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Sun B, Lin S, Zheng M, Zheng B, Mao L, Gu Y, Cai J, Dai Y, Zheng M, Lou Y. Phosphatidylinositol-specific phospholipase C can decrease Müller cell viability and suppress its phagocytic activity by modulating PI3K/AKT signaling pathway. Can J Microbiol 2023; 69:501-511. [PMID: 37672795 DOI: 10.1139/cjm-2023-0044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/08/2023]
Abstract
Bacillus cereus endophthalmitis is a devastating eye infection that causes rapid blindness through the release of extracellular tissue-destructive exotoxins. The phagocytic and antibacterial functions of ocular cells are the keys to limiting ocular bacterial infections. In a previous study, we identified a new virulence gene, plcA-2 (different from the original plcA-1 gene), that was strongly associated with the plcA gene of Listeria monocytogenes. This plcA gene had been confirmed to play an important role in phagocytosis. However, how the Bc-phosphatidylinositol-specific phospholipase C (PI-PLC) proteins encoded by the plcA-1/2 genes affect phagocytes remains unclear in B. cereus endophthalmitis. Here, we found that the enzymatic activity of Bc-PI-PLC-A2 was approximately twofold higher than that of Bc-PI-PLC-A1, and both proteins inhibited the viability of Müller cells. In addition, PI-PLC proteins reduced phagocytosis of Müller cells by decreasing the phosphorylation levels of key proteins in the PI3K/AKT signaling pathway. In conclusion, we showed that PI-PLC proteins contribute to inhibit the viability of and suppress the phagocytosis of Müller cells, providing new insights into the pathogenic mechanism of B. cereus endophthalmitis.
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Affiliation(s)
- Bianjin Sun
- Zhejiang Provincial Key Laboratory for Technology and Application of Model Organisms, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - Shudan Lin
- Zhejiang Provincial Key Laboratory for Technology and Application of Model Organisms, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
- Department of Clinical Laboratory, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center For Child Health, Hangzhou, China
| | - Mengmeng Zheng
- Zhejiang Provincial Key Laboratory for Technology and Application of Model Organisms, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Beijia Zheng
- Zhejiang Provincial Key Laboratory for Technology and Application of Model Organisms, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
- Department of Clinical Laboratory, Taizhou Central Hospital (Taizhou University Hospital), Taizhou, China
| | - Liping Mao
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - Yunfeng Gu
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - Jiabei Cai
- Zhejiang Provincial Key Laboratory for Technology and Application of Model Organisms, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - Yiran Dai
- Zhejiang Provincial Key Laboratory for Technology and Application of Model Organisms, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Meiqin Zheng
- Zhejiang Provincial Key Laboratory for Technology and Application of Model Organisms, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - Yongliang Lou
- Zhejiang Provincial Key Laboratory for Technology and Application of Model Organisms, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
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Grandgenett PM, Otsu K, Wilson HR, Wilson ME, Donelson JE. A function for a specific zinc metalloprotease of African trypanosomes. PLoS Pathog 2007; 3:1432-45. [PMID: 17953481 PMCID: PMC2034397 DOI: 10.1371/journal.ppat.0030150] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Accepted: 09/04/2007] [Indexed: 11/19/2022] Open
Abstract
The Trypanosoma brucei genome encodes three groups of zinc metalloproteases, each of which contains approximately 30% amino acid identity with the major surface protease (MSP, also called GP63) of Leishmania. One of these proteases, TbMSP-B, is encoded by four nearly identical, tandem genes transcribed in both bloodstream and procyclic trypanosomes. Earlier work showed that RNA interference against TbMSP-B prevents release of a recombinant variant surface glycoprotein (VSG) from procyclic trypanosomes. Here, we used gene deletions to show that TbMSP-B and a phospholipase C (GPI-PLC) act in concert to remove native VSG during differentiation of bloodstream trypanosomes to procyclic form. When the four tandem TbMSP-B genes were deleted from both chromosomal alleles, bloodstream B (-/-) trypanosomes could still differentiate to procyclic form, but VSG was removed more slowly and in a non-truncated form compared to differentiation of wild-type organisms. Similarly, when both alleles of the single-copy GPI-PLC gene were deleted, bloodstream PLC (-/-) cells could still differentiate. However, when all the genes for both TbMSP-B and GPI-PLC were deleted from the diploid genome, the bloodstream B (-/-) PLC (-/-) trypanosomes did not proliferate in the differentiation medium, and 60% of the VSG remained on the cell surface. Inhibitors of cysteine proteases did not affect this result. These findings demonstrate that removal of 60% of the VSG during differentiation from bloodstream to procyclic form is due to the synergistic activities of GPI-PLC and TbMSP-B.
