<i>Plasmodium </i>Condensin Core Subunits SMC2/SMC4 Mediate Atypical Mitosis and Are Essential for Parasite Proliferation and Transmission

Condensin is a multi-subunit protein complex regulating chromosome condensation and segregation during cell division. In Plasmodium spp., the causative agent of malaria, cell division is atypical and the role of condensin is unclear. Here we examine the role of SMC2 and SMC4, the core subunits of condensin, during endomitosis in schizogony and endoreduplication in male gametogenesis. During early schizogony, SMC2/SMC4 localize to a distinct focus, identified as the centromeres by NDC80 fluorescence and chromatin immunoprecipitation sequencing (ChIP-seq) analyses, but do not form condensin I or II complexes. In mature schizonts and during male gametogenesis, there is a diffuse SMC2/SMC4 distribution on chromosomes and in the nucleus, and both condensin I and condensin II complexes form at these stages. Knockdown of smc2 and smc4 gene expression reveals essential roles in parasite proliferation and transmission. The condensin core subunits (SMC2/SMC4) form different complexes and may have distinct functions at various stages of the parasite life cycle

Essential role of GEXP15, a specific Protein Phosphatase type 1 partner, in Plasmodium berghei in asexual erythrocytic proliferation and transmission.

The essential and distinct functions of Protein Phosphatase type 1 (PP1) catalytic subunit in eukaryotes are exclusively achieved through its interaction with a myriad of regulatory partners. In this work, we report the molecular and functional characterization of Gametocyte EXported Protein 15 (GEXP15), a Plasmodium specific protein, as a regulator of PP1. In vitro interaction studies demonstrated that GEXP15 physically interacts with PP1 through the RVxF binding motif in P. berghei. Functional assays showed that GEXP15 was able to increase PP1 activity and the mutation of the RVxF motif completely abolished this regulation. Immunoprecipitation assays of tagged GEXP15 or PP1 in P. berghei followed by immunoblot or mass spectrometry analyses confirmed their interaction and showed that they are present both in schizont and gametocyte stages in shared protein complexes involved in the spliceosome and proteasome pathways and known to play essential role in parasite development. Phenotypic analysis of viable GEXP15 deficient P. berghei blood parasites showed that they were unable to develop lethal infection in BALB/c mice or to establish experimental cerebral malaria in C57BL/6 mice. Further, although deficient parasites produced gametocytes they did not produce any oocysts/sporozoites indicating a high fitness cost in the mosquito. Global proteomic and phosphoproteomic analyses of GEXP15 deficient schizonts revealed a profound defect with a significant decrease in the abundance and an impact on phosphorylation status of proteins involved in regulation of gene expression or invasion. Moreover, depletion of GEXP15 seemed to impact mainly the abundance of some specific proteins of female gametocytes. Our study provides the first insight into the contribution of a PP1 regulator to Plasmodium virulence and suggests that GEXP15 affects both the asexual and sexual life cycle

Women convicted for violent offenses: Adverse childhood experiences, low level of education and poor mental health

<p>Abstract</p> <p>Background</p> <p>In past years, the female offender population has grown, leading to an increased interest in the characteristics of female offenders. The aim of this study was to assess the prevalence of female violent offending in a Swiss offender population and to compare possible socio-demographic and offense-related gender differences.</p> <p>Methods</p> <p>Descriptive and bivariate logistic regression analyses were performed for a representative sample of N = 203 violent offenders convicted in Zurich, Switzerland.</p> <p>Results</p> <p>7.9% (N = 16) of the sample were female. Significant gender differences were found: Female offenders were more likely to be married, less educated, to have suffered from adverse childhood experiences and to be in poor mental health. Female violent offending was less heterogeneous than male violent offending, in fact there were only three types of violent offenses females were convicted for in our sample: One third were convicted of murder, one third for arson and only one woman was convicted of a sex offense.</p> <p>Conclusions</p> <p>The results of our study point toward a gender-specific theory of female offending, as well as toward the importance of developing models for explaining female criminal behavior, which need to be implemented in treatment plans and intervention strategies regarding female offenders.</p

Analysis of the Ser/Thr protein phosphatase type 1 (PP1) interactome in plasmodium falciparum : molecular and functional characterization of the Gametocyte EXported Protein 15

