lamina. They are included in the more generic term nuclear envelopathies that was coined in 2000 for diseases associated with defects of the nuclear envelope. Since the first reports of laminopathies in the late 1990s, increased research efforts have started to uncover the vital role of nuclear envelope proteins in cell and tissue integrity in animals.
Pre-lamin A/C or lamin A/C is a protein that in humans is encoded by the LMNA gene. Lamin A/C belongs to the lamin family of proteins.
LEM domain-containing protein 3 (LEMD3), also known as MAN1, is an integral protein in the inner nuclear membrane (INM) of the nuclear envelope. It is encoded by the LEMD3 gene and was first identified after it was isolated from the serum of a patient with a collagen vascular disease.
Chromobox protein homolog 3 is a protein that is encoded by the CBX3 gene in humans.
Anti-glycoprotein-210 antibodies are directed at gp210 and are found within primary biliary cirrhosis (PBC) patients in high frequency. AGPA recognize the cytoplasmic-oriented carboxyl terminus (tail) of the protein. While AGPA is found as a prognostic marker in only a minority of PBC patients, those that did had higher mortality and were predicted a poor outcome. In addition, patients that responded to ursodeoxycholic acid (UDCA) therapy and, therefore, had AGPA reductions failed to develop end-stage liver disease relative to untreated cohort with anti-gp210 Ab. PBC patients with potentially destructive AGPA have increased expression of Nup210 in the bile duct, a potential immune tolerance-escaping factor.
Protein kinase C beta type is an enzyme that in humans is encoded by the PRKCB gene.
High-mobility group protein HMG-I/HMG-Y is a protein that in humans is encoded by the HMGA1 gene.
Endothelin receptor type A, also known as ETA, is a human G protein-coupled receptor.
Chromodomain-helicase-DNA-binding protein 8 is an enzyme that in humans is encoded by the CHD8 gene.
Chromobox protein homolog 5 is a protein that in humans is encoded by the CBX5 gene. It is a highly conserved, non-histone protein part of the heterochromatin family. The protein itself is more commonly called HP1α. Heterochromatin protein-1 (HP1) has an N-terminal domain that acts on methylated lysines residues leading to epigenetic repression. The C-terminal of this protein has a chromo shadow-domain (CSD) that is responsible for homodimerizing, as well as interacting with a variety of chromatin-associated, non-histone proteins.
Torsin-1A-interacting protein 1 is a protein that in humans is encoded by the TOR1AIP1 gene. More commonly known as lamina associated polypeptide 1 (LAP1), it is a type II integral membrane protein that resides in the inner nuclear membrane. The luminal domain of LAP1 interacts with Torsin A and is necessary for the ATPase activity of Torsin A. LAP1 plays a critical role in skeletal and heart muscle. Mutations in TOR1AIP1 have been linked to muscular dystrophy and cardiomyopathy. It's deletion from mouse hepatocytes leads to defected very-low density lipoprotein secretion and causes non-alcoholic fatty liver disease and non-alcoholic steatohepatitis
Nuclear prelamin A recognition factor, also known as NARF, is a protein which in humans is encoded by the NARF gene.
Lamin-B1 is a protein that in humans is encoded by the LMNB1 gene.
Inner nuclear membrane proteins are membrane proteins that are embedded in or associated with the inner membrane of the nuclear envelope. There are about 60 INM proteins, most of which are poorly characterized with respect to structure and function. Among the few well-characterized INM proteins are lamin B receptor (LBR), lamina-associated polypeptide 1 (LAP1), lamina-associated polypeptide-2 (LAP2), emerin and MAN1.