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Affiliation(s)
- Paul M Grandgenett
- Interdepartmental Genetics Program, University of Iowa, Iowa City, Iowa, United States of America
| | - Keiko Otsu
- Department of Biochemistry, University of Iowa, Iowa City, Iowa, United States of America
| | - Helen R Wilson
- Department of Biochemistry, University of Iowa, Iowa City, Iowa, United States of America
| | - Mary E Wilson
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States of America
- Department of Microbiology, University of Iowa, Iowa City, Iowa, United States of America
- Veterans Affairs Medical Center, Iowa City, Iowa, United States of America
| | - John E Donelson
- Interdepartmental Genetics Program, University of Iowa, Iowa City, Iowa, United States of America
- Department of Biochemistry, University of Iowa, Iowa City, Iowa, United States of America
- * To whom correspondence should be addressed. E-mail:
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Affiliation(s)
- Robin Irvine
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, UK.
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Lo Vasco VR, Fabrizi C, Artico M, Cocco L, Billi AM, Fumagalli L, Manzoli FA. Expression of phosphoinositide-specific phospholipase C isoenzymes in cultured astrocytes. J Cell Biochem 2007; 100:952-9. [PMID: 17063484 DOI: 10.1002/jcb.21048] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Signal transduction from plasma membrane to cell nucleus is a complex process depending on various components including lipid signaling molecules, in particular phosphoinositides and their related enzymes, which act at cell periphery and/or plasma membrane as well as at nuclear level. As far as the nervous system may concern the inositol lipid cycle has been hypothesized to be involved in numerous neural as well as glial functions. In this context, however, a precise panel of glial PLC isoforms has not been determined yet. In the present experiments we investigated astrocytic PLC isoforms in astrocytes obtained from foetal primary cultures of rat brain and from an established cultured (C6) rat astrocytoma cell line, two well known cell models for experimental studies on glia. Identification of PLC isoforms was achieved by using a combination of RT-PCR and immunocytochemistry experiments. While in both cell models the most represented PI-PLC isoforms were beta4, gamma1, delta4, and epsilon, isoforms PI-PLC beta2 and delta3 were not detected. Moreover, in primary astrocyte cultures PI-PLC delta3 resulted well expressed in C6 cells but was absent in astrocytes. Immunocytochemistry performed with antibodies against specific PLC isoforms substantially confirmed this pattern of expression both in astrocytes and C6 glioma cells. In particular while some isoenzymes (namely isoforms beta3 and beta4) resulted mainly nuclear, others (isoforms delta4 and epsilon) were preferentially localized at cytoplasmic and plasma membrane level.
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Affiliation(s)
- Vincenza Rita Lo Vasco
- Department of Fisiologia e Farmacologia V Erspamer, Respiratorie e Morfologiche, University of Rome La Sapienza, Rome, Italy
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Hellrung DJ, Kisselev S, Link CJ. Co-expression of alpha(1,3)galactosyltransferase and Bacillus thuringiensis PIPLC enhances hyperacute rejection of tumor cells. Cancer Immunol Immunother 2007; 56:25-34. [PMID: 16612594 PMCID: PMC11030725 DOI: 10.1007/s00262-006-0163-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2006] [Accepted: 03/15/2006] [Indexed: 11/29/2022]
Abstract
The use of alpha(1,3)galactosyltransferase (alphaGT) as a method of inducing hyperacute rejection of tumors has been gaining interest recently. However, the approach is based in part on the sensitivity of each tumor line to the effects of complement lysis. Tumors expressing complement resistance factors such as membrane cofactor (CD46), decay accelerating factor (CD55) and protectin (CD59) have been shown to be more resistant to complement mediated lysis. Anchored to the membrane by a glycosylphosphoinositol moiety (GPI-anchored), CD55 and CD59 can be cleaved by Bacillus thuringiensis phosphatidylinositol-specific phospholipase C (PIPLC). Complement resistant A549 human lung carcinoma cells were engineered to express both the murine alphaGT gene and the B. thuringiensis PIPLC gene to alleviate complement resistance and enhance alphagal-mediated cancer killing. The PIPLC native signal sequence was replaced with the human epidermal growth factor signal sequence, EGFssPIPLC, to induce secretion from A549. Expression of EGFssPIPLC resulted in complete removal of CD55 and CD59 while sparing the non-GPI-anchored CD46. Results demonstrated that A549 cells transduced with two recombinant retroviral vectors carrying the alphaGT and EGFssPIPLC genes expressed high levels of alphagal epitope and exhibited a 5-fold increase in sensitivity to anti-alphagal mediated complement lysis.
