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Papers by Christian Doerig

Research paper thumbnail of Inhibition of the SR Protein-Phosphorylating CLK Kinases of Plasmodium falciparum Impairs Blood Stage Replication and Malaria Transmission

Research paper thumbnail of An evolutionary perspective on the kinome of malaria parasites

Philosophical Transactions of the Royal Society B, Sep 19, 2012

Research paper thumbnail of PAK in pathogen-host interactions

Cellular logistics, Apr 1, 2012

Research paper thumbnail of Protein kinases of malaria parasites: an update

Trends in Parasitology, Dec 1, 2008

Research paper thumbnail of Signalome-wide assessment of erythrocyte response to Plasmodium reveals novel targets for host-directed antimalarial intervention

Research paper thumbnail of Plasmodium falciparum Regulatory Subunit of cAMP-Dependent PKA and Anion Channel Conductance

PLOS Pathogens, Feb 1, 2008

Research paper thumbnail of PI4‐kinase and PfCDPK7 signaling regulate phospholipid biosynthesis in Plasmodium falciparum

EMBO reports, 2021

PfCDPK7 is an atypical member of the calcium‐dependent protein kinase (CDPK) family and is crucia... more PfCDPK7 is an atypical member of the calcium‐dependent protein kinase (CDPK) family and is crucial for the development of Plasmodium falciparum. However, the mechanisms whereby PfCDPK7 regulates parasite development remain unknown. Here, we perform quantitative phosphoproteomics and phospholipid analysis and find that PfCDPK7 promotes phosphatidylcholine (PC) synthesis by regulating two key enzymes involved in PC synthesis, phosphoethanolamine‐N‐methyltransferase (PMT) and ethanolamine kinase (EK). In the absence of PfCDPK7, both enzymes are hypophosphorylated and PMT is degraded. We further find that PfCDPK7 interacts with 4'‐phosphorylated phosphoinositides (PIPs) generated by PI4‐kinase. Inhibition of PI4K activity disrupts the vesicular localization PfCDPK7. P. falciparum PI4‐kinase, PfPI4K is a prominent drug target and one of its inhibitors, MMV39048, has reached Phase I clinical trials. Using this inhibitor, we demonstrate that PfPI4K controls phospholipid biosynthesis and may act in part by regulating PfCDPK7 localization and activity. These studies not only unravel a signaling pathway involving PfPI4K/4'‐PIPs and PfCDPK7 but also provide novel insights into the mechanism of action of a promising series of candidate anti‐malarial drugs.

Research paper thumbnail of IBMX Stimulation of Membrane Anion Conductance of pfpka-r Transformed Parasites

Research paper thumbnail of Parasite and Host Erythrocyte Kinomics of Plasmodium Infection

Trends in Parasitology, 2021

Malaria remains a heavy public health and socioeconomic burden in tropical and subtropical region... more Malaria remains a heavy public health and socioeconomic burden in tropical and subtropical regions. Increasing resistance against front-line treatments implies that novel targets for antimalarial intervention are urgently required. Protein kinases of both the parasites and their host cells possess strong potential in this respect. We present an overview of the updated kinome of Plasmodium falciparum, the species that is the largest contributor to malaria mortality, and of current knowledge pertaining to the function of parasite-encoded protein kinases during the parasite's life cycle. Furthermore, we detail recent advances in drug initiatives targeting Plasmodium kinases and outline the potential of protein kinases in the context of the growing field of host-directed therapies, which is currently being explored as a novel way to combat parasite drug resistance.

Research paper thumbnail of GDV1 C-terminal truncation of 39 amino acids disrupts sexual commitment in Plasmodium falciparum

Malaria is a mosquito-borne disease caused by apicomplexan parasites of the genus Plasmodium. Com... more Malaria is a mosquito-borne disease caused by apicomplexan parasites of the genus Plasmodium. Completion of the parasite’s life cycle depends on the transmission of sexual stages, the gametocytes, from an infected human host to the mosquito vector. Sexual commitment occurs in only a small fraction of asexual blood stage parasites and is initiated by external cues. The gametocyte development protein 1 (GDV1) has been described as a key facilitator to trigger sexual commitment. GDV1 interacts with the silencing factor heterochromatin protein 1 (HP1), leading to its dissociation from heterochromatic DNA at the genomic locus encoding AP2-G, the master transcription factor of gametocytogenesis. How this process is regulated is not known. In this study we have addressed the role of protein kinases implicated in gametocyte development. From a pool of available protein kinase KO lines, we identified two kinase knockout lines which fail to produce gametocytes. However, independent genetic ve...

