Difference between revisions of "Phosphatase Subfamily VSP"
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[[Phosphatase classification|Phosphatase Classification]]: [[Phosphatase_Superfamily_CC1|Superfamily CC1]]: [[Phosphatase_Family_PTEN|Family PTEN]]: [[Phosphatase_Subfamily_VSP|Subfamily VSP]] | [[Phosphatase classification|Phosphatase Classification]]: [[Phosphatase_Superfamily_CC1|Superfamily CC1]]: [[Phosphatase_Family_PTEN|Family PTEN]]: [[Phosphatase_Subfamily_VSP|Subfamily VSP]] | ||
| − | + | VSP is a transmembrane protein with a lipid phosphatase that is activated by a voltage sensor and controls activity of ion channels. | |
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===Evolution=== | ===Evolution=== | ||
| − | VSPs are holozoan-specific and lost in both nematodes and insects. There are two human genes, TPTE (PTEN2) and TPTE2 (TPIP). TPTE is a primate specific duplicate of the TPTE2 locus (found in human and Gorilla, but not in chimp) There are 7 | + | VSPs are holozoan-specific and lost in both nematodes and insects. There are two human genes, TPTE (PTEN2) and TPTE2 (TPIP). TPTE is a primate-specific duplicate of the TPTE2 locus (found in human and Gorilla, but not in chimp) There are 7 subfamily pseudogenes, some of which are expressed in testis, and at least one of which is conserved in orangutan. |
===Domain Structure=== | ===Domain Structure=== | ||
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===Functions=== | ===Functions=== | ||
| − | Both human genes are testis specific (GTEx: [http://www.gtexportal.org/home/gene/TPTE TPTE], [http://www.gtexportal.org/home/gene/TPTE TPTE2]). The single mouse gene is localized to the Golgi apparatus <cite>Guipponi</cite>, while TPTE has been reported to be on the plasma membrane, while splice variants of TPTE2 are found in the ER or in the cytoplasm <cite>Walker</cite>. | + | Both human genes are testis specific (GTEx: [http://www.gtexportal.org/home/gene/TPTE TPTE], [http://www.gtexportal.org/home/gene/TPTE TPTE2]), though some expression in brain and stomach has been reported. The single mouse gene is localized to the Golgi apparatus <cite>Guipponi</cite>, while TPTE has been reported to be on the plasma membrane, while splice variants of TPTE2 are found in the ER or in the cytoplasm <cite>Walker</cite>. |
TPTE is predicted to be catalytically inactive, and TPTE2 has been shown to have phosphoinositide 3-phosphatase activity <cite>Walker</cite>. | TPTE is predicted to be catalytically inactive, and TPTE2 has been shown to have phosphoinositide 3-phosphatase activity <cite>Walker</cite>. | ||
Revision as of 03:46, 29 December 2014
Phosphatase Classification: Superfamily CC1: Family PTEN: Subfamily VSP
VSP is a transmembrane protein with a lipid phosphatase that is activated by a voltage sensor and controls activity of ion channels.
Evolution
VSPs are holozoan-specific and lost in both nematodes and insects. There are two human genes, TPTE (PTEN2) and TPTE2 (TPIP). TPTE is a primate-specific duplicate of the TPTE2 locus (found in human and Gorilla, but not in chimp) There are 7 subfamily pseudogenes, some of which are expressed in testis, and at least one of which is conserved in orangutan.
Domain Structure
VSPs consist of an N-terminal voltage sensor with four transmembrane regions, followed by a phosphatase domain and a PTEN_C2 domain
Functions
Both human genes are testis specific (GTEx: TPTE, TPTE2), though some expression in brain and stomach has been reported. The single mouse gene is localized to the Golgi apparatus [1], while TPTE has been reported to be on the plasma membrane, while splice variants of TPTE2 are found in the ER or in the cytoplasm [2].
TPTE is predicted to be catalytically inactive, and TPTE2 has been shown to have phosphoinositide 3-phosphatase activity [2].
The Ciona homolog, Ci-VSP encodes a functional voltage-sensing domain expressed in sperm, and transduces membrane depolarization into alteration of phosphoinositide levels [3]. Ci-VSP has phosphatase activity against PI(3,4,5)P3 and PI(4,5)P2 [4]. The PI(4,5)P2 activity is not seen in PTEN, and change in levels of PI(4,5)P2 affects the activity of a family of potassium channels. CI-VSP has also been seen expressed in stomach and blood cells [5].
References
- Guipponi M, Tapparel C, Jousson O, Scamuffa N, Mas C, Rossier C, Hutter P, Meda P, Lyle R, Reymond A, and Antonarakis SE. The murine orthologue of the Golgi-localized TPTE protein provides clues to the evolutionary history of the human TPTE gene family. Hum Genet. 2001 Dec;109(6):569-75. DOI:10.1007/s004390100607 |