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Affiliation(s)
- Daniel J. Hellrung
- Iowa Cancer Research Foundation, 11043 Aurora Avenue, Urbandale, IA 50322 USA
- Iowa State University, Ames, IA USA
| | - Serguei Kisselev
- Iowa Cancer Research Foundation, 11043 Aurora Avenue, Urbandale, IA 50322 USA
| | - Charles J. Link
- Iowa Cancer Research Foundation, 11043 Aurora Avenue, Urbandale, IA 50322 USA
- Iowa State University, Ames, IA USA
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Kawakami A, Aikawa M, Nitta N, Yoshida M, Libby P, Sacks FM. Apolipoprotein CIII-induced THP-1 cell adhesion to endothelial cells involves pertussis toxin-sensitive G protein- and protein kinase C alpha-mediated nuclear factor-kappaB activation. Arterioscler Thromb Vasc Biol 2006; 27:219-25. [PMID: 17038637 DOI: 10.1161/01.atv.0000249620.68705.0d] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Plasma apolipoprotein CIII (apoCIII) independently predicts risk for coronary heart disease (CHD). We recently reported that apoCIII directly enhances adhesion of human monocytes to endothelial cells (ECs), and identified the activation of PKC alpha as a necessary upstream event of enhanced monocyte adhesion. This study tested the hypothesis that apoCIII activates PKC alpha in human monocytic THP-1 cells, leading to NF-kappaB activation. METHODS AND RESULTS Among inhibitors specific to PKC activators, phosphatidylcholine-specific phospholipase C (PC-PLC) inhibitor D609 limited apoCIII-induced PKC alpha activation and THP-1 cell adhesion. ApoCIII increased PC-PLC activity in THP-1 cells, resulting in PKC alpha activation. Pertussis toxin (PTX) inhibited apoCIII-induced PC-PLC activation and subsequent PKC alpha activation, implicating PTX-sensitive G protein pathway. ApoCIII further activated nuclear factor-kappaB (NF-kappaB) through PKC alpha in THP-1 cells and augmented beta1-integrin expression. The NF-kappaB inhibitor peptide SN50 partially inhibited apoCIII-induced beta1-integrin expression and THP-1 cell adhesion. ApoCIII-rich VLDL had similar effects to apoCIII alone. CONCLUSIONS PTX-sensitive G protein pathway participates critically in PKC alpha stimulation in THP-1 cells exposed to apoCIII, activating NF-kappaB, and increasing beta1-integrin. This action causes monocytic cells to adhere to endothelial cells. Furthermore, because leukocyte NF-kappaB activation contributes to inflammatory aspects of atherogenesis, apoCIII may stimulate diverse inflammatory responses through monocyte activation.
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Affiliation(s)
- Akio Kawakami
- Department of Nutrition, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA
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Follo MY, Bosi C, Finelli C, Fiume R, Faenza I, Ramazzotti G, Gaboardi GC, Manzoli L, Cocco L. Real-time PCR as a tool for quantitative analysis of PI-PLCbeta1 gene expression in myelodysplastic syndrome. Int J Mol Med 2006; 18:267-71. [PMID: 16820933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023] Open
Abstract
Phosphoinositide-specific phospholipase C (PI-PLC) beta1 is a key enzyme in nuclear signal transduction, and it is involved in many cellular processes, such as proliferation and differentiation. In particular, the involvement of the PI-PLCbeta1 gene in erythroid differentiation lead us to investigate this gene in patients affected by high-risk myelodysplastic syndrome (MDS). By using fluorescence in situ hybridization (FISH) analysis, we have previously evidenced that, in MDS patients with normal GTG banding and a fatal outcome, the PI-PLCbeta1 gene undergoes monoallelic and interstitial deletion. Real-time PCR is characterized by high sensitivity, excellent precision and large dynamic range, and has become the method of choice for quantitative gene expression measurements. In the present study, we have performed a relative quantification real-time polymerase chain reaction (PCR) analysis on all of the MDS patients tested for FISH analysis. Furthermore, we have evaluated the expression of the PI-PLCbeta1 gene on healthy donors and the HL60 cell line, which is useful for testing the accuracy of the technology because of its low expression of PI-PLCbeta1. To analyze and quantify the levels of the two different splicing variants of PI-PLCbeta1 gene (1a and 1b), we have used a TaqMan isoform specific probe. We have seen that all of the MDS patients have higher levels of the PI-PLCbeta1 mRNA compared to the HL60 cell line as expected, but lower levels compared to the healthy donors. Furthermore, MDS blasts always express higher levels of PI-PLCbeta1b mRNA compared to PI-PLCbeta1a mRNA. Our data support the contention that the deletion of the PI-PLCbeta1 gene is indeed responsible for a reduced expression of the enzyme. In addition, the splicing isoform 1b, which is only nuclear, seems to be somehow partially preserved compared to the 1a isoform, which is nuclear and cytoplasmatic, hinting at a possible imbalance of the nuclear versus cytoplasmatic PI-PLC signaling which, in turn, could affect the cell cycle progression of MDS blasts.
