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Garten M, Kachman MM, Glushakova S, Zimmerberg J. Calcium-Activated Potassium Channels in the Malaria Parasite Erythrocyte Cycle. Biophys J 2016. [DOI: 10.1016/j.bpj.2015.11.2407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Wirth CC, Glushakova S, Scheuermayer M, Repnik U, Garg S, Schaack D, Kachman MM, Weißbach T, Zimmerberg J, Dandekar T, Griffiths G, Chitnis CE, Singh S, Fischer R, Pradel G. Perforin-like protein PPLP2 permeabilizes the red blood cell membrane during egress of Plasmodium falciparum gametocytes. Cell Microbiol 2014; 16:709-33. [PMID: 24602217 PMCID: PMC4312913 DOI: 10.1111/cmi.12288] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 02/17/2014] [Accepted: 02/21/2014] [Indexed: 12/18/2022]
Abstract
Egress of malaria parasites from the host cell requires the concerted rupture of its enveloping membranes. Hence, we investigated the role of the plasmodial perforin-like protein PPLP2 in the egress of Plasmodium falciparum from erythrocytes. PPLP2 is expressed in blood stage schizonts and mature gametocytes. The protein localizes in vesicular structures, which in activated gametocytes discharge PPLP2 in a calcium-dependent manner. PPLP2 comprises a MACPF domain and recombinant PPLP2 has haemolytic activities towards erythrocytes. PPLP2-deficient [PPLP2(−)] merozoites show normal egress dynamics during the erythrocytic replication cycle, but activated PPLP2(−) gametocytes were unable to leave erythrocytes and stayed trapped within these cells. While the parasitophorous vacuole membrane ruptured normally, the activated PPLP2(−) gametocytes were unable to permeabilize the erythrocyte membrane and to release the erythrocyte cytoplasm. In consequence, transmission of PPLP2(−) parasites to the Anopheles vector was reduced. Pore-forming equinatoxin II rescued both PPLP2(−) gametocyte exflagellation and parasite transmission. The pore sealant Tetronic 90R4, on the other hand, caused trapping of activated wild-type gametocytes within the enveloping erythrocytes, thus mimicking the PPLP2(−) loss-of-function phenotype. We propose that the haemolytic activity of PPLP2 is essential for gametocyte egress due to permeabilization of the erythrocyte membrane and depletion of the erythrocyte cytoplasm.
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Affiliation(s)
- Christine C Wirth
- Institute of Molecular Biotechnology, RWTH Aachen University, Worringerweg 1, 52074, Aachen, Germany
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Eun B, Sampley ML, Van Winkle MT, Good AL, Kachman MM, Pfeifer K. The Igf2/H19 muscle enhancer is an active transcriptional complex. Nucleic Acids Res 2013; 41:8126-34. [PMID: 23842673 PMCID: PMC3783178 DOI: 10.1093/nar/gkt597] [Citation(s) in RCA: 18] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 06/13/2013] [Accepted: 06/15/2013] [Indexed: 02/06/2023] Open
Abstract
In eukaryotic cells, gene expression is mediated by enhancer activation of RNA polymerase at distant promoters. Recently, distinctions between enhancers and promoters have been blurred by the discovery that enhancers are associated with RNA polymerase and are sites of RNA synthesis. Here, we present an analysis of the insulin-like growth factor 2/H19 muscle enhancer. This enhancer includes a short conserved core element that is organized into chromatin typical of mammalian enhancers, binds tissue-specific transcription factors and functions on its own in vitro to activate promoter transcription. However, in a chromosomal context, this element is not sufficient to activate distant promoters. Instead, enhancer function also requires transcription in cis of a long non-coding RNA, Nctc1. Thus, the insulin-like growth factor 2/H19 enhancer is an active transcriptional complex whose own transcription is essential to its function.
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Affiliation(s)
- Bokkee Eun
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA and Core-Laboratory, College of Medicine, Korea University, Seoul 136-701, Republic of Korea
| | - Megan L. Sampley
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA and Core-Laboratory, College of Medicine, Korea University, Seoul 136-701, Republic of Korea
| | - Matthew T. Van Winkle
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA and Core-Laboratory, College of Medicine, Korea University, Seoul 136-701, Republic of Korea
| | - Austin L. Good
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA and Core-Laboratory, College of Medicine, Korea University, Seoul 136-701, Republic of Korea
| | - Marika M. Kachman
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA and Core-Laboratory, College of Medicine, Korea University, Seoul 136-701, Republic of Korea
| | - Karl Pfeifer
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA and Core-Laboratory, College of Medicine, Korea University, Seoul 136-701, Republic of Korea
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