L’un des obstacles majeurs au développement de nouveaux antipaludiques est notre connaissance limitée de la biologie parasitaire et la rareté des cibles thérapeutiques potentielles identifiées. Les interactions protéines-protéines sont impliquées et essentielles dans divers processus biologiques incluant les modifications post-traductionnelles. Les interactions substrats-kinases ou phosphatases sont considérées comme une liaison transitoire et jouent un rôle central et essentiel dans le cycle cellulaire de Plasmodium. La Ser/Thr Protéine Phosphatase de Type 1 (PP1), l’une des phosphatases majeurs des eucaryotes, est essentielle à la survie du parasite Plasmodium falciparum, responsable du paludisme. Elle est régulée par diverses sous-unités régulatrices dont plus de 200 ont été identifiées chez l’Homme, mais seulement 4 chez Plasmodium.Afin d’explorer le réseau de régulation de la P. falciparum PP1 (PfPP1), nous avons utilisé trois approches complémentaires pour caractériser l’interactome de la PfPP1. La purification par co-affinité suivie d'une analyse par spectrométrie de masse a identifié 6 protéines interagissant avec la PfPP1 dont 3 contenaient le motif consensus d’interaction RVxF, 2 autres le motif Fxx[RK]x[RK], également connu pour interagir avec la phosphatase et une protéine avec les deux motifs de liaison. Le criblage par double hybride chez la levure a identifié 134 protéines dont 30 présentent le motif RVxF et 20 ont le motif de liaison Fxx[RK]x[RK]. Le criblage in silico du génome de P. falciparum en utilisant une séquence consensus du motif RVxF a révélé 55 partenaires potentiels de la PfPP1. Afin de confirmer l’interaction de certaines protéines, 35 partenaires candidats ont été validés par un test d’interaction de type ELISA. Les résultats ont permis de détecter aussi bien des partenaires conservés de la PP1 qu'un nombre élevé d'interacteurs spécifiques à la PP1 du parasite et montrent une grande diversité dans les fonctions biologiques impliquant la PP1 chez Plasmodium. Parmi ces candidats, un partenaire appelé Gametocyte EXported Protein 15 (GEXP15) a été confirmé comme un réel partenaire de la PfPP1 par différentes approches. De plus, GEXP15 est surexprimé chez les gamétocytes, stade responsable de la transmission du parasite chez le moustique. Ces résultats ainsi que des études fonctionnelles seront présentés.A major obstacle in the development of novel anti-malarials is our limited knowledge of basic parasite biology and the paucity of identified potential intervention targets. Protein-protein interactions are involved and essential in broad range of biological processes including the post-translational modifications. Substrate-kinase or phosphatase interactions are considered as transient binding and play a central and essential role in Plasmodium cell cycle. The Ser/Thr Protein Phosphatase Type 1 (PP1), one of the main contributors of eukaryotic phosphatase activity, is essential to malaria parasite Plasmodium falciparum and is highly regulated by many regulatory subunits. In humans, there are about 200 distinct regulators, however, only 4 have been so far reported in Plasmodium.To explore the P. falciparum PP1 (PfPP1) regulatory network as complete as possible, we carried out three complementary approaches to characterize the PfPP1 interactome. Co-affinity purification followed by Mass Spectrometry-based proteomics identified 6 PfPP1 interacting proteins (PIPs) of which 3 contained the RVxF consensus binding motif, 2 PIPs with a Fxx[RK]x[RK] binding motif, one with both binding motifs. The Yeast Two-Hybrid screening identified 134 proteins of which 30 have the RVxF binding motif and 20 contain the Fxx[RK]x[RK] binding motif. The in silico screen of the P. falciparum genome using a consensus RVxF motif as template revealed the presence of 55 potential PfPP1 interacting proteins. As further demonstration, 35 candidate partners were validated in an independent ELISA-based assay using recombinant proteins. The data reports several conserved PP1 interacting proteins as well as a high number of specific interactors to PfPP1, indicating a high diversity of biological functions for PP1 in Plasmodium. Among these candidates, one partner assigned as Gametocyte EXported Protein 15 (GEXP15) has been confirmed as a direct interactor of PfPP1 by different approaches. In addition, GEXP15 is over-expressed during gametocyte stage, responsible for the transmission of the parasite in the mosquito. These results as well as functional studies will be presented and discussed

Analyse de l’interactome de la Ser/Thr protéine phosphatase de type 1 (PP1) chez plasmodium falciparum : caractérisation moléculaire et fonctionnelle de Gametocyte EXported Protein 15