Research paper thumbnail of A 39-Amino-Acid C-Terminal Truncation of GDV1 Disrupts Sexual Commitment in Plasmodium falciparum

mSphere, 2021

Transmission of malaria-causing Plasmodium species by mosquitos requires the parasite to change f... more Transmission of malaria-causing Plasmodium species by mosquitos requires the parasite to change from a continuously growing asexual parasite form growing in the blood to a sexually differentiated form, the gametocyte. Only a small subset of asexual parasites differentiates into gametocytes that are taken up by the mosquito.

Research paper thumbnail of Inhibition of Resistance-Refractory P. falciparum Kinase PKG Delivers Prophylactic, Blood Stage, and Transmission-Blocking Antiplasmodial Activity

Cell Chemical Biology, 2020

Highlights d MMV030084 inhibits P. falciparum liver and asexual blood stages and male gametes d P... more Highlights d MMV030084 inhibits P. falciparum liver and asexual blood stages and male gametes d Proteomic and conditional knockdown studies identified PfPKG as the target d Resistance selection studies identified TKL3 as a low-level resistance mediator d PKG is a promising resistance-refractory target for antimalarial drug development

Research paper thumbnail of Nonstructural protein of parvoviruses B19 and minute virus of mice controls transcription

Journal of Virology, 1990

The genome of the human parvovirus B19 contains a transcriptional promoter (BP06) at map position... more The genome of the human parvovirus B19 contains a transcriptional promoter (BP06) at map position 6, upstream from the nonstructural protein genes. By cotransfecting HeLa cells with this promoter cloned before the chloramphenicol acetyltransferase (CAT) gene together with a plasmid containing almost the whole B19 genome, we showed that BP06 is transactivated by a B19 gene product. The transactivating viral protein was identified as the nonstructural protein NS-1. NS-1 synthesized in a wheat germ extract specifically stimulates transcription from BP06 in vitro. NS-1 of the minute virus of mice (MVM) activates the analogous MVM promoter, MP04. NS-1, therefore, has a positive feedback effect on the activity of its own promoter. Moreover, NS-1 of MVM activates the human BP06. We have identified, in the genome of B19, a second transcriptional promoter activity at map position 44, before the capsid protein genes. This promoter, BP44, was identified by cloning fragments of B19 DNA upstream...

Research paper thumbnail of Nucleoprotein complexes of minute virus of mice have a distinct structure different from that of chromatin

Journal of Virology, 1986

We studied the structure of viral nucleoprotein complexes extracted from the nuclei of mouse cell... more We studied the structure of viral nucleoprotein complexes extracted from the nuclei of mouse cells infected with the immunosuppressive strain of the minute virus of mice (MVMi). Two types of complex were detected, with sedimentation coefficients of about 110 and 40S. The complexes sedimenting at 110S contained single-stranded MVMi DNA as well as a second form of viral DNA which apparently had a heat-sensitive secondary structure. The 110S peak also contained proteins which coelectrophoresed with the MVMi capsid proteins. Complexes sedimenting at 40S contained the double-stranded replicative form of MVMi DNA. These complexes sedimented faster than did the pure replicative form DNA (15S), but more slowly than cellular chromatin fragments containing DNA of the same length. They incorporated labeled deoxynucleoside triphosphate in vitro into the replicative form DNA. We investigated the structure of MVMi nucleoprotein complexes in the following ways. Nuclei of MVMi-infected cells were d...

