• Molecules and Cells
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• 제26권3호
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• pp.258-264
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• 2008

A rice diacylglycerol kinase (DGK) gene, OsBIDK1, which encodes a 499-amino acid protein, was cloned and characterized. OsBIDK1 contains a conserved DGK domain, consisting of a diacylglycerol kinase catalytic subdomain and a diacylglycerol kinase accessory subdomain. Expression of OsBIDK1 in rice seedlings was induced by treatment with benzothiadiazole (BTH), a chemical activator of the plant defense response, and by infection with Magnaporthe grisea, causal agent of blast disease. In BTH-treated rice seedlings, expression of OsBIDK1 was induced earlier and at a higher level than in water-treated control seedlings after inoculation with M. grisea. Transgenic tobacco plants that constitutively express the OsBIDK1 gene were generated and disease resistance assays showed that overexpression of OsBIDK1 in transgenic tobacco plants resulted in enhanced resistance against infection by tobacco mosaic virus and Phytophthora parasitica var. nicotianae. These results suggest that OsBIDK1 may play a role in disease resistance responses.

• BMB Reports
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• 제30권3호
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• pp.194-199
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• 1997

Previous studies have shown that the HD3 human enterocytic differentiated colon carcinoma cell lines having low $PKC{\beta}$ activity did not respond to diacylglycerol and basic FGF by growth and by activation of pp57 MAP kinase, but undifferentiated cell lines exhibiting high $PKC{\beta}$ activity did. To confirm a role of $PKC{\beta}$ in colonocyte mitogenesis, derivatives of HD3 cell line that stably overexpress a full-length of cDNA encoding the ${\beta}_1$ isoform of human PKC were generated. The abundance and activity of $PKC{\beta}$ in two of the these cell lines, PKC3 and PKC8 were much higher than those in the C1 control cell line that carries the vector lacking the $PKC{\beta}_1\;cDNA$ insert. Following exposure to diacylglycerol or basic FGF, proliferation of PKC3 and PKC8 cells increased about 50%; but this effect was not seen with the control C1 cells. Also, in contrast to the control cells, the $PKC{\beta}_1-overproducing$ cells displayed activation of pp57 MAP kinase when treated with diacylglycerol and basic FGF as undifferentiated cell lines did. These results provide direct evidence that $PKC{\beta}_1$ which plays a key role in mitogenic responses of colon carcinoma cells to diacylglycerol and basic FGF is down-regulated in enterocytic differentiation of colon cells.

• Biomolecules & Therapeutics
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• 제2권1호
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• pp.39-46
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• 1994

The present study was undertaken to demonstrate whether or not bradykinin activates a phospholipase D in rabbit kidney proximal tubule cells. By measuring the formation of [$^3$H]phosphatidic acid and [$^3$H]phosphatidylethanol we could elucidate the direct stimulation of phospholipase D by bradykinin. Bradykinin leads to a rapid increase in [$^3$H]phosphatidic acid and [$^3$H]diacylglycerol, and [$^3$H]phosphatidic acid formation preceded the formation of [$^3$H]diacylglycerol. This result suggests that some phosphatidic acid seems to be formed directly from phosphatidylcholine by the action of phospholipase D, not from diacylglycerol by the action of diacylglycerol kinase. In addition, the other mechanisms by which phospholipase D is activated was examined. We have found that phospholipase D was activated and regulated by extracellular calcium ion and pertussis toxin-insensitive G protein, respectively. It has also been shown that bradykinin may activate phospholipase D through protein kinase C-dependent pathway. In conclusion, we are now, for the first time, strongly suggesting that bradykinin-induced activation of phospholipase D in the rabbit kidney proximal tubule cells is mediated by a pertussis toxin-insensitive G protein and is dependent of protein kinase C.

