• Journal of the Korean Chemical Society
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• v.47 no.5
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• pp.466-471
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• 2003

The effect of polyamines on the cabbage phospholipase D(PLD) activity was investigated. The PLD activity was determined by pH-stat titration of phosphatidic acid, one of the enzymatic reaction product, using phosphatidyl choline small unilamellar vesicles as a substrate. The cabbage PLD was activated approximately 4 fold by spermine at 1 mM concentration. This spermine effect appears to be similar to the previous report on the PLD activation of rat brain mitochondrial fraction. It was also found that cationic polypetides such as polylysine and polyhistidine exerted a marked enhancement effect on the cabbage PLD. Particularly polyhistidine exerted approximately 5.5 fold enhancement effect at 0.062 mM concentration. The polyamine effect on the cabbage PLD was reexamined in the phosphatidylcholine/sodium dodecyl sulfate mixed micellar system. The relevance of polyamine effect on PLD activity is discussed in relation to the active site of PLD.

• Journal of Life Science
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• v.13 no.6
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• pp.903-910
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• 2003

Phospholipase D (PLD) plays an important role as a signaling molecule in the activation of neutrophils. In this study, effect of nitric oxide (NO) and cGMP on the activation of PLD in human neutrophils was investigated. Sodium nitroprusside (SNP), an agent to produce NO spontaneously in cells, alone increased PLD activity and the maximal activation was obtained with 0.5 mM SNP. Dibutyryl-cAMP, an agent to increase an intracellular cAMP concentration inhibited formyl-Met-Leu-Phe (fMLP)-stimulated PLD activity but 8-bromo-cGMP (300 $\mu$M), an agent to increase an intracellular cGMP concentration did not affect basal and fMLP-stimulated PLD activity. NO-induced activation of PLD was not blocked by KT 5823, an inhibitor of cGMP-dependent protein kinase (PKG), suggesting that NO-induced PLD activation is not mediated by cGMP. NO also stimulated p38 mitogen activated protein kinase (MAPK) in human neutrophils, indicated by increased phosphorylation of p38 MAPK in Western blotting. NO-induced phosphorylation of p38 MAPK was not inhibited by KT 5823 or n-butanol. RhoA, an regulatory factor of PLD activation was trans-located from cytosolic fraction to plasma membranes by fMLP or phorbol ester, and fMLP-stimulated but not phorbol ester-stimulated translocation of RhoA was inhibited by cGMP. These results suggest that NO stimulates PLD activity through other unidentified facto.(s) than cGMP even though cGMP inhibits the artivation of RhoA.

• BMB Reports
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• v.34 no.2
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• pp.182-187
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• 2001

Phospholiapse D (PLD), and phosphatidic acid generated by it, have been implicated in receptor-mediated intracellular signaling. Carbachol (CCh) is known to activate PLD1, and protein kinase C (PKC) is known to mediate in this signaling pathway In recent reports (Kim et al., 1999b; Kim et al., 2000), we published our observations of the direct phosphorylation of PLD1 by PKC and we described the phosphorylation-dependent regulation of PLD1 activity. In this study, we investigated the phasphorylation and compartmentalization of PLD1 in terms of CCh signaling in M3 muscarinic receptor (M3R)-expressing COS-7 cells. CCh treatment of COS-7 cells transiently coexpressing PLD1 and M3R stimulated PLD1 activity and induced direct phosphorylation of PLD1 by PKC. The CCh-induced activation and phosphorylation of PLD1 was completely blocked upon pretreatment of the cells with PKC-specific inhibitors. We looked at the localization of the PLD1 phosphorylation by PKC and found that PLD1 was mainly located in the caveolin-enriched membrane (CEM) fraction. Based on these results, we conclude that CCh induces the activation and phosphorylation of PLD1 via PKC and that the phosphorylation of PLD1 occurs in caveolae.

