Molecular and Biochemical Parasitology 87 (1997) 205–210

Short communication

Protein phosphorylation during sexual differentiation in themalaria parasite Plasmodium falciparum

Nirbhay Kumar *

Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, 615 N. Wolfe Street, Baltimore,MD 21205, USA

Received 28 February 1997; received in revised form 1 April 1997; accepted 3 April 1997

Keywords: Plasmodium falciparum ; Malaria; Sexual stages; Phosphorylation; Pfg27

The unicellular protozoan parasites belongingto the genus Plasmodium have a complex life cyclein which the asexual multiplication of parasites inthe vertebrate host alternates with an obligatesexual reproduction in the mosquito vector. Ery-throcytic sexual stages (male and female gameto-cytes) are produced by sexual differentiation ofasexual stages within the vertebrate host and areresponsible for transmitting the parasite to themosquito vector. The sexual reproduction of theparasites in the mosquitoes involves a complex setof events leading to the formation of extracellularfemale and motile male gametes, which undergofertilization and further development [1]. It isduring the mating between male and female

gametes that genetic recombination occurs duringmeiotic division of fertilized zygotes. Mating isalso believed to be a major factor contributing toenormous genetic diversity of the parasite popula-tion [2]. Such diverse parasites are then dissemi-nated into the human population during furthertransmission. Sexual differentiation and develop-ment of the malaria parasite thus occupies acentral place in the biology of this parasite whichposes a major health risk worldwide.

The initiation of sexual differentiation occursearly during invasion of erythrocytes by mero-zoites. A clonal population of haploid parasitescan generate both male and female gametocytes.Sexually differentiated parasites undergo pro-found morphological, biochemical and functionalchanges. These are accompanied by preferentialexpression of a number of proteins in a coordi-nated fashion during distinct maturation stages ofgametocytes defined as stages I–V [3–5]. Pfg27(Mr 27 000) is one such cytoplasmic protein abun-

Abbre6iations: SDS-PAGE, sodium dodecyl sulfate-poly-acrylamide gel electrophoresis; TLC, thin layer chromatogra-phy.

* Tel.: +1 410 9557177; fax: +1 410 9550105; e-mail:nkumar@phnet.sph.jhu.edu

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