• Archives of Pharmacal Research
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• 제17권6호
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• pp.405-410
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• 1994

The present study was undetertaken to demonstrate whether or not angiotensin II activates a phopholipase D in rabbit kidney proximal tubule cells. By measuring the formation of [$^3H$] phosphatidic acid and [$^3H$]diacylglycerol. This result suggests that some phosphatidic acid seems to be formed directly from phosphatidylcholin by the action of phopholipase D, not from the action of diacylglycerol kinase on the diacylglycerol. In addition the other mechanisms by which phospholipase D is activated was examined. We have found that phospholipase D was activited by extracellular calium ion. It has also been shown that angiotensin II may activate phosphoilpase D through protein kinase C-independent pathway.

• 한국동물학회지
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• 제32권2호
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• pp.153-162
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• 1989

난자성숙 재개와 1-세포기 배아의 세포주기에서, cAMP-의존성 protein kinase A와 diacylglycerol-의존성 protein kinase C가 핵막붕괴에 미치는 영향을 조사하였다. 난자성숙 재기는 dbcAMP, IBMX, TPA, 또는 diacyllycerol에 의해 억제되었다. 또한 protein kinase A와 protein kinase C 활성제를 같이 처리하면 난자성숙이 더욱 억제되었다. 그러나 1-세포기 배아의 전핵막붕괴에는 아무런 영향도 미치지 못하였으며, 단지 protein kinase C 활성제만이 세포질 분열을 억제하였다. 이상의 결과로부터, protein kinase A와 protein kinase C에 의한 단백질 인산화 양상이 GV난자의 핵막붕괴와 1-세포기 배아의 전핵막붕괴에 미치는 세포내 작용기작은 상이함을 알 수 있었으며, 전기영동 결과, 81 KD 단백질이 난자성숙 재개에 중요한 역할을 하리라 사료되었다.

• 한국미생물·생명공학회지
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• 제30권1호
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• pp.15-20
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• 2002

Diacylglycerol Kinase (DGK)는 E. coli 및 진핵세포에서의 신호전달에 관여하며, 또한 미생물에서 생리적 자극에 따라 다른 발현 양상을 보이는 것으로 밝혀져 있다. Bacillus subtilis에서 이 유전자에 대한 환경에서의 자극 신호들, 즉 pH 변화, 삼투압의 변화 및 온도의 변화에 따른 발현양상을 연구하였다. 이미 동정된 dgk locus의 KpnI-HindIII의 0.45 kb의 DNA fragment를 probe로 하여 Dot blot, Northern blot analysis를 통해 발현량을 조사해 본 결과 dgk 유전자는 pH변화, 삼투압의 변화 및 온도의 변화에 대응하여 발현되는 유전자임을 알 수 있었다. 특히 낮은 pH, 고 삼투압, 및 저온에서 dgk 유전자의 발현량이 많아짐을 확인 할 수 있었다. Northern hybridization에서 약 2.5kb의 mRNA가 관찰되었다. dgk gene의 ORF size는 약 0.4 kb로 관찰된 transcript size와는 일치하지 않았다. 따라서 Streptococcus mutans의 dgk gene과 마찬가지로 B. subtilis의 dgk 유전자도 polycistronic mRNA로 발현되는 것을 추정할 수 있었으며, 염색체상의 dgk gene에서 상류의 ORF2까지의 크기가 약 2.5 kb로 관찰된 mRNA size와 동일하였다. dgk gene 상류의 ORF2영역의 0.6 kb의 DNA fragment를 probe로 하여 northern blot hybridization을 수행한 결과, 2.5 kb의 mRNA가 관찰되었으며 발현되는 형태도 dgk probe를 이용한 결과와 동일하였다. 따라서 dgk gene은 상류부위의 ORF2 gene과 operon을 형성하여 polycistronic mRNA로 전사되는 것으로 판단된다.