• BMB Reports
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• v.44 no.9
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• pp.572-577
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• 2011

Elevated phospholipase D (PLD) expression prevents cell cycle arrest and apoptosis. However, the roles of PLD isoforms in cell proliferation and apoptosis are incompletely understood. Here, we investigated the physiological significance of the interaction between PLD2 and protein kinase CKII (CKII) in HCT116 human colorectal carcinoma cells. PLD2 interacted with the CKII${\beta}$ subunit in HCT116 cells. The C-terminal domain (residues 578-933) of PLD2 and the N-terminal domain of CKII${\beta}$ were necessary for interaction between the two proteins. PLD2 relocalized CKII${\beta}$ to the plasma membrane area. Overexpression of PLD2 reduced CKII${\beta}$ protein level, whereas knockdown of PLD2 led to an increase in CKII${\beta}$ expression. PLD2-induced CKII${\beta}$ reduction was mediated by ubiquitin-dependent degradation. The C-terminal domain of PLD2 was sufficient for CKII${\beta}$ degradation as the catalytic activity of PLD2 was not required. Taken together, the results indicate that the C-terminal domain of PLD2 can regulate CKII by accelerating CKII${\beta}$ degradation in HCT116 cells.

• 전기의세계
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• v.38 no.9
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• pp.35-45
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• 1989

최근 정보 및 산업사회의 발달에 따라 전기에너지의 이용이 양적, 수적으로 증가되고 있는 가운데 모든 전기.전자기기 및 전력설비에 전기에너지를 전달하는 전력선로상에서 불요전기신호에 의한 전원방해현상이 발생되는 경우가 빈번해 지고 있다. 따라서 기기의 정상적인 동작에 장애를 주는 증 PLD현상이 심각해지고 있는 실정이다. 그러므로 PLD현상파악 및 이에 대한 방지대책의 수립은 EMI/EMC문제의 가장 기본적이라고 할 수 있다. 먼저 PLD에 대한 실태조사가 뒤따라야 할 것이다. 또는 국내 여러지역을 전력수요가별로 구분하여 PLD현상을 측정할 필요가 있다. 그리고 측정된 데이터의 분석에 의해 각종 전기.전자기기 등의 효율적 운용을 보장하기 위해서는 PLD현상에 대한 대책을 법적규제의 측면과 잡음대책방안의 측면에서 제시해야 할 것이다.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.10
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• pp.102-110
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• 1995

This paper describes a development of the PLD design tool in considering with a device fitting. To design digital circuit with PLDs, several steps in the developed PLD design tool are needed such as Boolean description step, pin map step, FUSE map and JEDEC steps ... etc. Especially, we have considered the device fitting to design large digital circuits with PLDs developed the device fitting algorithms based on the PLD device fitting and compared with the results of a another PLD design tool(PALASM). Also, we have proved that the developed PLD design tool is successfully implemented by the connection with a PLD writer(ALL-07), in the case of design digital circuits.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.4
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• pp.223-229
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• 2003

Using phospholipase D1 (PLD1)-overexpressing PC12 (PLD1-PC12) cells, the regulatory roles of PLD1 on ATP-induced currents were investigated. In control and PLD1-PC12 cells, ATP increased PLD activity in an external $Ca^{2+}$ dependent manner. PLD activity stimulated by ATP was substantially larger in PLD1-PC12 cells than in control cells. In whole-cell voltage-clamp mode, ATP induced transient inward and outward currents. The outward currents inhibited by TEA or charybdotoxin were significantly larger in PLD1-PC12 cells than in control cells. The inward currents known as $Ca^{2+}$ permeable nonselective cation currents were also larger in PLD1-PC12 cells than in control cells. However, the difference between the two groups of cells disappeared in $Ca^{2+}$-free external solution, where ATP did not activate PLD. Finally, ATP-induced $^{45}Ca$ uptakes were also larger in PLD1-PC12 cells than in control cells. These results suggest that PLD enhances ATP-induced $Ca^{2+}$ influx via $Ca^{2+}$ permeable nonselective cation channels and increases subsequent $Ca^{2+}$-activated $K^+$ currents in PC12 cells.