Research paper thumbnail of Phosphorylation of the VAR2CSA extracellular region is associated with enhanced adhesive properties to the placental receptor CSA

Research paper thumbnail of Structure of P. falciparum PfPK5-Indirubin-5-sulphonate ligand complex

Research paper thumbnail of Crystal structure of the t198a mutant of pfpk5

Research paper thumbnail of Structure of P. falciparum PfPK5

Research paper thumbnail of A NIMA-related Protein Kinase Is Essential for Completion of the Sexual Cycle of Malaria Parasites

Journal of Biological Chemistry, 2005

The molecular mechanisms regulating the sexual development of malaria parasites from gametocytes ... more The molecular mechanisms regulating the sexual development of malaria parasites from gametocytes to oocysts in their mosquito vector are still largely unexplored. In other eukaryotes, NIMA-related kinases (Neks) regulate cell cycle progression and have been implicated in the regulation of meiosis. Here, we demonstrate that Nek-4, a new Plasmodium member of the Nek family, is essential for completion of the sexual cycle of the parasite. Recombinant Plasmodium falciparum Nek-4 possesses protein kinase activity and displays substrate preferences similar to those of other Neks. Nek-4 is highly expressed in gametocytes, yet disruption of the nek-4 gene in the rodent malaria parasite P. berghei has no effect on gamete formation and subsequent fertilization. However, further differentiation of zygotes into ookinetes is abolished. Measurements of nuclear DNA content indicate that zygotes lacking Nek-4 fail to undergo the genome replication to the tetraploid level that precedes meiosis. Cell cycle progression in the zygote is identified as a likely precondition for its morphological transition to the ookinete and for the successful establishment of a malaria infection in the mosquito.

Research paper thumbnail of THE P. falciparum CDK FAMILY: STRUCTURAL STUDIES AND IMPLICATIONS FOR INHIBITOR DESIGN

aseanbiotechnology.info

The P. falciparum life cycle is complex and deviates from the classical eukaryotic mitotic cell c... more The P. falciparum life cycle is complex and deviates from the classical eukaryotic mitotic cell cycle where DNA replication is closely tied to subsequent cell division. Understanding the molecular switches that control this unusual developmental cycle would benefit both ...

Research paper thumbnail of Inhibition of the SR Protein-Phosphorylating CLK Kinases of Plasmodium falciparum Impairs Blood Stage Replication and Malaria Transmission

Research paper thumbnail of An evolutionary perspective on the kinome of malaria parasites

Philosophical Transactions of the Royal Society B, Sep 19, 2012

Research paper thumbnail of PAK in pathogen-host interactions

Cellular logistics, Apr 1, 2012

Research paper thumbnail of Protein kinases of malaria parasites: an update

Trends in Parasitology, Dec 1, 2008

Research paper thumbnail of Signalome-wide assessment of erythrocyte response to Plasmodium reveals novel targets for host-directed antimalarial intervention

Research paper thumbnail of Plasmodium falciparum Regulatory Subunit of cAMP-Dependent PKA and Anion Channel Conductance

PLOS Pathogens, Feb 1, 2008

Research paper thumbnail of PI4‐kinase and PfCDPK7 signaling regulate phospholipid biosynthesis in Plasmodium falciparum

EMBO reports, 2021

PfCDPK7 is an atypical member of the calcium‐dependent protein kinase (CDPK) family and is crucia... more PfCDPK7 is an atypical member of the calcium‐dependent protein kinase (CDPK) family and is crucial for the development of Plasmodium falciparum. However, the mechanisms whereby PfCDPK7 regulates parasite development remain unknown. Here, we perform quantitative phosphoproteomics and phospholipid analysis and find that PfCDPK7 promotes phosphatidylcholine (PC) synthesis by regulating two key enzymes involved in PC synthesis, phosphoethanolamine‐N‐methyltransferase (PMT) and ethanolamine kinase (EK). In the absence of PfCDPK7, both enzymes are hypophosphorylated and PMT is degraded. We further find that PfCDPK7 interacts with 4'‐phosphorylated phosphoinositides (PIPs) generated by PI4‐kinase. Inhibition of PI4K activity disrupts the vesicular localization PfCDPK7. P. falciparum PI4‐kinase, PfPI4K is a prominent drug target and one of its inhibitors, MMV39048, has reached Phase I clinical trials. Using this inhibitor, we demonstrate that PfPI4K controls phospholipid biosynthesis and may act in part by regulating PfCDPK7 localization and activity. These studies not only unravel a signaling pathway involving PfPI4K/4'‐PIPs and PfCDPK7 but also provide novel insights into the mechanism of action of a promising series of candidate anti‐malarial drugs.

