Membrane Ruffling Requires Coordination between Type Iα Phosphatidylinositol Phosphate Kinase and Rac Signaling
| Autor: | Matthew W. Bunce, Ari J. Firestone, Richard A. Anderson, Michelle L. Wojtasiak, Renee L. Doughman |
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| Rok vydání: | 2003 |
| Předmět: |
Membrane ruffling
Morpholines Biology Biochemistry Cell Line Minor Histocompatibility Antigens chemistry.chemical_compound Actin remodeling of neurons Humans Phosphatidylinositol Cloning Molecular Enzyme Inhibitors Molecular Biology Actin DNA Primers Platelet-Derived Growth Factor Microscopy Confocal Base Sequence Kinase Cell Membrane Actin remodeling Cell Biology Fibroblasts Recombinant Proteins rac GTP-Binding Proteins Cell biology Phosphotransferases (Alcohol Group Acceptor) Amino Acid Substitution chemistry Chromones Mutagenesis Site-Directed Phosphatidylinositol phosphate kinases Signal transduction Signal Transduction |
| Zdroj: | Journal of Biological Chemistry. 278:23036-23045 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.m211397200 |
| Popis: | Membrane ruffle formation requires remodeling of cortical actin filaments, a process dependent upon the small G-protein Rac. Growth factors stimulate actin remodeling and membrane ruffling by integration of signaling pathways that regulate actin-binding proteins. Phosphatidylinositol 4,5-bisphosphate (PIP2) regulates the activity of many actin-binding proteins and is produced by the type I phosphatidylinositol phosphate kinases (PIPKIs). Here we show in MG-63 cells that only the PIPKIalpha isoform is localized to platelet-derived growth factor (PDGF)-induced membrane ruffles. Further, expression of kinase dead PIPKIalpha, which acts as a dominant negative mutant, blocked membrane ruffling, suggesting that PIPKIalpha and PIP2 participate in ruffling. To explore this, PIPKIalpha was overexpressed in serum-starved cells and stimulated with PDGF. In serum-starved cells, PIPKIalpha expression did not stimulate actin remodeling, but when these cells were stimulated with PDGF, actin rapidly reorganized into foci but not membrane ruffles. PIPKIalpha-mediated formation of actin foci was independent of both Rac1 and phosphatidylinositol 3-kinase activities. Significantly, coexpression of dominant active Rac1 with PIPKIalpha in PDGF-stimulated cells resulted in membrane ruffling. The PDGF- and Rac1-stimulated ruffling was inhibited by expression of kinase-dead PIPKIalpha. Combined, these data support a model where the localized production of PIP2 by PIPKIalpha is necessary for actin remodeling, whereas formation of membrane ruffles required Rac signaling. |
| Databáze: | OpenAIRE |
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