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Affiliation(s)
- Matilde Y Follo
- Department of Anatomical Sciences, Cellular Signalling Laboratory, University of Bologna, 40126 Bologna, Italy
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Abstract
The Toxoplasma gondii phosphoinositide-specific phospholipase C gene (TgPI-PLC) was cloned, sequenced and expressed in Escherichia coli and its enzymatic characteristics were investigated. TgPI-PLC is present in the genome as a single-copy gene consisting of 22 exons interrupted by 21 introns, and encodes a polypeptide of 1097 amino acids with a predicted molecular mass of 121 kDa. In addition to the conserved catalytic X and Y domains, TgPI-PLC contains an apparent N-terminal PH domain, an EF hand motif and a C-terminal C2 domain. When compared with mammalian delta-type PI-PLC, TgPI-PLC has an additional extended N-terminus and two insertions in the region between the X and Y domains, with a 31-35% identity over the whole sequence. Recombinant TgPI-PLC, as well as the native enzyme obtained from crude membrane extracts of the parasite, was more active with phosphatidylinositol than with phosphatidylinositol 4,5-bisphosphate as substrate. Indirect immunofluorescence analysis using an affinity-purified antibody against TgPI-PLC revealed that this enzyme localizes in the plasma membrane of the parasites.
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Affiliation(s)
- Jianmin Fang
- *Department of Cellular Biology, and Center for Tropical and Emerging Global Diseases, The University of Georgia, Athens, GA 30602, U.S.A
| | - Norma Marchesini
- †Laboratory of Molecular Parasitology, Department of Pathobiology and Center for Zoonoses Research, University of Illinois at Urbana-Champaign, Urbana, IL 61802, U.S.A
| | - Silvia N. J. Moreno
- *Department of Cellular Biology, and Center for Tropical and Emerging Global Diseases, The University of Georgia, Athens, GA 30602, U.S.A
- †Laboratory of Molecular Parasitology, Department of Pathobiology and Center for Zoonoses Research, University of Illinois at Urbana-Champaign, Urbana, IL 61802, U.S.A
- To whom correspondence should be addressed (email )
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Krawczyk-Balska A, Bielecki J. Listeria monocytogenes listeriolysin O and phosphatidylinositol-specific phospholipase C affect adherence to epithelial cells. Can J Microbiol 2006; 51:745-51. [PMID: 16391652 DOI: 10.1139/w05-058] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Listeria monocytogenes, a foodborn intracellular animal and human pathogen, produces several exotoxins contributing to virulence. Among these are listeriolysin O (LLO), a pore-forming cholesterol-dependent hemolysin, and a phosphatidylinositol-specific phospholipase C (PI-PLC). LLO is known to play an important role in the escape of bacteria from the primary phagocytic vacuole of macrophages, and PI-PLC supports this process. Evidence is accumulating that LLO and PI-PLC are multifunctional virulence factors with many important roles in the host-parasite interaction other than phagosomal membrane disruption. LLO and PI-PLC may induce a number of host cell responses by modulating signal transduction of infected cells via intracellular Ca2+ levels and the metabolism of phospholipids. This would result in the activation of host phospholipase C and protein kinase C. In the present study, using Bacillus sub tilis strains expressing LLO, PI-PLC, and simultaneously LLO and PI-PLC, we show that LLO and PI-PLC enhance bacterial binding to epithelial cells Int407, with LLO being necessary and PI-PLC playing an accessory role. The results of this work suggest that these two listerial proteins act on epithelial cells prior to internalization.
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Affiliation(s)
- Agata Krawczyk-Balska
- Department of General Microbiology, Institute of Microbiology, University of Warsaw, Poland.
