Citrin
mammalian protein found in Homo sapiens
Citrin, also known as solute carrier family 25, member 13 (citrin) or SLC25A13, is a protein which in humans is encoded by the SLC25A13 gene.
Citrin is associated with type II citrullinemia and neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD).
Function
Citrin (74 kDa) is a dimeric calcium-activated glutamate/aspartate carrier found in the mitochondrial membrane of mammals. Citrin is one of two isoforms of these mitochondrial calcium-activated glutamate/aspartate carriers found in humans and is predominately expressed in non-excitable tissues.
Upon binding calcium, citrin catalyzes the transport of glutamate and a proton into the mitochondrial matrix in exchange for aspartate transport to the cytosol. Upon being transported by citrin from the mitochondrial matrix to the cytosol, aspartate is converted into oxaloacetate, and then into malate, which is then transported back into the matrix by means of the malate-aspartate shuttle. Upon entering the mitochondrial matrix, malate is converted back into oxaloacetate to participate in the citric acid cycle. Citrin is also important because it supplies liver cells with aspartate that is used during the urea cycle and gluconeogenesis.
Structure
The citrin monomer peptide has a three-domain structure, consisting of an N-terminal domain, a carrier domain, and a C-terminal domain. The N-terminal domain contains eight EF-hand motifs and is responsible for the binding of a single calcium ion.
The public source identifies “Citrin” as mammalian protein found in Homo sapiens. This brief keeps that definition visible, then builds a research path around Citrin, mammalian and protein.
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This entry incorporates text from “Citrin” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.