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TMEM38B
Trimeric intracellular cation-selective channel B (TRIC-B) is a monovalent cation channel in the ER membrane encoded by the ''transmembrane protein 38B (TMEM38B)'' gene. It is one of two known TRIC proteins, the other being TRIC-A. Function TRIC-B is permeable to both Na+ and K+ but not divalent cations like Ca2+. The channel exhibits marked voltage-dependence, becoming more open when the cytosol is more positively charged than the ER lumen. There at least four major sub-conductance states (with 80%, 60%, 46% and 30% of the conductance of the fully-opened channel). ''TMEM38B''-knockout mice exhibit reduced IP3-receptor-mediated Ca2+ release. As such, K+ flux into the ER through TRIC-B is thought to support IP3-induced efflux of Ca2+ ions through IP3-gated Ca2+ channels in the ER membrane. Clinical significance Null mutations in ''TMEM38B'' reduce the levels of functional TRIC-B in heterozygotes and abolish expression of functional TRIC-B in homozygotes. Such mutations a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteogenesis Imperfecta
Osteogenesis imperfecta (; OI), colloquially known as brittle bone disease, is a group of genetic disorders that all result in bones that break easily. The range of symptoms—on the skeleton as well as on the body's other organs—may be mild to severe. Symptoms found in various types of OI include whites of the eye (sclerae) that are blue instead, short stature, loose joints, hearing loss, breathing problems and problems with the teeth (dentinogenesis imperfecta). Potentially life-threatening complications, all of which become more common in more severe OI, include: tearing ( dissection) of the major arteries, such as the aorta; pulmonary valve insufficiency secondary to distortion of the ribcage; and basilar invagination. The underlying mechanism is usually a problem with connective tissue due to a lack of, or poorly formed, type I collagen. In more than 90% of cases, OI occurs due to mutations in the ''COL1A1'' or ''COL1A2'' genes. These mutations may be inherited ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trimeric Intracellular Cation-selective Channel
The trimeric intracellular cation-selective channels or TRIC proteins are a group of homo-trimeric cation channel proteins of ~300 residues in the ER membrane. There are two known TRIC proteins, TRIC-A and TRIC-B. Channel function TRICs are permeable to both Na+ and K+ but not divalent cations like Ca2+. They exhibit marked voltage-dependence, becoming more open when the cytosol is more positively charged than the ER lumen. TRIC-A TRIC-A is predominantly expressed in excitable tissues including brain and skeletal muscle. TRIC-A activity is thought to support RyR1-mediated efflux of Ca2+ ions from the sarcoplasmic reticulum into the cytosol. TRIC-B K+ flux into the ER through TRIC-B is thought to support IP3-induced efflux of Ca2+ ions through IP3-gated Ca2+ channels in the ER membrane. Clinical significance TRIC-A has been implicated in the regulation of arterial blood pressure through regulating the excitability of vascular smooth muscle cells. Several single-nucl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TMEM38A
Trimeric intracellular cation-selective channel A (TRIC-A) is a monovalent cation channel in the SR and nuclear membranes of skeletal muscle cells, encoded by the ''transmembrane protein 38A (TMEM38A)'' gene. It is one of two known TRIC proteins, the other being TRIC-B. Structure TRIC-A is a 33kDa transmembrane protein, expressed predominantly in excitable tissues including skeletal muscle and brain. Its N-terminal region is located in the SR lumen or within the nucleus while its C-terminal region projects into the cytoplasm. ''In situ'', TRIC-A forms homo-trimers, producing its ''"bullet-shaped"'' three-dimensional structure (seVenturi et al. (2012), Figure 1for a three-dimensional rendering of TRIC-A). Function TRIC-A is permeable to both Na+ and K+ but not divalent cations like Ca2+. The channel exhibits marked voltage-dependence, becoming more open when the cytosol is more positively charged than the ER lumen. ''TMEM38A''-knockout mice exhibit reduced Ryanodine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene Knockout
A gene knockout (abbreviation: KO) is a genetic technique in which one of an organism's genes is made inoperative ("knocked out" of the organism). However, KO can also refer to the gene that is knocked out or the organism that carries the gene knockout. Knockout organisms or simply knockouts are used to study gene function, usually by investigating the effect of gene loss. Researchers draw inferences from the difference between the knockout organism and normal individuals. The KO technique is essentially the opposite of a gene knock-in. Knocking out two genes simultaneously in an organism is known as a double knockout (DKO). Similarly the terms triple knockout (TKO) and quadruple knockouts (QKO) are used to describe three or four knocked out genes, respectively. However, one needs to distinguish between heterozygous and homozygous KOs. In the former, only one of two gene copies (alleles) is knocked out, in the latter both are knocked out. Methods Knockouts are accomplished throu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dominance (genetics)
In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and the second recessive. This state of having two different variants of the same gene on each chromosome is originally caused by a mutation in one of the genes, either new (''de novo'') or inherited. The terms autosomal dominant or autosomal recessive are used to describe gene variants on non-sex chromosomes ( autosomes) and their associated traits, while those on sex chromosomes (allosomes) are termed X-linked dominant, X-linked recessive or Y-linked; these have an inheritance and presentation pattern that depends on the sex of both the parent and the child (see Sex linkage). Since there is only one copy of the Y chromosome, Y-linked traits cannot be dominant or recessive. Additionally, there are other forms of dominance such as incomplete d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mutation
