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The SH2-containing inositol polyphosphate 5-phosphatase, SHIP-2, binds filamin and regulates submembraneous actin
SHIP-2 is a phosphoinositidylinositol 3,4,5 trisphosphate (PtdIns[3,4,5]P(3)) 5-phosphatase that contains an NH(2)-terminal SH2 domain, a central 5-phosphatase domain, and a COOH-terminal proline-rich domain. SHIP-2 negatively regulates insulin signaling. In unstimulated cells, SHIP-2 localized in a...
Autores principales: | , , , , , , , , |
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Formato: | Texto |
Lenguaje: | English |
Publicado: |
The Rockefeller University Press
2001
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2150887/ https://www.ncbi.nlm.nih.gov/pubmed/11739414 http://dx.doi.org/10.1083/jcb.200104005 |
Sumario: | SHIP-2 is a phosphoinositidylinositol 3,4,5 trisphosphate (PtdIns[3,4,5]P(3)) 5-phosphatase that contains an NH(2)-terminal SH2 domain, a central 5-phosphatase domain, and a COOH-terminal proline-rich domain. SHIP-2 negatively regulates insulin signaling. In unstimulated cells, SHIP-2 localized in a perinuclear cytosolic distribution and at the leading edge of the cell. Endogenous and recombinant SHIP-2 localized to membrane ruffles, which were mediated by the COOH-terminal proline–rich domain. To identify proteins that bind to the SHIP-2 proline–rich domain, yeast two-hybrid screening was performed, which isolated actin-binding protein filamin C. In addition, both filamin A and B specifically interacted with SHIP-2 in this assay. SHIP-2 coimmunoprecipitated with filamin from COS-7 cells, and association between these species did not change after epidermal growth factor stimulation. SHIP-2 colocalized with filamin at Z-lines and the sarcolemma in striated muscle sections and at membrane ruffles in COS-7 cells, although the membrane ruffling response was reduced in cells overexpressing SHIP-2. SHIP-2 membrane ruffle localization was dependent on filamin binding, as SHIP-2 was expressed exclusively in the cytosol of filamin-deficient cells. Recombinant SHIP-2 regulated PtdIns(3,4,5)P(3) levels and submembraneous actin at membrane ruffles after growth factor stimulation, dependent on SHIP-2 catalytic activity. Collectively these studies demonstrate that filamin-dependent SHIP-2 localization critically regulates phosphatidylinositol 3 kinase signaling to the actin cytoskeleton. |
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