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ABCG5
ATP-binding cassette sub-family G member 5 is a protein that in humans is encoded by the ''ABCG5'' gene. Function The protein encoded by this gene is a member of the superfamily of ATP-binding cassette (ABC) transporters. ABC proteins transport various molecules across extra- and intra-cellular membranes. ABC genes are divided into seven distinct subfamilies (ABC1, MDR/TAP, MRP, ALD, OABP, GCN20, White). This protein is a member of the White subfamily. The protein encoded by this gene functions as a half-transporter to limit intestinal absorption and promote biliary excretion of sterols. It is expressed in a tissue-specific manner in the liver, colon, and intestine. This gene is tandemly arrayed on chromosome 2, in a head-to-head orientation with family member ABCG8. Mutations in this gene may contribute to sterol accumulation and atherosclerosis, and have been observed in patients with sitosterolemia Sitosterolemia is a rare autosomal recessively inherited lipid metabolic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ABCG8
ATP-binding cassette sub-family G member 8 is a protein that in humans is encoded by the ''ABCG8'' gene. The protein encoded by this gene is a member of the superfamily of ATP-binding cassette (ABC) transporters. ABC proteins transport various molecules across extra- and intra-cellular membranes. ABC genes are divided into seven distinct subfamilies (ABC1, MDR/TAP, MRP, ALD, OABP, GCN20, White). This protein is a member of the White subfamily. The protein encoded by this gene functions as a half-transporter to limit intestinal absorption and promote biliary excretion of sterols. It is expressed in a tissue-specific manner in the liver, colon, and intestine. This gene is tandemly arrayed on chromosome 2, in a head-to-head orientation with family member ABCG5. Mutations in this gene may contribute to sterol accumulation and atherosclerosis, and have been observed in patients with sitosterolemia. Interactive pathway map See also * ATP-binding cassette transporter The ATP synth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ABCG5 And ABCG8 Genes
ABCG5 and ABCG8 genes encode for two proteins sterolin-1 and -2, respectively. Sterolin-1 and –2 are two ‘half’ adenosine triphosphate binding (adenosine triphosphate, ATP) cassette (ABC) transporters which found to be indispensable for the regulation of sterol absorption and excretion. Mutations in either genes result in a lipid disorder, sitosterolemia. Locus of the genes The molecular mechanisms regulating the absorption of dietary sterols in the body are poorly understood, and as sitosterolemia is a rare autosomal recessively inherited lipid metabolic disorder characterized by hyperabsorption and decreased biliary excretion of dietary sterols, studies have focused on the molecular basis of sitosterolemia to shed light on important principles concerning intestinal sterol absorption as well as cholesterol secretion into bile. In 1998, sitosterolemia (STSL) locus has been mapped to the short arm of human chromosome 2 (2p21) after studying 10 well-characterized families ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sitosterolemia
Sitosterolemia is a rare autosomal recessively inherited lipid metabolic disorder. It is characterized by hyperabsorption and decreased biliary excretion of dietary sterols (including the plant phytosterol beta-sitosterol). Healthy persons absorb only about 5% of dietary plant sterols, but sitosterolemia patients absorb 15% to 60% of ingested sitosterol without excreting much into the bile. The phytosterol campesterol is more readily absorbed than sitosterol. Sitosterolemia patients develop hypercholesterolemia, tendon and tuberous xanthomas, premature development of atherosclerosis, and abnormal hematologic and liver function test results. Signs and symptoms Sitosterolemia may share several clinical characteristics with the well-characterized familial hypercholesterolemia (FH), such as the development of tendon xanthomas in the first 10 years of life and the development of premature atherosclerosis. However, in contrast to FH patients, sitosterolemia patients usually have nor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid residue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and 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 noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ATP-binding Cassette Transporter
The ATP-binding cassette transporters (ABC transporters) are a transport system superfamily that is one of the largest and possibly one of the oldest gene families. It is represented in all extant phyla, from prokaryotes to humans. ABC transporters belong to translocases. ABC transporters often consist of multiple subunits, one or two of which are transmembrane proteins and one or two of which are membrane-associated AAA ATPases. The ATPase subunits utilize the energy of adenosine triphosphate (ATP) binding and hydrolysis to provide the energy needed for the translocation of substrates across membranes, either for uptake or for export of the substrate. Most of the uptake systems also have an extracytoplasmic receptor, a solute binding protein. Some homologous ATPases function in non-transport-related processes such as translation of RNA and DNA repair. ABC transporters are considered to be an ABC superfamily based on the similarities of the sequence and organization of their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
