A Plasmodium falciparum protein kinase with two unusually large kinase inserts

Kappes, Barbara; Yang, Jiewu; Suetterlin, Bernd W.; Rathgeb-Szabo, Klara; Lindt, Meinrad; Franklin, Richard M.

doi:10.1016/0166-6851(95)00075-c

Cited by 22 publications

(9 citation statements)

References 47 publications

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“…Alternatively, the extremely charged repeat structures present in the C-terminus of the PfMAP gene product may alter the migration behaviour of the protein during SDS-PAGE. A 30 kDa reduction of the apparent molecular mass, probably caused by the amino acid content of the protein, was observed in the PfPK1 kinase (Kappes et al, 1995).…”

Section: Discussionmentioning

confidence: 94%

Characterization of a mitogen‐activated protein (MAP) kinase from Plasmodium falciparum

Graeser

Küry

Franklin

et al. 1997

Molecular Microbiology

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SummaryA mitogen-activated protein (MAP) kinase gene, PfMAP, from Plasmodium falciparum was recently identified. We expressed this gene in Escherichia coli to test whether it encodes a functional MAP kinase. Recombinant PfMAP kinase autophosphorylates on both the tyrosine and threonine residues within the TXY motif, and readily phosphorylates myelin basic protein as exogenous substrate. This identifies the PfMAP gene product as a true member of the growing family of MAP kinases. Wild-type PfMAP kinase expressed in COS-7 (SV40 transformed African green monkey kidney) cells seemed to induce apoptosis in these cells. Western blots and immunoprecipitations indicated that the kinase is expressed during the growth of the parasite in the red blood cell as three major forms: truncated forms with apparent molecular masses of 40 kDa and 80 kDa, and as a protein of Ϸ150 kDa. The 40 kDa form is present throughout the intraerythrocytic development, whereas the two larger forms are only detected in mature parasites. The 40 kDa and 80 kDa forms are tyrosine phosphorylated, indicating that they represent the active forms of the PfMAP kinase. The total PfMAP kinase activity constantly increases with the maturation of the parasite.

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Section: Discussionmentioning

confidence: 94%

Characterization of a mitogen‐activated protein (MAP) kinase from Plasmodium falciparum

Graeser

Küry

Franklin

et al. 1997

Molecular Microbiology

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“…Their position either in a cluster (composed of PfPK6 and Pfcrk-5) that is intermediate between the CDK and the MAPK groups, or in a cluster (composed of Pfcrk-4 and uncharacterized MAL13P1.196) at the base of the CDK/MAPK/GSK3 branch, is consistent with these early observations. Three GSK3-related kinases, two of which [PF08_0044 and PFC0525c] have been characterised previously [36,37], form a cluster within the CMGC group. Four additional enzymes form another cluster that includes human Clk1, one of which is a previously described LAMMER-related kinase [PF14_0431] [38].…”

Section: Resultsmentioning

confidence: 99%

Protein kinases of the human malaria parasite Plasmodium falciparum: the kinome of a divergent eukaryote

et al. 2004

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Background: Malaria, caused by the parasitic protist Plasmodium falciparum, represents a major public health problem in the developing world. The P. falciparum genome has been sequenced, which provides new opportunities for the identification of novel drug targets. Eukaryotic protein kinases (ePKs) form a large family of enzymes with crucial roles in most cellular processes; hence malarial ePKS represent potential drug targets. We report an exhaustive analysis of the P. falciparum genomic database (PlasmoDB) aimed at identifying and classifying all ePKs in this organism.