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Wei Z, Schnupf P, Poussin MA, Zenewicz LA, Shen H, Goldfine H. Characterization of Listeria monocytogenes expressing anthrolysin O and phosphatidylinositol-specific phospholipase C from Bacillus anthracis. Infect Immun 2005; 73:6639-46. [PMID: 16177340 PMCID: PMC1230906 DOI: 10.1128/iai.73.10.6639-6646.2005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Two virulence factors of Listeria monocytogenes, listeriolysin O (LLO) and phosphatidylinositol-specific phospholipase C (PI-PLC), mediate escape of this pathogen from the phagocytic vacuole of macrophages, thereby allowing the bacterium access to the host cell cytosol for growth and spread to neighboring cells. We characterized their orthologs from Bacillus anthracis by expressing them in L. monocytogenes and characterizing their contribution to bacterial intracellular growth and cell-to-cell spread. We generated a series of L. monocytogenes strains expressing B. anthracis anthrolysin O (ALO) and PI-PLC in place of LLO and L. monocytogenes PI-PLC, respectively. We found that ALO was active at both acidic and neutral pH and could functionally replace LLO in mediating escape from a primary vacuole; however, ALO exerted a toxic effect on the host cell by damaging the plasma membrane. B. anthracis PI-PLC, unlike the L. monocytogenes ortholog, had high activity on glycosylphosphatidylinositol-anchored proteins. L. monocytogenes expressing B. anthracis PI-PLC showed significantly decreased efficiencies of escape from a phagosome and in cell-to-cell spread. We further compared the level of cytotoxicity to host cells by using mutant strains expressing ALO in combination either with L. monocytogenes PI-PLC or with B. anthracis PI-PLC. The results demonstrated that the mutant strain expressing the combination of ALO and B. anthracis PI-PLC caused less damage to host cells than the strain expressing ALO and L. monocytogenes PI-PLC. The present study indicates that LLO and L. monocytogenes PI-PLC has adapted for L. monocytogenes intracellular growth and virulence and suggests that ALO and B. anthracis PI-PLC may have a role in B. anthracis pathogenesis.
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Affiliation(s)
- Zhengyu Wei
- Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia, 19104-6076, USA
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Pan YY, Wang X, Ma LG, Sun DY. Characterization of phosphatidylinositol-specific phospholipase C (PI-PLC) from Lilium daviddi pollen. Plant Cell Physiol 2005; 46:1657-65. [PMID: 16085656 DOI: 10.1093/pcp/pci181] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The phosphatidylinositol-specific phospholipase C (PI-PLC) activity is detected in purified Lilium pollen protoplasts. Two PI-PLC full length cDNAs, LdPLC1 and LdPLC2, were isolated from pollen of Lilium daviddi. The amino acid sequences for the two PI-PLCs deduced from the two cDNA sequences contain X, Y catalytic motifs and C2 domains. Blast analysis shows that LdPLCs have 60-65% identities to the PI-PLCs from other plant species. Both recombinant PI-PLCs proteins expressed in E. coli cells show the PIP(2)-hydrolyzing activity. The RT-PCR analysis shows that both of them are expressed in pollen grains, whereas expression level of LdPLC2 is induced in germinating pollen. The exogenous purified calmodulin (CaM) is able to stimulate the activity of the PI-PLC when it is added into the pollen protoplast medium, while anti-CaM antibody suppresses the stimulation effect caused by exogenous CaM. PI-PLC activity is enhanced by G protein agonist cholera toxin and decreased by G protein antagonist pertussis toxin. Increasing in PI-PLC activity caused by exogenous purified CaM is also inhibited by pertussis toxin. A PI-PLC inhibitor, U-73122, inhibited the stimulation of PI-PLC activity caused by cholera toxin and it also leads to the decrease of [Ca(2+)](cyt) in pollen grains. Those results suggest that the PPI-PLC signaling pathway is present in Lilium daviddi pollen, and PI-PLC activity might be regulated by a heterotrimeric G protein and extracellular CaM.
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Affiliation(s)
- Yan-Yun Pan
- Institute of Molecular Cell Biology, Hebei Normal University, Shijiazhuang, Hebei, PR China
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Wei Z, Zenewicz LA, Goldfine H. Listeria monocytogenes phosphatidylinositol-specific phospholipase C has evolved for virulence by greatly reduced activity on GPI anchors. Proc Natl Acad Sci U S A 2005; 102:12927-31. [PMID: 16118276 PMCID: PMC1200258 DOI: 10.1073/pnas.0501725102] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Listeria monocytogenes phosphatidylinositol-specific phospholipase C (PI-PLC) plays a critical role in escape of this human pathogen from host cell vacuoles. Unlike classical bacterial PI-PLCs, the L. monocytogenes enzyme has very weak activity on glycosylphosphatidylinositol (GPI)-anchored proteins. Previous crystal structure analysis has revealed that a small beta-strand (Vb) is present in Bacillus cereus PI-PLC and is absent in the enzyme from L. monocytogenes. This Vb beta-strand in B. cereus PI-PLC forms contacts with the glycan linker of GPI anchors, which presumably increases its activity on GPI-anchored proteins. In this study, we show that, of all known bacterial PI-PLCs, those from listeriae are the only ones that lack the beta-strand. Expression by L. monocytogenes of B. cereus PI-PLC, which has strong activity on GPI-anchored proteins, inhibited bacterial escape from a vacuole and cell-to-cell spread, resulting in greatly reduced virulence in mice. Deletion of the Vb beta-strand from B. cereus PI-PLC abolished its ability to cleave GPI-anchored proteins, decreased its inhibitory effects, and increased its virulence in mice. These results strongly suggest that L. monocytogenes PI-PLC has evolved as an important determinant of L. monocytogenes pathogenesis by absence of the Vb beta-strand, thus leading to greatly reduced activity on GPI-anchored proteins.
