title: Unusual properties of Plasmodium falciparum actin: new insights into microfilament dynamics of apicomplexan parasites.
abstract: Plasmodium falciparum, the etiologic agent of malaria, is a facultative intracellular parasite of the phylum Apicomplexa. A limited turnover of microfilaments takes place beneath the parasite plasma membrane, but the cytoplasm of apicomplexans is virtually devoid of F-actin. We produced Plasmodium actin in yeast. Purified recombinant Plasmodium actin polymerized inefficiently unless both gelsolin and phalloidin were added. The resulting actin polymers appeared fragmented in the fluorescence microscope. Plasmodium actin bound DNaseI about 200 times weaker than bovine non-muscle actin. Our findings suggest that the unique properties of Plasmodium actin can explain some of the unusual features of apicomplexan parasite microfilaments.
authors.affiliation: Department of Biochemistry and Biophysics, Stockholm University, Roslagstullsbacken 15, 11421 Stockholm, Sweden. herwig@dbb.su.se
authors.forename: Herwig
authors.initials: H
authors.lastname: Schüler
authors.forename: Ann-Kristin
authors.initials: AK
authors.lastname: Mueller
authors.forename: Kai
authors.initials: K
authors.lastname: Matuschewski
mesh_terms: D000199:Actins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D018076:DNA, Complementary; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000378:metabolism*; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
chemical_list: D000199:Actins; D018076:DNA, Complementary