• 미생물학회지
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• 제41권2호
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• pp.93-98
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• 2005

Sphingomonas chungbukensis DJ77의 유전체 서열분식 과정에서 969개의 nucleotide로 구성된 sphingosine kinase 유전자를 동정하였다. 이 sphingosine kinase 단백질의 아미노산 서열은 Zymomonas mobilis subsp. mobilis ZM4의 sphingosine kinase 아미노산 서열과 $55\%$의 상동성을 보였다. 또한 다중서열정렬을 통해 각각 진핵세포의 sphingosine kinase의 C2, C3, C5 domain에 속하는 3개의 conserved sequence를 발견하였다. 그 중 하나는 sphingosine kinase에서 ATP-binding site일 것으로 예상되어지는nucleotide-binding motif(GGDG)였고 나머지 둘은 아직 기능이 알려지지 않은 conserved sequences 였다. 이러한 다중서열정렬을 바탕으로 계통수를 그려본 결과, S. chungbukensis DJ77의 sphingosine kinase (SPK)는 COG1597 그룹과 유사했으며, COG1597 내에서 동일종의 diacylglycerol kinase와는 서로 다른 그룹에 속하는 것으로 나타났다. 재조합 SPK는 이종(異種)세포인 Escherichia coli내에서 성공적으로 과발현 되었으나, 세포 내에서 불용성 복합체(inclusion body)를 형성하였다.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1995년도 제3회 추계심포지움
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• pp.49-57
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• 1995

Protein kinase C (PK-C) represents a central element transducing signals generated by a broad range of pathways which produce the lipid second messenger sn-1,2-diacylglycerol (DAG) directly or indirectly. Many dominant oncogenes have proven to function, at least in part, through this pathway Likewise, this pathway is involved in expression of other aspects of the transformed phenotype, such as tumor invasion or multidrug resistance. As expected from its broad role in cell signaling, PK-C Is also important in a range of other physiological and pathophysiological processes, including inflammation, differentiation, and nerve function.

• BMB Reports
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• 제29권1호
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• pp.11-16
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• 1996

The present study showed that receptor-mediated activation of rabbit kidney proximal tubule cells by angiotensin II, the $Ca^{2+}$ ionophore A23187, or the protein kinase C activator phorbol myristate acetate (PMA) all stimulated phospholipase D (PLD). This was demonstrated by the increased formation of phosphatidic acid, and in the presence of 0.5% ethanol, phosphatidylethanol (PEt) accumulation. Angiotensin II leads to a rapid increase in phosphatidic acid and diacylglycerol, and phosphatidic acid formation preceeded the formation of diacylglycerol. This result suggests that some phosphatidic acid seems to be formed directly from phosphatidylcholine hydrolyzed by Pill. On the other hand, EGTA substantially attenuated angiotensin II and A23187-induced PEt formation, and when the cells were pretreated with verapamil angiotensin II-induced Pill activation was completely abolished. These results provide the evidence that calcium ion influx is essential for the agonist-induced Pill activation. In addition, staurosporine, an inhibitor of protein kinase C, strongly inhibited PMA-induced PEt formation, but was ineffective on angiotensin II-induced PEt accumulation. $GTP{\gamma}S$ also stimulates PEt formation in digitonin-permeabilized cells, but pretreatment of the cells with pertussis toxin failed to suppress angiotensin II-induced PEt formation. From these results, we conclude that in the rabbit kidney proximal tubule cells the mechanisms of angiotensin II- and PMA-induced Pill activation are different from each other and mediated via a pertussis toxin-insensitive trimeric G protein.

• Archives of Pharmacal Research
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• 제21권2호
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• pp.164-167
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• 1998

Bis-${\gamma}$-lactones (1,2) having a perhydrofuro[3,4-c]furan-1,4-dione skeleton were designed as conformationally constrained diacylglycerol analogues. They were synthesized from D-apiose in 11 steps, and evaluated as $PKC-{\alpha}$ ligands by measuring their ability to displace bound $^3H$]PDBU from the enzyme. The compounds showed moderate binding affinities with $K_i$ values of 13.89 (${\pm}5.67$) ${\mu}M$ and 11.47 (${\pm}0.89$) ${\mu}M$, respectively. Their similar binding affinities indicate that these two bicyclic compounds were not effectively discriminated by $PKC-{\alpha}$ in terms of the direction of the side chain as other ligands built on similar bis-${\gamma}$-lactones.