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Affiliation(s)
- Zhengyu Wei
- Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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Zhai S, Sui Z, Yang A, Zhang J. Characterization of a Novel Phosphoinositide-Specific Phospholipase C from Zea mays and its Expression in Escherichia coli. Biotechnol Lett 2005; 27:799-804. [PMID: 16086263 DOI: 10.1007/s10529-005-5802-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2005] [Revised: 04/08/2005] [Accepted: 04/14/2005] [Indexed: 11/26/2022]
Abstract
A cDNA encoding a phosphoinositide-specific phospholipase C (PI-PLC) has been isolated from Zea mays by screening a cDNA library. The cDNA, designated ZmPLC, encodes a polypeptide of 586 amino acids, containing the catalytic X, Y and C2 domains found in all PI-PLCs from plants. Northern blot analysis showed that the expression of the ZmPLC gene in roots is up-regulated under conditions of high salt, dehydration, cold or low osmotic stress conditions. Recombinant ZmPLC protein was expressed in Esch- erichia coli, purified and used to produce polyclonal antibody, this polyclonal antibody is important for further studies to assess the ultimate function of the ZmPLC gene in plants.
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MESH Headings
- Amino Acid Sequence
- Blotting, Northern
- Cloning, Molecular
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- Electrophoresis, Polyacrylamide Gel
- Escherichia coli/genetics
- Gene Expression Regulation, Enzymologic
- Gene Expression Regulation, Plant
- Immunoblotting
- Molecular Sequence Data
- Phosphatidylinositol Diacylglycerol-Lyase/genetics
- Phosphatidylinositol Diacylglycerol-Lyase/metabolism
- Phosphatidylinositols/metabolism
- Phosphoinositide Phospholipase C
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Recombinant Proteins/biosynthesis
- Recombinant Proteins/isolation & purification
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Type C Phospholipases/genetics
- Type C Phospholipases/metabolism
- Zea mays/enzymology
- Zea mays/genetics
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Affiliation(s)
- Shumei Zhai
- School of Life Science, Shandong University, Jinan, 250100, P.R. China
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Webb H, Burns R, Ellis L, Kimblin N, Carrington M. Developmentally regulated instability of the GPI-PLC mRNA is dependent on a short-lived protein factor. Nucleic Acids Res 2005; 33:1503-12. [PMID: 15755751 PMCID: PMC1062878 DOI: 10.1093/nar/gki298] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The expression of the vast majority of protein coding genes in trypanosomes is regulated exclusively at the post-transcriptional level. Developmentally regulated mRNAs that vary in levels of expression have provided an insight into one mechanism of regulation; a decrease in abundance is due to a shortened mRNA half-life. The decrease in half-life involves cis-acting elements in the 3′ untranslated region of the mRNA. The trans-acting factors necessary for the increased rate of degradation remain uncharacterized. The GPI-PLC gene in Trypanosoma brucei encodes a phospholipase C expressed in mammalian bloodstream form, but not in the insect procyclic form. Here, it is reported that the differential expression of the GPI-PLC mRNA also results from a 10-fold difference in half-life. Second, the instability of the GPI-PLC mRNA in procyclic forms can be reversed by the inhibition of protein synthesis. Third, specifically blocking the translation of the GPI-PLC mRNA in procyclic forms by the inclusion of a hairpin in the 5′ untranslated region does not result in stabilization of the mRNA. Thus, the effect of protein synthesis inhibitors in stabilizing the GPI-PLC mRNA operates in trans through a short-lived factor dependent on protein synthesis.