• Journal of Microbiology and Biotechnology
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• v.13 no.6
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• pp.897-905
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• 2003

Phospholipase D (PLD) and ADP-ribosylation factor (ARF) were partially purified on a series of column chromatography, and their biochemical properties were characterized to understand the regulatory mechanism of PLD activation by ARF protein in the antigen-induced immune responses in guinea pigs. Heparin Sepharose and high-Q Sepharose column chromatographies were used for the purification of PLD, and Sephadex G-25, DEAE Sephacel, Source 15 PHE (HIC), Superdex-75, and Uno-Q column chromatographies were used for the purification of ARF. The purified PLD and ARF proteins were identified with anti-rabbit PLD- or ARF-specific antibodies, showing about 64 or 85 kDa for the molecular mass of PLD and 29 or 35 kDa for the sizes of ARF. Partial cDNA of ARF3 was cloned by RT-PCR in guinea pig lung tissue and its nucleotides and amino acids were sequenced. Guinea pig ARF3 showed 92% of nucleotides sequence identity and 100% of amino acid sequence homology with human ARF3. The ARF-regulated PLD activity was measured in the oleate or ARFs-containing mixed lipid vesicles. The purified and recombinant ARF (rARF) activities were assessed with the $GTP{\gamma}S$ binding assay. The PLD activity was induced by oleate in a dose-dependent manner. The purified ARF and recombinant ARF3 increased PLD activity in guinea pig lung tissues. These data show that the activity of membrane-bound PLD can be regulated by the cytosolic ARF proteins, suggesting that ARF proteins in guinea pig lung can act as a regulatory factor in controlling the PLD activity in allergic reaction.

• Korean Journal of Microbiology
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• v.42 no.4
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• pp.294-298
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• 2006

An immunoaffinity chromatography for the specific binding of Streptomyces somaliensis phospholipase D (PLD) that is considered as an industrially potential enzyme was developed. By using the protein structure prediction programs and the X-ray crystal structure of a Streptomyces PLD, 5 different epitopes with high antigenicity that are predicted to locate on the surface of the S. somaliensis PLD were selected and then synthesized for the preparation of antipeptide antibodies. Each purified rabbit IgG was coupled with NHS-activated Sepharose to prepare the immunoaffinity resins. After one-step purification of the culture concentrate on the antipeptide IgG-coupled Sepharose column, SDS-PAGE and the Western blot analysis of the purified samples showed that purification of PLD on the affinity columns was satisfactory, indicating that the peptide design using the structural information of Streptomyces PLDs was rational. However, the purified PLD in the solution aggregated rapidly, which resulted in poor specific activity and low purification yield.

• Journal of Life Science
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• v.13 no.5
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• pp.551-558
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• 2003

Hepatitis C Virus (HCV) is associated with a severe liver disease and increased frequency in the development of hepatocellular carcinoma. Overexpression of HCV core protein is known to transform fibroblast cells. Phospholipase D (PLD) activity is commonly elevated in response to mitogenic signals, and PLD has been also reported to be overexpressed and hyperactivated in some human cancer. The aim of this study was to understand how PLD can be regulated in HCV core protein-transformed NIH3T3 mouse fibroblast cells. We observed that in unstimulated state, basal PLD activity was higher in NIH3T3 cells overexpressing HCV core protein than in vector-transfected cells. Although expression of PLD and protein kinase C (PKC) in core protein-transformed cells was similar with that of control cells, phorbol 12-myristate 13-acetate (PMA), which is known to activate PKC, stimulated significantly PLD activity in core protein-transformed cells, compared with that of the control cells. PLD activity assay using PKC isozyme-specific inhibitor, and PKC translocation experiment showed that PKC-$\delta$ was mainly involved in the PMA-induced PLD activation in the core-transformed cells. Taken together, these results suggest that PLD might be implicated in core protein-induced transformation.