Research paper thumbnail of IBMX Stimulation of Membrane Anion Conductance of pfpka-r Transformed Parasites

Research paper thumbnail of Parasite and Host Erythrocyte Kinomics of Plasmodium Infection

Trends in Parasitology, 2021

Malaria remains a heavy public health and socioeconomic burden in tropical and subtropical region... more Malaria remains a heavy public health and socioeconomic burden in tropical and subtropical regions. Increasing resistance against front-line treatments implies that novel targets for antimalarial intervention are urgently required. Protein kinases of both the parasites and their host cells possess strong potential in this respect. We present an overview of the updated kinome of Plasmodium falciparum, the species that is the largest contributor to malaria mortality, and of current knowledge pertaining to the function of parasite-encoded protein kinases during the parasite's life cycle. Furthermore, we detail recent advances in drug initiatives targeting Plasmodium kinases and outline the potential of protein kinases in the context of the growing field of host-directed therapies, which is currently being explored as a novel way to combat parasite drug resistance.

Research paper thumbnail of GDV1 C-terminal truncation of 39 amino acids disrupts sexual commitment in Plasmodium falciparum

Malaria is a mosquito-borne disease caused by apicomplexan parasites of the genus Plasmodium. Com... more Malaria is a mosquito-borne disease caused by apicomplexan parasites of the genus Plasmodium. Completion of the parasite’s life cycle depends on the transmission of sexual stages, the gametocytes, from an infected human host to the mosquito vector. Sexual commitment occurs in only a small fraction of asexual blood stage parasites and is initiated by external cues. The gametocyte development protein 1 (GDV1) has been described as a key facilitator to trigger sexual commitment. GDV1 interacts with the silencing factor heterochromatin protein 1 (HP1), leading to its dissociation from heterochromatic DNA at the genomic locus encoding AP2-G, the master transcription factor of gametocytogenesis. How this process is regulated is not known. In this study we have addressed the role of protein kinases implicated in gametocyte development. From a pool of available protein kinase KO lines, we identified two kinase knockout lines which fail to produce gametocytes. However, independent genetic ve...

Research paper thumbnail of A 39-Amino-Acid C-Terminal Truncation of GDV1 Disrupts Sexual Commitment in Plasmodium falciparum

mSphere, 2021

Transmission of malaria-causing Plasmodium species by mosquitos requires the parasite to change f... more Transmission of malaria-causing Plasmodium species by mosquitos requires the parasite to change from a continuously growing asexual parasite form growing in the blood to a sexually differentiated form, the gametocyte. Only a small subset of asexual parasites differentiates into gametocytes that are taken up by the mosquito.

Research paper thumbnail of Inhibition of Resistance-Refractory P. falciparum Kinase PKG Delivers Prophylactic, Blood Stage, and Transmission-Blocking Antiplasmodial Activity

Cell Chemical Biology, 2020

Highlights d MMV030084 inhibits P. falciparum liver and asexual blood stages and male gametes d P... more Highlights d MMV030084 inhibits P. falciparum liver and asexual blood stages and male gametes d Proteomic and conditional knockdown studies identified PfPKG as the target d Resistance selection studies identified TKL3 as a low-level resistance mediator d PKG is a promising resistance-refractory target for antimalarial drug development

Research paper thumbnail of Nonstructural protein of parvoviruses B19 and minute virus of mice controls transcription

