A putative protein serine/threonine phosphatase from Plasmodium falciparum contains a large N-terminal extension and five unique inserts in the catalytic domain.

Plasmodium falciparum possesses a complex life cycle involving two different hosts and interactions with multiple cell types. During the various stages of the life cycle the parasite undergoes cell growth and division, development and differentiation. Sexual stage development, gametocytogenesis in the host and gametogenesis in the mosquito, is accompanied by biochemical and morphological changes in the parasite. The molecular and cellular mechanisms involved in regulation of proliferation, development and differentiation of P. falciparum are unclear. However, inhibitors of protein kinases and phosphatases can interfere with parasite growth [1], suggesting a requirement for phosphorylation–dephosphorylation in control of the parasite life cycle. Reversible phosphorylation has been shown to play an important role in invasion of erythrocytes by merozoites [2] and in intraerythrocytic growth and development [3]. Recently, a number of protein serine/threonine kinase genes have been isolated from P. falciparum [4–7]. Abbre6iations: PPP, PP-1/PP-2A/PP-2B protein serine/ threonine phosphatase family; PfPP-a, Plasmodium falciparum protein serine/threonine phosphatase a ; PfPP-b, Plasmodium falciparum protein serine/threonine phosphatase b ; PFGE, pulse-field gel electrophoresis. * Corresponding author. Present address: Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK. Tel.: +44 1865 275722; fax: +44 1865 275721; e-mail: [email protected] 1 Note: Nucleotide sequence data reported in this paper are available in the GenBankTM, EMBL and DDJB databases under the accession number U88869.