Activation of phospholipase D by protein kinase C. Evidence for a phosphorylation-independent mechanism.

Conricode, Kevin M.; Brewer, Kimberly; Exton, John H.

doi:10.1016/s0021-9258(18)42502-1

Cited by 225 publications

(19 citation statements)

References 37 publications

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“…The mechanism by which PKC activates PLD has not been fully established. In vitro studies suggest that the stimulatory activity of PKC resides in its regulatory domain, because PKC fragments devoid of catalytic domain retain their stimulatory activity in vitro, and inhibitors of catalytic activity appear to be ineffective (8). In vivo, however, as in the present study, blockers of the regulatory and catalytic domains of PKC inhibited PLD activity (1,8,9).…”

Section: Discussionsupporting

confidence: 50%

“…In vitro studies suggest that the stimulatory activity of PKC resides in its regulatory domain, because PKC fragments devoid of catalytic domain retain their stimulatory activity in vitro, and inhibitors of catalytic activity appear to be ineffective (8). In vivo, however, as in the present study, blockers of the regulatory and catalytic domains of PKC inhibited PLD activity (1,8,9). Because no evidence exists for direct phosphorylation of PLD by PKC, the effectiveness of both types of inhibitors suggests that PKC may act indirectly on PLD via an intermediate susceptible to stimulatory phosphorylation.…”

Section: Discussionmentioning

confidence: 99%

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Sequential activation of heterotrimeric and monomeric G proteins mediates PLD activity in smooth muscle

Murthy

Zhou

Grider

et al. 2001

American Journal of Physiology-Gastrointestinal and Liver Physi

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The identity of G proteins mediating CCK-stimulated phospholipase D (PLD) activity was determined in intestinal smooth muscle cells. CCK-8 activated G(q/11), G(13), and G(12), and the monomeric G proteins Ras-homology protein (RhoA) and ADP ribosylation factor (ARF). Activation of RhoA, but not ARF, was mediated by G(13) and inhibited by Galpha(13) antibody. CCK-stimulated PLD activity was partly mediated by RhoA and could be inhibited to the same extent (47 +/- 2% to 53 +/- 6%) by 1) a dominant negative RhoA mutant, 2) RhoA antibody or Galpha(13) antibody, and 3) Clostridium botulinum C3 exoenzyme. PLD activity was also inhibited by ARF antibody, and the effect was additive to that of RhoA antibody or C3 exoenzyme. PLD activity was inhibited by calphostin C, bisindolylmaleimide I, and a selective protein kinase C (PKC)-alpha inhibitor; the inhibition was additive to that of ARF and RhoA antibodies and C3 exoenzyme. In contrast, activated G(12) was not coupled to RhoA or ARF, and Galpha(12) antibody augmented PLD activity. Thus agonist-stimulated PLD activity is mediated additively by G(13)-dependent RhoA and by ARF and PKC-alpha and is modulated by an inhibitory G(12)-dependent pathway.

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Section: Discussionsupporting

confidence: 50%

Section: Discussionmentioning

confidence: 99%

Sequential activation of heterotrimeric and monomeric G proteins mediates PLD activity in smooth muscle

Murthy

Zhou

Grider

et al. 2001

American Journal of Physiology-Gastrointestinal and Liver Physi

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“…PLD catalyzes the hydrolysis of phospholipids to yield phosphatidic acid (PA) and the free polar headgroups. PA has been implicated as a biologically active molecule and has been found to be metabolized by a PA phosphohydrolase to form diacylglycerol, a protein kinase C activator (2,(6)(7)(8)(9)(10). When added exogenously to cells, PA has been found to stimulate phospholipase A 2 activity (11,12).…”

mentioning

confidence: 99%

Specific inhibition of rat brain phospholipase D by lysophospholipids

Ryu

Palta

2000

Journal of Lipid Research

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Although the importance of phospholipase D (PLD) in signal transduction in mammalian cells is well documented, the negative regulation of PLD is poorly understood. This is primarily due to a lack of known specific inhibitors of PLD. We herein report that the activity of partially purified rat brain PLD is inhibited by certain lysophospholipids, such as lysophosphatidylinositol, lysophosphatidylglycerol, and lysophosphatidylserine in a highly specific manner. Inhibition of PLD by lysophospholipids was dosedependent: the concentration of lysophosphatidylinositol required for half-maximal inhibition was about 3 m . An analysis of the enzyme-kinetics suggested that lysophospholipids act as non-competitive inhibitors of PLD activity. As expected, PLD activity was stimulated by ADP-ribosylation factor (Arf) and phosphatidylinositol 4,5-bisphosphate (PIP 2 ). The inhibition of PLD by lysophospholipids, however, was not affected by the presence or absence of Arf or by an increase in PIP 2 concentration. A protein-binding assay suggested that lysophospholipids bind directly to PLD. These results indicate that the observed inhibition of PLD by lysophospholipids is due to their direct interaction rather than to an interaction between lysophospholipids and either Arf or PIP 2 . The present study suggests that certain lysophospholipids are specific inhibitors of rat brain PLD in a cell-free system and may provide the new opportunities to investigate mechanisms by which PLD is regulated by lysophospholipids, presumably liberated by phospholipase A 2 activation, in mammalian cells. -Ryu, S. B. and J. P. Palta. Specific inhibition of rat brain phospholipase D by lysophospholipids.