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mitosis, or meiosis or other types of damage to DNA (such as pyrimidine dimers caused by exposure to ultraviolet radiation), which then may undergo error-prone repair (especially microhomology-mediated end joining), cause an error during other forms of repair, or cause an error during replication (translesion synthesis). Mutations may also result from insertion or deletion of segments of DNA due to mobile genetic elements. Mutations may or may not produce detectable changes in the observable characteristics (phenotype) of an organism. Mutations play a part in both normal and abnormal biological processes including: evolution, cancer, and the development of the immune system, including junctional diversity. Mutation is the ultimate source o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zygosity
Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Most eukaryotes have two matching sets of chromosomes; that is, they are diploid. Diploid organisms have the same loci on each of their two sets of homologous chromosomes except that the sequences at these loci may differ between the two chromosomes in a matching pair and that a few chromosomes may be mismatched as part of a chromosomal sex-determination system. If both alleles of a diploid organism are the same, the organism is homozygous at that locus. If they are different, the organism is heterozygous at that locus. If one allele is missing, it is hemizygous, and, if both alleles are missing, it is nullizygous. The DNA sequence of a gene often varies from one individual to another. These gene variants are called alleles. While some gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Null Allele
A null allele is a nonfunctional allele (a variant of a gene) caused by a genetic mutation. Such mutations can cause a complete lack of production of the associated gene product or a product that does not function properly; in either case, the allele may be considered nonfunctional. A null allele cannot be distinguished from deletion of the entire locus solely from phenotypic observation. A mutant allele that produces no RNA transcript is called an RNA null (shown by Northern blotting or by DNA sequencing of a deletion allele), and one that produces no protein is called a protein null (shown by Western blotting). A genetic null or amorphic allele has the same phenotype when homozygous as when heterozygous with a deficiency that disrupts the locus in question. A genetic null allele may be both a protein null and an RNA null, but may also express normal levels of a gene product that is nonfunctional due to mutation. Null alleles can have lethal effects depending on the importance o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inositol Trisphosphate Receptor
Inositol trisphosphate receptor (InsP3R) is a membrane glycoprotein complex acting as a Ca2+ channel activated by inositol trisphosphate (InsP3). InsP3R is very diverse among organisms, and is necessary for the control of cellular and physiological processes including cell division, cell proliferation, apoptosis, fertilization, development, behavior, learning and memory. Inositol triphosphate receptor represents a dominant second messenger leading to the release of Ca2+ from intracellular store sites. There is strong evidence suggesting that the InsP3R plays an important role in the conversion of external stimuli to intracellular Ca2+ signals characterized by complex patterns relative to both space and time, such as Ca2+ waves and oscillations. Discovery The InsP3 receptor was first purified from rat cerebellum by neuroscientists Surachai Supattapone and Solomon Snyder at Johns Hopkins University School of Medicine. The cDNA of the InsP3 receptor was first cloned in the la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mouse
A mouse ( : mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus''). Mice are also popular as pets. In some places, certain kinds of field mice are locally common. They are known to invade homes for food and shelter. Mice are typically distinguished from rats by their size. Generally, when a muroid rodent is discovered, its common name includes the term ''mouse'' if it is smaller, or ''rat'' if it is larger. The common terms ''rat'' and ''mouse'' are not taxonomically specific. Typical mice are classified in the genus '' Mus'', but the term ''mouse'' is not confined to members of ''Mus'' and can also apply to species from other genera such as the deer mouse, ''Peromyscus''. Domestic mice sold as pets often differ substantially in size from the common house mouse. This is attributable to breeding a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cation
An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convention. The net charge of an ion is not zero because its total number of electrons is unequal to its total number of protons. A cation is a positively charged ion with fewer electrons than protons while an anion is a negatively charged ion with more electrons than protons. Opposite electric charges are pulled towards one another by electrostatic force, so cations and anions attract each other and readily form ionic compounds. Ions consisting of only a single atom are termed atomic or monatomic ions, while two or more atoms form molecular ions or polyatomic ions. In the case of physical ionization in a fluid (gas or liquid), "ion pairs" are created by spontaneous molecule collisions, where each generated pair consists of a free electron and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lumen (anatomy)
In biology, a lumen (plural lumina) is the inside space of a tubular structure, such as an artery or intestine. It comes . It can refer to: *The interior of a vessel, such as the central space in an artery, vein or capillary through which blood flows. *The interior of the gastrointestinal tract *The pathways of the bronchi in the lungs *The interior of renal tubules and urinary collecting ducts *The pathways of the female genital tract, starting with a single pathway of the vagina, splitting up in two lumina in the uterus, both of which continue through the Fallopian tubes In cell biology, a lumen is a membrane-defined space that is found inside several organelles, cellular components, or structures: *thylakoid, endoplasmic reticulum, Golgi apparatus, lysosome, mitochondrion, or microtubule Transluminal procedures ''Transluminal procedures'' are procedures occurring through lumina, including: *Natural orifice transluminal endoscopic surgery in the lumina of, for example, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
