PHOSPHATASES
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Phosphoinositides (PIs) are phosphorylated derivatives of phosphatidylinositol. They act as signaling molecules linked to essential cellular mechanisms in eukaryotic cells, such as cytoskeleton organization, mitosis, polarity, migration or invasion. PIs are phosphorylated and dephosphorylated by a large number of PI kinases and PI phosphatases acting at the 5-, 4- and 3- position of the inositol ring. PI 5-phosphatases i.e. OCRL, INPP5B, SHIP1/2, Synaptojanin 1/2, INPP5E, INPP5J, SKIP (INPP5K) are enzymes that dephosphorylate the 5-phosphate position of PIs. Several human genetic diseases such as the Lowe syndrome, some congenital muscular dystrophy and opsismodysplasia are due to mutations in PI phosphatases, resulting in loss-of-function. The PI phosphatases are also up or down regulated in several human cancers such as glioblastoma or breast cancer. Their cellular localization, that is dynamic and varies in response to stimuli, is an important issue to understand function. This is the case for two members of the PI 5-phosphatase SKIP and SHIP2. Both enzymes are in ruffles, plasma membranes, the endoplasmic reticulum, a situation that is unique for SKIP, and the nucleus. Following localization, PI 5-phosphatases act on specific cellular pools of PIs, which in turn interact with target proteins. Nuclear PIs have emerged as regulators of genome functions in different area of cell signaling. They often localize to nuclear speckles, as do several PI metabolizing kinases and phosphatases. We asked whether SKIP and SHIP2 could have an impact on nuclear PI(4,5)P2. In two glioblastoma cell models, lowering SKIP expression had an impact on nuclear PI(4,5)P2. In a model of SHIP2 deletion in MCF-7 cells, no change in nuclear PI(4,5)P2 was observed. Finally, we present evidence of an anti-tumoral role of SKIP in vivo, in xenografts using as model U87shSKIP cells.
- MeSH
- buněčné jádro enzymologie genetika MeSH
- endoplazmatické retikulum enzymologie genetika patologie MeSH
- fosfatasy genetika metabolismus MeSH
- fosfatidylinositol-3,4,5-trisfosfát-5-fosfatasy genetika metabolismus MeSH
- glioblastom enzymologie genetika patologie MeSH
- lidé MeSH
- MFC-7 buňky MeSH
- myši inbrední NOD MeSH
- myši SCID MeSH
- myši MeSH
- nádorové proteiny genetika metabolismus MeSH
- nádory prsu enzymologie genetika patologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Activation of mast cells and basophils is accompanied by the production of reactive oxygen and nitrogen species that regulate diverse signaling pathways leading to the release of inflammatory mediators and production of a variety of cytokines. Although the functional pathways of reactive oxygen and nitrogen species in vivo are not completely understood, some novel metabolic pathways can be envisioned based on recent findings that protein tyrosine phosphatases can be regulated by reversible oxidation. In this review, we describe major sources and targets of reactive oxide and nitrogen species in mast cells and basophils. Direct and indirect regulations of class I and II Cys-based protein tyrosine phosphatases (LMW-PTP, PTEN, PTP-PEST, SHP-2, PTP1B, PTPalpha, PTPepsilon, DEP-1, TC45, SHP-1, HePTP and LAR) are discussed. The combined data highlight the role of redox-regulated protein tyrosine phosphatases as targets in the development of new ways of therapeutic intervention in allergies and inflammatory diseases.
- MeSH
- bazofily enzymologie metabolismus MeSH
- cystein metabolismus MeSH
- financování organizované MeSH
- lidé MeSH
- mastocyty enzymologie metabolismus MeSH
- reaktivní formy dusíku metabolismus MeSH
- reaktivní formy kyslíku metabolismus MeSH
- tyrosinfosfatasy klasifikace metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- přehledy MeSH
