Difference between revisions of "Phosphatase Subfamily VSP"
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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). | + | 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 family 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]) | + | 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>. |
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| + | TPTE is predicted to be catalytically inactive, and TPTE2 has been shown to have phosphoinositide 3-phosphatase activity <cite>Walker</cite>. | ||
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| + | The Ciona homolog, Ci-VSP encodes a functional voltage-sensing domain expressed in sperm, and transduces membrane depolarization into alteration of phosphoinositide levels <cite>Murata</cite>. Ci-VSP has phosphatase activity against PI(3,4,5)P3 and PI(4,5)P2 <cite>Iwasaki</cite>. 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 <cite> Ogasawara </cite>. | ||
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===References=== | ===References=== | ||
<biblio> | <biblio> | ||
| + | Guipponi pmid=11810268 | ||
| + | Ogasawara pmid=21172457 | ||
| + | Walker pmid=11716755 | ||
| + | Iwasaki pmid=18524949 | ||
| + | Murata pmid=15902207 | ||
</biblio> | </biblio> | ||
Revision as of 03:42, 29 December 2014
Phosphatase Classification: Superfamily CC1: Family PTEN: Subfamily VSP
This page is a stub - more information to follow.
The Voltage Sensitive Phosphatase (VSP) members consist of a voltage sensor consisting of four transmembrane segments, in addition to phosphatase domain and C2 domain. It has two members in human, TPTE and TPTE2 (TPIP), but TPTE is a pseudophosphatase. The subfamily is conserved in holozoa but absent from nematodes and most arthropods. It usually has a single copy in each species, and the two human copies appear to be a primate duplication.
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 family 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). 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 |
