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Piga (other)
Phosphatidylinositol N-acetylglucosaminyltransferase subunit A (PIG-A, or phosphatidylinositol glycan, class A) is the catalytic subunit of the phosphatidylinositol N-acetylglucosaminyltransferase enzyme, which in humans is encoded by the ''PIGA'' gene. This gene encodes a protein required for synthesis of N-acetylglucosaminyl phosphatidylinositol (GlcNAc-PI), the first intermediate in the biosynthetic pathway of GPI anchor. The GPI anchor is a glycolipid found on many blood cells and serves to anchor proteins to the cell surface. Paroxysmal nocturnal hemoglobinuria, an acquired hematologic disorder, has been shown to result from somatic mutations in this gene. Alternate splice variants have been characterized. Multiple Congenital Anomalies-Hypotonia-Seizures syndrome type 2 (MCAHS2), also known as PIGA-CDG or PIGA deficiency, has been shown to result from germline mutation A germline mutation, or germinal mutation, is any detectable variation within germ cells (cells that, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphatidylinositol N-acetylglucosaminyltransferase
In enzymology, a phosphatidylinositol N-acetylglucosaminyltransferase () is an enzyme that catalyzes the chemical reaction :UDP-''N''-acetylglucosamine + phosphatidylinositol \rightleftharpoons UDP + ''N''-acetyl-D-glucosaminylphosphatidylinositol Thus, the two substrates of this enzyme are UDP-''N''-acetylglucosamine and phosphatidylinositol, whereas its two products are UDP and ''N''-acetyl-D-glucosaminylphosphatidylinositol. The mammalian enzyme is composed of at least six subunits ( PIG-A, PIG-H, PIG-C, PIG-P, PIG-Y, and GPI1). PIG-A is the catalytic subunit. This enzyme belongs to the family of glycosyltransferases, to be specific the hexosyltransferases. The systematic name of this enzyme class is UDP-N-acetyl-D-glucosamine:1-phosphatidyl-1D-myo-inositol 6-(N-acetyl-alpha-D-glucosaminyl)transferase. Other names in common use include UDP-N-acetyl-D-glucosamine:phosphatidylinositol, N-acetyl-D-glucosaminyltransferase, uridine diphosphoacetylglucosamine, and alpha1, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and non-coding genes. During gene expression (the synthesis of Gene product, RNA or protein from a gene), DNA is first transcription (biology), copied into RNA. RNA can be non-coding RNA, directly functional or be the intermediate protein biosynthesis, template for the synthesis of a protein. The transmission of genes to an organism's offspring, is the basis of the inheritance of phenotypic traits from one generation to the next. These genes make up different DNA sequences, together called a genotype, that is specific to every given individual, within the gene pool of the population (biology), population of a given species. The genotype, along with environmental and developmental factors, ultimately determines the phenotype ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GPI Anchor
Glycosylphosphatidylinositol () or glycophosphatidylinositol (GPI) is a phosphoglyceride that can be attached to the C-terminus of a protein during posttranslational modification. The resulting GPI-anchored proteins play key roles in a wide variety of biological processes. GPI is composed of a phosphatidylinositol group linked through a carbohydrate-containing linker (glucosamine and mannose glycosidically bound to the inositol residue) and via an ethanolamine phosphate (EtNP) bridge to the C-terminal amino acid of a mature protein. The two fatty acids within the hydrophobic phosphatidyl-inositol group anchor the protein to the cell membrane. Synthesis Glycosylated (GPI-anchored) proteins contain a signal sequence, thus directing them to the endoplasmic reticulum (ER). The protein is co-translationally inserted in the ER membrane via a translocon and is attached to the ER membrane by its hydrophobic C terminus; the majority of the protein extends into the ER lumen. The hydro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paroxysmal Nocturnal Hemoglobinuria
Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired, life-threatening disease of the blood characterized by destruction of red blood cells by the complement system, a part of the body's innate immune system. This destructive process occurs due to deficiency of the red blood cell surface protein DAF, which normally inhibits such immune reactions. Since the complement cascade attacks the red blood cells within the blood vessels of the circulatory system, the red blood cell destruction (hemolysis) is considered an ''intravascular'' hemolytic anemia. There is ongoing research into other key features of the disease, such as the high incidence of venous blood clot formation. Research suggests that PNH thrombosis (a blood clot) is caused by both the absence of GPI-anchored complement regulatory proteins (CD55 and CD59) on PNH platelets and the excessive consumption of nitric oxide (NO). PNH is the only hemolytic anemia caused by an ''acquired'' (rather than inherited) intr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germline Mutation
A germline mutation, or germinal mutation, is any detectable variation within germ cells (cells that, when fully developed, become sperm and Egg cell, ova). Mutations in these cells are the only mutations that can be passed on to offspring, when either a mutated sperm or oocyte come together to form a zygote. After this fertilization event occurs, germ cells divide rapidly to produce all of the cells in the body, causing this mutation to be present in every Somatic (biology), somatic and germline cell in the offspring; this is also known as a constitutional mutation. Germline mutation is distinct from somatic mutation. Germline mutations can be caused by a variety of endogenous (internal) and exogenous (external) factors, and can occur throughout zygote development. A mutation that arises only in germ cells can result in offspring with a genetic condition that is not present in either parent; this is because the mutation is not present in the rest of the parents' body, only the ger ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
