| 1. |
- Russell, Andrew J.C., et al.
(författare)
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Regulators of male and female sexual development are critical for the transmission of a malaria parasite
- 2023
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Ingår i: Cell Host and Microbe. - : Cell Press. - 1931-3128 .- 1934-6069. ; 31:2, s. 305-319.e10
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Tidskriftsartikel (refereegranskat)abstract
- Malaria transmission to mosquitoes requires a developmental switch in asexually dividing blood-stage parasites to sexual reproduction. In Plasmodium berghei, the transcription factor AP2-G is required and sufficient for this switch, but how a particular sex is determined in a haploid parasite remains unknown. Using a global screen of barcoded mutants, we here identify genes essential for the formation of either male or female sexual forms and validate their importance for transmission. High-resolution single-cell transcriptomics of ten mutant parasites portrays the developmental bifurcation and reveals a regulatory cascade of putative gene functions in the determination and subsequent differentiation of each sex. A male-determining gene with a LOTUS/OST-HTH domain as well as the protein interactors of a female-determining zinc-finger protein indicate that germ-granule-like ribonucleoprotein complexes complement transcriptional processes in the regulation of both male and female development of a malaria parasite.
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| 2. |
- Mazza, Tiziano, et al.
(författare)
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Structural basis for the modulation of MRP2 activity by phosphorylation and drugs
- 2024
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Ingår i: Nature Communications. - 2041-1723. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- Multidrug resistance-associated protein 2 (MRP2/ABCC2) is a polyspecific efflux transporter of organic anions expressed in hepatocyte canalicular membranes. MRP2 dysfunction, in Dubin-Johnson syndrome or by off-target inhibition, for example by the uricosuric drug probenecid, elevates circulating bilirubin glucuronide and is a cause of jaundice. Here, we determine the cryo-EM structure of rat Mrp2 (rMrp2) in an autoinhibited state and in complex with probenecid. The autoinhibited state exhibits an unusual conformation for this class of transporter in which the regulatory domain is folded within the transmembrane domain cavity. In vitro phosphorylation, mass spectrometry and transport assays show that phosphorylation of the regulatory domain relieves this autoinhibition and enhances rMrp2 transport activity. The in vitro data is confirmed in human hepatocyte-like cells, in which inhibition of endogenous kinases also reduces human MRP2 transport activity. The drug-bound state reveals two probenecid binding sites that suggest a dynamic interplay with autoinhibition. Mapping of the Dubin-Johnson mutations onto the rodent structure indicates that many may interfere with the transition between conformational states. The ABC transporter MRP2/ABCC2 is a polyspecific efflux transporter of organic anions expressed in hepatocyte canalicular membranes. Dysfunction leads to Dubin-Johnson syndrome. Here the authors provide structural and biochemical evidence on the modulation of MRP2 by intracellular kinases and inhibition by therapeutic drugs.
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| 3. |
- Hillier, Charles, et al.
(författare)
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Landscape of the Plasmodium Interactome Reveals Both Conserved and Species-Specific Functionality
- 2019
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Ingår i: Cell Reports. - : Elsevier. - 2211-1247. ; 28:6, s. 1635-1647
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Tidskriftsartikel (refereegranskat)abstract
- Malaria represents a major global health issue, and the identification of new intervention targets remains an urgent priority. This search is hampered by more than one-third of the genes of malaria-causing Plasmodium parasites being uncharacterized. We report a large-scale protein interaction network in Plasmodium schizonts, generated by combining blue native-polyacrylamide electrophoresis with quantitative mass spectrometry and machine learning. This integrative approach, spanning 3 species, identifies > 20,000 putative protein interactions, organized into 600 protein clusters. We validate selected interactions, assigning functions in chromatin regulation to previously unannotated proteins and suggesting a role for an EELM2 domain-containing protein and a putative microrchidia protein as mechanistic links between AP2-domain transcription factors and epigenetic regulation. Our interactome represents a high-confidence map of the native organization of core cellular processes in Plasmodium parasites. The network reveals putative functions for uncharacterized proteins, provides mechanistic and structural insight, and uncovers potential alternative therapeutic targets.
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| 4. |
- Sebastian, Sarah, et al.
(författare)
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A Plasmodium calcium-dependent protein kinase controls zygote development and transmission by translationally activating repressed mRNAs
- 2012
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Ingår i: Cell Host and Microbe. - : Elsevier. - 1931-3128 .- 1934-6069. ; 12:1, s. 9-19
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Tidskriftsartikel (refereegranskat)abstract
- Calcium-dependent protein kinases (CDPKs) play key regulatory roles in the life cycle of the malaria parasite, but in many cases their precise molecular functions are unknown. Using the rodent malaria parasite Plasmodium berghei, we show that CDPK1, which is known to be essential in the asexual blood stage of the parasite, is expressed in all life stages and is indispensable during the sexual mosquito life-cycle stages. Knockdown of CDPK1 in sexual stages resulted in developmentally arrested parasites and prevented mosquito transmission, and these effects were independent of the previously proposed function for CDPK1 in regulating parasite motility. In-depth translational and transcriptional profiling of arrested parasites revealed that CDPK1 translationally activates mRNA species in the developing zygote that in macrogametes remain repressed via their 3' and 5'UTRs. These findings indicate that CDPK1 is a multifunctional protein that translationally regulates mRNAs to ensure timely and stage-specific protein expression.
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