Journal of Virology, 1990

The genome of the human parvovirus B19 contains a transcriptional promoter (BP06) at map position... more The genome of the human parvovirus B19 contains a transcriptional promoter (BP06) at map position 6, upstream from the nonstructural protein genes. By cotransfecting HeLa cells with this promoter cloned before the chloramphenicol acetyltransferase (CAT) gene together with a plasmid containing almost the whole B19 genome, we showed that BP06 is transactivated by a B19 gene product. The transactivating viral protein was identified as the nonstructural protein NS-1. NS-1 synthesized in a wheat germ extract specifically stimulates transcription from BP06 in vitro. NS-1 of the minute virus of mice (MVM) activates the analogous MVM promoter, MP04. NS-1, therefore, has a positive feedback effect on the activity of its own promoter. Moreover, NS-1 of MVM activates the human BP06. We have identified, in the genome of B19, a second transcriptional promoter activity at map position 44, before the capsid protein genes. This promoter, BP44, was identified by cloning fragments of B19 DNA upstream...

Research paper thumbnail of Nucleoprotein complexes of minute virus of mice have a distinct structure different from that of chromatin

Journal of Virology, 1986

We studied the structure of viral nucleoprotein complexes extracted from the nuclei of mouse cell... more We studied the structure of viral nucleoprotein complexes extracted from the nuclei of mouse cells infected with the immunosuppressive strain of the minute virus of mice (MVMi). Two types of complex were detected, with sedimentation coefficients of about 110 and 40S. The complexes sedimenting at 110S contained single-stranded MVMi DNA as well as a second form of viral DNA which apparently had a heat-sensitive secondary structure. The 110S peak also contained proteins which coelectrophoresed with the MVMi capsid proteins. Complexes sedimenting at 40S contained the double-stranded replicative form of MVMi DNA. These complexes sedimented faster than did the pure replicative form DNA (15S), but more slowly than cellular chromatin fragments containing DNA of the same length. They incorporated labeled deoxynucleoside triphosphate in vitro into the replicative form DNA. We investigated the structure of MVMi nucleoprotein complexes in the following ways. Nuclei of MVMi-infected cells were d...

Research paper thumbnail of Phosphorylation of the VAR2CSA extracellular region is associated with enhanced adhesive properties to the placental receptor CSA

Research paper thumbnail of Structure of P. falciparum PfPK5-Indirubin-5-sulphonate ligand complex

Research paper thumbnail of Crystal structure of the t198a mutant of pfpk5

Research paper thumbnail of Structure of P. falciparum PfPK5

Research paper thumbnail of A NIMA-related Protein Kinase Is Essential for Completion of the Sexual Cycle of Malaria Parasites

Journal of Biological Chemistry, 2005

The molecular mechanisms regulating the sexual development of malaria parasites from gametocytes ... more The molecular mechanisms regulating the sexual development of malaria parasites from gametocytes to oocysts in their mosquito vector are still largely unexplored. In other eukaryotes, NIMA-related kinases (Neks) regulate cell cycle progression and have been implicated in the regulation of meiosis. Here, we demonstrate that Nek-4, a new Plasmodium member of the Nek family, is essential for completion of the sexual cycle of the parasite. Recombinant Plasmodium falciparum Nek-4 possesses protein kinase activity and displays substrate preferences similar to those of other Neks. Nek-4 is highly expressed in gametocytes, yet disruption of the nek-4 gene in the rodent malaria parasite P. berghei has no effect on gamete formation and subsequent fertilization. However, further differentiation of zygotes into ookinetes is abolished. Measurements of nuclear DNA content indicate that zygotes lacking Nek-4 fail to undergo the genome replication to the tetraploid level that precedes meiosis. Cell cycle progression in the zygote is identified as a likely precondition for its morphological transition to the ookinete and for the successful establishment of a malaria infection in the mosquito.

Research paper thumbnail of THE P. falciparum CDK FAMILY: STRUCTURAL STUDIES AND IMPLICATIONS FOR INHIBITOR DESIGN

aseanbiotechnology.info

The P. falciparum life cycle is complex and deviates from the classical eukaryotic mitotic cell c... more The P. falciparum life cycle is complex and deviates from the classical eukaryotic mitotic cell cycle where DNA replication is closely tied to subsequent cell division. Understanding the molecular switches that control this unusual developmental cycle would benefit both ...