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“…By dissecting the vesicle generation process into sequential stages of coat assembly/bud formation and vesicle scission, we were able to show that PKC inhibitors suppress vesicle scission without preventing coat assembly, yet, to exert their effect, they must be present before coat assembly takes place. These observations raise the possibility that PLD, a PKC target, which can be activated by PKC in the absence of the latter's phosphorylating activity (Conricode et al, 1992;Singer et al, 1996), plays an essential role in remodeling the phospholipid bilayer that is required for vesicle scission.…”

mentioning

confidence: 99%

The production of post-Golgi vesicles requires a protein kinase C-like molecule, but not its phosphorylating activity.

Simon

Ivanov

Adesnik

et al. 1996

The Journal of Cell Biology

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Abstract. We have recently described a system that recreates in vitro the generation of post-Golgi vesicles from purified Golgi fractions obtained from virusinfected MDCK cells in which the vesicular stomatitis virus-G envelope glycoprotein had been allowed to accumulate in vivo in the TGN. Vesicle formation, monitored by the release of the viral glycoprotein, was shown to require the activation of a GTP-binding ADP ribosylation factor (ARF) protein that promotes the assembly of a vesicle coat in the TGN, and to be regulated by a Golgi-associated protein kinase C (PKC)-like activity. We have now been able to dissect the process of post-Golgi vesicle generation into two sequential stages, one of coat assembly and bud formation, and another of vesicle scission, neither of which requires an ATP supply. The first stage can occur at 20°C, and includes the GTP-dependent activation of the ARF protein, which can be effected by the nonhydrolyzable nucleotide analogue GTP'yS, whereas the second stage is nucleotide independent and can only occur at a higher temperature of incubation. Cytosolic proteins are required for the vesicle scission step and they cannot be replaced by palmitoyl CoA, which is known to promote, by itself, scission of the coatomercoated vesicles that mediate intra-Golgi transport. We have found that PKC inhibitors prevented vesicle generation, even when this was sustained by GTP~/S and ATP levels reduced far below the Km of PKC. The inhibitors suppressed vesicle scission without preventing coat assembly, yet to exert their effect, they had to be added before coat assembly took place. This indicates that a target of the putative PKC is activated during the bud assembly stage of vesicle formation, but only acts during the phase of vesicle release. The behavior of the PKC target during vesicle formation resembles that of phospholipase D (PLD), a Golgi-associated enzyme that has been shown to be activated by PKC, even in the absence of the latter's phosphorylating activity. We therefore propose that during coat assembly, PKC activates a PLD that, during the incubation at 37°C, promotes vesicle scission by remodeling the phospholipid bilayer and severing connections between the vesicles and the donor membrane.XTENSIVE studies on the formation of clathrincoated vesicles at the plasma membrane (for review see Robinson, 1994) and the TGN (Robinson and Kreis, 1992;Traub et al., 1993;Wong and Brodsky, 1992), and of the COPI-and COPII-coated vesicles that affect ER to Golgi and intra-Golgi transport (Barlowe et al., 1994;Bednarek et al., 1995;Ostermann et al., 1993;Salama and Schekman, 1995), have shown that the formation of a transport vesicle is initiated by the assembly of a protein coat on the donor membrane from cytosolic components. The coat is thought to serve as a mechanochemical device that imparts to the membrane the high degree of curvature necessary to form a budding vesicle (Pryer et al., 1992). The formation of a bud is followed by a second, notPlease address all correspondence to David D. Sabatini,...

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Activation of phospholipase D by protein kinase C. Evidence for a phosphorylation-independent mechanism.

Cited by 225 publications

References 37 publications

Sequential activation of heterotrimeric and monomeric G proteins mediates PLD activity in smooth muscle

Sequential activation of heterotrimeric and monomeric G proteins mediates PLD activity in smooth muscle

Specific inhibition of rat brain phospholipase D by lysophospholipids

The production of post-Golgi vesicles requires a protein kinase C-like molecule, but not its phosphorylating activity.

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