Title

Characterization Of A Novel Serine/Threonine Protein Phosphatase (Pfppj) From The Malaria Parasite, Plasmodium Falciparum

Keywords

Okadaic acid; Plasmodium falciparum; Protein phosphatase; Stage-specific expression

Abstract

A novel protein phosphatase cDNA of the PPP superfamily was identified from the malaria parasite, Plasmodium falciparum (Pf), and tentatively named PfPPJ. The predicted primary structure of the phosphatase contained all the known conserved motifs of the PPP superfamily essential for catalytic activity. The enzyme was specific for dephosphorylation of phosphoserine and phosphothreonine residues with very little activity against phosphotyrosine residues. However, the sequence at its C-terminal end was unique, and was consistent with its resistance to the classical PP2A-specific inhibitors such as okadaic acid and microcystin-LR, and the PP1-specific inhibitor, mammalian heat-stable inhibitor-2 (I-2). Even the catalytic core of PfPPJ had a sequence substantially different from the other PPPs such that PfPPJ could be placed in an apparently separate phylogenetic branch. At 294 amino acids residues, PfPPJ was one of the smallest okadaic acid-resistant PPP phosphatases known. By Northern blot analysis, the expression of the PfPPJ mRNA showed the following pattern: schizont > ring > trophozoite, which closely paralleled the expression of the protein, as determined by immunofluorescence. Together, these results suggested a parasitic stage-specific transcriptional regulation of this novel and potentially unique protozoan phosphatase. © 2001 Elsevier Science B.V.

Publication Date

6-11-2001

Publication Title

Molecular and Biochemical Parasitology

Volume

115

Issue

1

Number of Pages

29-39

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1016/S0166-6851(01)00260-2

Socpus ID

0035019534 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/0035019534

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