A major obstacle in the development of novel anti-malarials is our limited knowledge of basic parasite biology and the paucity of identified potential intervention targets. Protein-protein interactions are involved and essential in broad range of biological processes including the post-translational modifications. Substrate-kinase or phosphatase interactions are considered as transient binding and play a central and essential role in Plasmodium cell cycle. The Ser/Thr Protein Phosphatase Type 1 (PP1), one of the main contributors of eukaryotic phosphatase activity, is essential to malaria parasite Plasmodium falciparum and is highly regulated by many regulatory subunits. In humans, there are about 200 distinct regulators, however, only 4 have been so far reported in Plasmodium.To explore the P. falciparum PP1 (PfPP1) regulatory network as complete as possible, we carried out three complementary approaches to characterize the PfPP1 interactome. Co-affinity purification followed by Mass Spectrometry-based proteomics identified 6 PfPP1 interacting proteins (PIPs) of which 3 contained the RVxF consensus binding motif, 2 PIPs with a Fxx[RK]x[RK] binding motif, one with both binding motifs. The Yeast Two-Hybrid screening identified 134 proteins of which 30 have the RVxF binding motif and 20 contain the Fxx[RK]x[RK] binding motif. The in silico screen of the P. falciparum genome using a consensus RVxF motif as template revealed the presence of 55 potential PfPP1 interacting proteins. As further demonstration, 35 candidate partners were validated in an independent ELISA-based assay using recombinant proteins. The data reports several conserved PP1 interacting proteins as well as a high number of specific interactors to PfPP1, indicating a high diversity of biological functions for PP1 in Plasmodium. Among these candidates, one partner assigned as Gametocyte EXported Protein 15 (GEXP15) has been confirmed as a direct interactor of PfPP1 by different approaches. In addition, GEXP15 is over-expressed during gametocyte stage, responsible for the transmission of the parasite in the mosquito. These results as well as functional studies will be presented and discussed.L’un des obstacles majeurs au développement de nouveaux antipaludiques est notre connaissance limitée de la biologie parasitaire et la rareté des cibles thérapeutiques potentielles identifiées. Les interactions protéines-protéines sont impliquées et essentielles dans divers processus biologiques incluant les modifications post-traductionnelles. Les interactions substrats-kinases ou phosphatases sont considérées comme une liaison transitoire et jouent un rôle central et essentiel dans le cycle cellulaire de Plasmodium. La Ser/Thr Protéine Phosphatase de Type 1 (PP1), l’une des phosphatases majeurs des eucaryotes, est essentielle à la survie du parasite Plasmodium falciparum, responsable du paludisme. Elle est régulée par diverses sous-unités régulatrices dont plus de 200 ont été identifiées chez l’Homme, mais seulement 4 chez Plasmodium.Afin d’explorer le réseau de régulation de la P. falciparum PP1 (PfPP1), nous avons utilisé trois approches complémentaires pour caractériser l’interactome de la PfPP1. La purification par co-affinité suivie d'une analyse par spectrométrie de masse a identifié 6 protéines interagissant avec la PfPP1 dont 3 contenaient le motif consensus d’interaction RVxF, 2 autres le motif Fxx[RK]x[RK], également connu pour interagir avec la phosphatase et une protéine avec les deux motifs de liaison. Le criblage par double hybride chez la levure a identifié 134 protéines dont 30 présentent le motif RVxF et 20 ont le motif de liaison Fxx[RK]x[RK]. Le criblage in silico du génome de P. falciparum en utilisant une séquence consensus du motif RVxF a révélé 55 partenaires potentiels de la PfPP1. Afin de confirmer l’interaction de certaines protéines, 35 partenaires candidats ont été validés par un test d’interaction de type ELISA. Les résultats ont permis de détecter aussi bien des partenaires conservés de la PP1 qu'un nombre élevé d'interacteurs spécifiques à la PP1 du parasite et montrent une grande diversité dans les fonctions biologiques impliquant la PP1 chez Plasmodium. Parmi ces candidats, un partenaire appelé Gametocyte EXported Protein 15 (GEXP15) a été confirmé comme un réel partenaire de la PfPP1 par différentes approches. De plus, GEXP15 est surexprimé chez les gamétocytes, stade responsable de la transmission du parasite chez le moustique. Ces résultats ainsi que des études fonctionnelles seront présentés

From Genes to Transcripts, a Tightly Regulated Journey in Plasmodium.

Over the past decade, we have witnessed significant progresses in understanding gene regulation in Apicomplexa including the human malaria parasite, Plasmodium falciparum. This parasite possesses the ability to convert in multiple stages in various hosts, cell types, and environments. Recent findings indicate that P. falciparum is talented at using efficient and complementary molecular mechanisms to ensure a tight control of gene expression at each stage of its life cycle. Here, we review the current understanding on the contribution of the epigenome, atypical transcription factors, and chromatin organization to regulate stage conversion in P. falciparum. The adjustment of these regulatory mechanisms occurring during the progression of the life cycle will be extensively discussed

Dynamic Chromatin Structure and Epigenetics Control the Fate of Malaria Parasites.

Multiple hosts and various life cycle stages prompt the human malaria parasite, Plasmodium falciparum, to acquire sophisticated molecular mechanisms to ensure its survival, spread, and transmission to its next host. To face these environmental challenges, increasing evidence suggests that the parasite has developed complex and complementary layers of regulatory mechanisms controlling gene expression. Here, we discuss the recent developments in the discovery of molecular components that contribute to cell replication and differentiation and highlight the major contributions of epigenetics, transcription factors, and nuclear architecture in controlling gene regulation and life cycle progression in Plasmodium spp