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Affiliation(s)
| | | | | | | | - Mark Carrington
- To whom correspondence should be addressed. Tel: +44 1223 333683; Fax: +44 1223 766002;
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15
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Okura M, Fang J, Salto ML, Singer RS, Docampo R, Moreno SNJ. A lipid-modified phosphoinositide-specific phospholipase C (TcPI-PLC) is involved in differentiation of trypomastigotes to amastigotes of Trypanosoma cruzi. J Biol Chem 2005; 280:16235-43. [PMID: 15710612 DOI: 10.1074/jbc.m414535200] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The phosphoinositide-specific phospholipase C (PI-PLC) is an important component of the inositol phosphate/diacylglycerol signaling pathway. A newly discovered Trypanosoma cruzi PI-PLC (TcPI-PLC) is lipid modified in its N terminus, targeted to its plasma membrane, and believed to play a role in differentiation of the parasite because its expression increases during the differentiation of trypomastigote to amastigote stages. To determine whether TcPI-PLC is involved in this differentiation step, antisense inhibition using phosphorothioate-modified oligonucleotides, and overexpression of the gene were performed. Antisense oligonucleotide-treated parasites showed a reduced rate of differentiation in comparison to controls, as well as accumulation of intermediate forms. Overexpression of TcPI-PLC led to a faster differentiation rate. In contrast, overexpression of a mutant TcPI-PLC that lacked the lipid modification at its N terminus did not affect the differentiation rate. Therefore, TcPI-PLC is involved, when expressed in the plasma membrane, in the differentiation of trypomastigotes to amastigotes, an essential step for the intracellular replication of these parasites.
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Affiliation(s)
- Michael Okura
- Department of Pathobiology and Center for Zoonoses Research, University of Illinois at Urbana-Champaign, Urbana, Illinois 61802, USA
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16
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Stewart AJ, Mukherjee J, Roberts SJ, Lester D, Farquharson C. Identification of a novel class of mammalian phosphoinositol-specific phospholipase C enzymes. Int J Mol Med 2005; 15:117-21. [PMID: 15583837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023] Open
Abstract
Phosphoinositol (PhoIns)-specific phospholipase C enzymes (PLCs) are central to the inositol lipid signaling pathways and contribute to intracellular Ca2+ release and protein kinase C activation. Five distinct classes of PhoIns-specific PLCs are known to exist in mammals, which are activated by membrane receptor-mediated events. Here we have identified a sixth class of PhoIns-specific PLC with a novel domain structure, which we have termed PLC-eta. Two putative PLC-eta enzymes were identified in humans and in mice. Sequence analysis revealed that residues implicated in substrate binding and catalysis from other PhoIns-specific PLCs are conserved in the novel enzymes. PLC-eta enzymes are most closely related to the PLC-delta class and share a close evolutionary relationship with other PLC isozymes. EST analysis and RT-PCR data suggest that PLC-eta enzymes are expressed in several cell types and, by analogy with other mammalian PhoIns-specific PLCs, are likely to be involved in signal transduction pathways.
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Affiliation(s)
- Alan J Stewart
- Division of Gene Function and Development, Roslin Institute, Roslin, Midlothian EH25 9PS, UK.
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17
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Repp A, Mikami K, Mittmann F, Hartmann E. Phosphoinositide-specific phospholipase C is involved in cytokinin and gravity responses in the moss Physcomitrella patens. Plant J 2004; 40:250-9. [PMID: 15447651 DOI: 10.1111/j.1365-313x.2004.02205.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The phosphoinositide signalling pathway is important in plant responses to extracellular and intracellular signals. To elucidate the physiological functions of phosphoinositide-specific phopspholipase C, PI-PLC, targeted knockout mutants of PpPLC1, a gene encoding a PI-PLC from the moss Physcomitrella patens, were generated via homologous recombination. Protonemal filaments of the plc1 lines show a dramatic reduction in gametophore formation relative to wild type: this was accompanied by a loss of sensitivity to cytokinin. Moreover, plc1 appeared paler than the wild type, the result of an altered differentiation of chloroplasts and reduced chlorophyll levels compared with wild type filaments. In addition, the protonemal filaments of plc1 have a strongly reduced ability to grow negatively gravitropically in the dark. These effects imply a significant role for PpPLC1 in cytokinin signalling and gravitropism.
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Affiliation(s)
- Alexander Repp
- Institut für Biologie--Pflanzenphysiologie, Freie Universität Berlin, Königin-Luise-Str. 12-16, 14195 Berlin, Germany
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18
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Wichroski MJ, Ward GE. Biosynthesis of glycosylphosphatidylinositol is essential to the survival of the protozoan parasite Toxoplasma gondii. Eukaryot Cell 2004; 2:1132-6. [PMID: 14555496 PMCID: PMC219362 DOI: 10.1128/ec.2.5.1132-1136.2003] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The PIGA gene from Toxoplasma gondii has been cloned and characterized. Like mammalian PIGA, the transmembrane and C-terminal domains are sufficient to direct localization to the parasite endoplasmic reticulum. A functional copy of PIGA is required for tachyzoite viability, demonstrating that glycosylphosphatidylinositol biosynthesis is an essential process in T. gondii.
