Direct Modulation of Phospholipase D Activity by Gβγ

Department of Pharmacology, Vanderbilt University, Нашвилл, Michigan, United States
Molecular Pharmacology (Impact Factor: 4.13). 08/2006; 70(1):311-8. DOI: 10.1124/mol.105.021451
Source: PubMed


Phospholipase D-mediated hydrolysis of phosphatidylcholine is stimulated by protein kinase C and the monomeric G proteins Arf, RhoA, Cdc42, and Rac1, resulting in complex regulation of this enzyme. Using purified proteins, we have identified a novel inhibitor of phospholipase D activity, Gbetagamma subunits of heterotrimeric G proteins. G protein-coupled receptor activation alters affinity between Galpha and Gbetagamma subunits, allowing subsequent interaction with distinct effectors. Gbeta1gamma1 inhibited phospholipase D1 and phospholipase D2 activity, and both Gbeta1gamma1 and Gbeta1gamma2 inhibited stimulated phospholipase D1 activity in a dosedependent manner in reconstitution assays. Reconstitution assays suggest this interaction occurs through the amino terminus of phospholipase D, because Gbeta1gamma1 is unable to inhibit an amino-terminally truncated phospholipase D construct, PLD1.d311, which like full-length phospholipase D isoforms, requires phosphatidylinositol-4,5-bisphosphate for activity. Furthermore, a truncated protein consisting of the amino-terminal region of phospholipase D containing the phox/pleckstrin homology domains was found to interact with Gbeta1gamma1, unlike the PLD1.d311 recombinant protein, which lacks this domain. In vivo, expressed recombinant Gbeta1gamma2 was also found to inhibit phospholipase D activity under basal and stimulated conditions in MDA-MB-231 cells, which natively express both phospholipase D1 and phospholipase D2. These data demonstrate that Gbetagamma directly regulates phospholipase D activity in vitro and suggest a novel mechanism to negatively regulate phospholipase D signaling in vivo.

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Available from: Anita M Preininger, Nov 07, 2015
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    • "Although a direct interaction between metazoan PLD and Ga has, to our knowledge, not been described, metazoan PLD activity has been shown to be negatively regulated by Gb 1 c 1 and Gb 1 c 2 in vitro and by Gb 1 c 1 in vivo (Preininger et al., 2006). This suggests that a signaling mechanism common to eukaryotes might exist wherein PLDs are regulated by direct interaction with both Ga and Gbc. "
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