Abstract
Synthesis of phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], a signaling phospholipid, is primarily carried out by phosphatidylinositol 4-phosphate 5-kinase [PI(4)P5K], which has been reported to be regulated by RhoA and Rac1. Unexpectedly, we find that the GTPgammaS-dependent activator of PI(4)P5Kalpha is the small G protein ADP-ribosylation factor (ARF) and that the activation strictly requires phosphatidic acid, the product of phospholipase D (PLD). In vivo, ARF6, but not ARF1 or ARF5, spatially coincides with PI(4)P5Kalpha. This colocalization occurs in ruffling membranes formed upon AIF4 and EGF stimulation and is blocked by dominant-negative ARF6. PLD2 similarly translocates to the ruffles, as does the PH domain of phospholipase Cdelta1, indicating locally elevated PI(4,5)P2. Thus, PI(4)P5Kalpha is a downstream effector of ARF6 and when ARF6 is activated by agonist stimulation, it triggers recruitment of a diverse but interactive set of signaling molecules into sites of active cytoskeletal and membrane rearrangement.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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ADP-Ribosylation Factor 1 / isolation & purification
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ADP-Ribosylation Factor 6
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ADP-Ribosylation Factors / isolation & purification
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ADP-Ribosylation Factors / metabolism*
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Amino Acid Sequence
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Animals
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Biological Transport
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Cattle
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Cell Compartmentation
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Cell Membrane / physiology*
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Enzyme Activation
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Guanosine 5'-O-(3-Thiotriphosphate) / metabolism
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Isoenzymes / metabolism
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Molecular Sequence Data
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Phosphatidic Acids / metabolism
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Phosphatidylinositol 4,5-Diphosphate / metabolism*
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Phospholipase D / metabolism
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Phosphotransferases (Alcohol Group Acceptor) / metabolism*
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Sequence Homology, Amino Acid
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Signal Transduction
Substances
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ADP-Ribosylation Factor 6
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Isoenzymes
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Phosphatidic Acids
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Phosphatidylinositol 4,5-Diphosphate
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Guanosine 5'-O-(3-Thiotriphosphate)
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Phosphotransferases (Alcohol Group Acceptor)
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1-phosphatidylinositol-4-phosphate 5-kinase
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phospholipase D2
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Phospholipase D
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ADP-Ribosylation Factor 1
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ADP-Ribosylation Factors