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“…First, the catalytic domain is larger in Pfmap-2 than in other members of the MAPK family, because of the presence of three insertions in poorly conserved regions (residues 263-282, 328 -337, and 348 -364). Similar but much longer atypical insertions, whose functional significance is unknown, have been found in another P. falciparum protein kinase (21). Unlike Pfmap-1 and Pfcrk-1 (a P. falciparum CDK-related kinase) (13), Pfmap-2 does not possess a large extension with repeated amino acid motifs at its amino or carboxyl terminus; the region upstream of the Pfmap-2 catalytic domain, however, is larger than that of most members of the MAPK family.…”

Section: Isolation Of a P Falciparum Gene Encoding A Protein Relatedmentioning

confidence: 92%

An Atypical Mitogen-activated Protein Kinase (MAPK) Homologue Expressed in Gametocytes of the Human Malaria Parasite Plasmodium falciparum

Dorin¹,

Alano²,

Boccaccio³

et al. 1999

Journal of Biological Chemistry

117

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The cDNA encoding Pfmap-2, an enzyme of the human malaria parasite Plasmodium falciparum, was cloned, sequenced, and expressed in Escherichia coli. The open reading frame carried by the Pfmap-2 cDNA encodes a 508-amino acid polypeptide of 59.2 kDa with maximal homology to mitogen-activated protein kinases (MAPKs) from various organisms. The purified recombinant enzyme displayed functional characteristics of MAPKs such as (i) ability to undergo autophosphorylation, (ii) ability to phosphorylate myelin basic protein, a classical MAPK substrate, (iii) regulation of kinase activity by a MAPK-specific phosphatase, and (iv) ability to be activated by component(s) present in cell extracts. Mutational analysis of the recombinant protein allowed the identification of residues that are important for enzymatic activity. Northern blot analysis and immunofluorescence assays indicated that Pfmap-2 is expressed specifically in gametocytes, the form that is responsible for transmission of the parasite to the mosquito vector. Gametocyte extracts activated recombinant Pfmap-2 more efficiently than extracts from asexual parasites, which is consistent with this stage specificity. Despite its overall high level of homology to MAPKs, Pfmap-2 presents the peculiarity of not possessing the conserved threonine-X-tyrosine activation motif usually found in enzymes of this family; instead, it has a threonine-serine-histidine at the same location. This atypical feature formed the basis for a detailed analysis of the primary structure of MAPKs, allowing us to define an operational MAPK signature, which is shared by Pfmap-2. The fact that no MAPK from vertebrates diverge in the activation motif suggests that the fine mechanisms of Pfmap-2 regulation may offer an opportunity for antimalarial drug targeting.The spread of drug resistance in Plasmodium falciparum, the parasite responsible for the lethal form of human malaria, represents one of the most pressing public health problems in many parts of the world (1, 2). Parasites that are resistant to anti-malarials are selected under drug pressure in treated patients, develop into male and female gametocytes that are infective to the mosquito vector, and hence can be transmitted to new human hosts. One possible way to limit the spread of P. falciparum resistance might consist in interfering with sexual development of the parasite, thereby preventing transmission. A rational approach to this goal requires a detailed knowledge of the molecular mechanisms of Plasmodium sexual development.After invasion of a red blood cell, a merozoite can either embark on a new cycle of asexual multiplication leading to the formation of a schizont ultimately releasing 8 -32 new merozoites or undergo sexual differentiation (gametocytogenesis), a process characterized by cell cycle arrest, a shift in the transcriptional repertoire, and morphological changes (reviewed in Refs. 3-4). Mature gametocytes maintain their cell cycle arrested while in the blood of the human host, but this block is relieved immediately after th...

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A Plasmodium falciparum protein kinase with two unusually large kinase inserts

Cited by 22 publications

References 47 publications

Characterization of a mitogen‐activated protein (MAP) kinase from Plasmodium falciparum

Characterization of a mitogen‐activated protein (MAP) kinase from Plasmodium falciparum

Protein kinases of the human malaria parasite Plasmodium falciparum: the kinome of a divergent eukaryote

An Atypical Mitogen-activated Protein Kinase (MAPK) Homologue Expressed in Gametocytes of the Human Malaria Parasite Plasmodium falciparum

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