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Affiliation(s)
- Michael J Wichroski
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405, USA
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Mikami K, Repp A, Graebe-Abts E, Hartmann E. Isolation of cDNAs encoding typical and novel types of phosphoinositide-specific phospholipase C from the moss Physcomitrella patens. J Exp Bot 2004; 55:1437-9. [PMID: 15073208 DOI: 10.1093/jxb/erh140] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Two cDNAs encoding proteins, PpPLC1 and PpPLC2, with catalytic and C2 domains conserved in plant phosphoinositide-specific phospholipase C (PI-PLC) were isolated from Physcomitrella patens. The N domain, which has been identified in Arabidopsis PI-PLCs as an EF hand-like domain, was found in both isoforms, although that in PpPLC2 was a split type. At micromolar Ca2+ concentrations, PpPLC1 preferentially hydrolysed phosphatidylinositol-4,5-bisphosphate, while PpPLC2 showed no specificity. Furthermore, at millimolar Ca2+, phosphatidylinositol was hydrolysed by PpPLC2, but not by PpPLC1. Thus, PpPLC1 and PpPLC2 are typical and novel types of plant PI-PLC, respectively.
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Affiliation(s)
- Koji Mikami
- National Institute for Basic Biology, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Japan.
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20
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Kim YJ, Kim JE, Lee JH, Lee MH, Jung HW, Bahk YY, Hwang BK, Hwang I, Kim WT. The Vr-PLC3 gene encodes a putative plasma membrane-localized phosphoinositide-specific phospholipase C whose expression is induced by abiotic stress in mung bean (Vigna radiata L.). FEBS Lett 2004; 556:127-36. [PMID: 14706839 DOI: 10.1016/s0014-5793(03)01388-7] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Phosphoinositide-specific phospholipase C (PI-PLC) catalyzes the hydrolysis of phosphatidylinositol 4,5-bisphosphate to generate inositol 1,4,5-trisphosphate and diacylglycerol, both of which act as secondary messengers in animal cells. In this report, we identified in Vigna radiata L. (mung bean) three distinct partial cDNAs (pVr-PLC1, pVr-PLC2, and pVr-PLC3), which encode forms of putative PI-PLC. All three Vr-PLC genes were transcriptionally active and displayed unique patterns of expression. The Vr-PLC1 and Vr-PLC2 transcripts were constitutively expressed to varying degrees in every tissue of mung bean plants examined. In contrast, the Vr-PLC3 mRNA level was very low under normal growth conditions and was rapidly induced in an abscisic acid-independent manner under environmental stress conditions (drought and high salinity). An isolated genomic clone, about 8.2 kb in length, showed that Vr-PLC1 and Vr-PLC3 are in tandem array in the mung bean genome. The predicted primary sequence of Vr-PLC3 (M(r)=67.4 kDa) is reminiscent of the delta-isoform of animal enzymes which contain core sequences found in typical PI-PLCs, such as the catalytic domain comprising X and Y motifs, a lipid-binding C2 domain, and the less conserved EF-hand domain. Results of in vivo targeting experiment using a green fluorescent protein (GFP) showed that the GFP-Vr-PLC3 fusion protein was localized primarily to the plasma membrane of the Arabidopsis protoplast. The C2 domain was essential for Vr-PLC3 to be targeted to the plasma membrane. The possible biological functions of stress-responsive Vr-PLC3 in mung bean plants are discussed.
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Affiliation(s)
- Yun Ju Kim
- Department of Biology, College of Science, Yonsei University, 120-749, Seoul, South Korea
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21
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Feng J, Stieglitz K, Roberts MF. Mutation of Two Active-Site Residues Converts a Phosphatidylinositol-Specific Phospholipase C to a Glucose Phosphatase. J Am Chem Soc 2004; 126:1008-9. [PMID: 14746454 DOI: 10.1021/ja038529u] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Two mutations, R69D and K115E, converted a bacterial phosphatidylinositol-specific phospholipase C (PI-PLC) to a phosphatase with much higher specific activity toward glucose-6-phosphate than inositol-1-phosphate. PI-PLC single mutations R69D and K115E can cleave PI but lack any demonstrable phosphatase activity. The bacterial PI-PLC has no sequence homology with known glucose-6-phosphatase enzymes, which need His, Arg, and negatively charged residues (Asp or Glu) at the active site. The change in chemical reaction and substrate specificity can be rationalized by energy minimization of the mutant with I-1-P or G-6-P bound.
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Affiliation(s)
- Jianwen Feng
- Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, USA
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