N-Linked Glycoproteins Are Related to Schizogony of the Intraerythrocytic Stage in Plasmodium falciparum

doi:10.1074/jbc.271.24.14452

N-Linked Glycoproteins Are Related to Schizogony of the Intraerythrocytic Stage in *Plasmodium falciparum**

From the ^‡ Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil,
the ^§ Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina, and the
^¶ Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil

^∥ To whom correspondence should be addressed:
Dept. de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av. Lineu Prestes 1374, CEP 05508-900, São Paulo SP, Brazil.
Tel.: 55-11-818-7330; Fax: 55-11-818-7417; E-mail: amkatzin{at}biomed.icb2.usp.br

Abstract

Although the existence of O-linked oligosaccharide residues in glycoproteins of Plasmodium falciparum has been shown, the existence of N-linked glycoproteins is still a matter of controversy and skepticism.

This report demonstrates the unequivocal presence of N-linked glycoproteins in P. falciparum, principally in the ring and young trophozoite stages of the intraerythrocytic cycle. These glycoproteins lose their capacity to bind to concanavalin A-Sepharose after treatment of cultures with tunicamycin under conditions that do not affect protein synthesis. When the glycoproteins were treated with N-Glycanase®, oligosaccharides were released. It was possible to identify an N-linked glycoprotein of >200 kDa in the ring stage and also N-linked glycoproteins in the range of 200–30 kDa in the trophozoite stage. Treatment of trophozoites with 12 μM tunicamycin inhibited differentiation to the schizont stage.

To our knowledge, this is the first report in the literature unequivocally showing N-linked glycoproteins in trophozoites of P. falciparum as well as their importance for the differentiation of the intraerythrocytic stages of this parasite.

Footnotes

↵* This work was supported by grants from Fundaçăo Amparo a Pesquisa do Estado de Săo Paulo and Conselho Nacional Desenvolvimento Científico e Tecnológico (Brazil). The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¹ The abbreviations used are:

HRP-1

histidine-rich protein 1

HRP-2

histidine-rich protein 2

MSP1

merozoite surface protein 1

TUNYC

tunicamycin

CHX

cycloheximide

Dol

dolichol

ConA

concanavalin A

PAGE

polyacrylamide gel electrophoresis

HPLC

high-performance liquid chromatography.
- Received March 18, 1996.