Fatty acid acylation regulates trafficking of the unusual Plasmodium falciparum calpain to the nucleolus.
The Plasmodium falciparum genome encodes a single calpain. By generating P. falciparum clones expressing C-terminally tagged calpain, we localized this protein to the nucleolus. Pf_calpain possesses an unusual and long N-terminal domain in which we identified three subregions that are highly conserved among Plasmodium species. Two have putative targeting signals: a myristoylation motif and a nuclear localization sequence. We assessed their functionality. Our data show that the nuclear localization sequence is an active nuclear import motif that contains an embedded signal conferring nucleolar localization on various chimeras. The N-terminus is myristoylated at Gly2 and palmitoylated at Cys3 and Cys22. Palmitoylation status has an important role in dictating P. falciparum calpain localization. The targeting signals function in mammalian cells as well as in the parasite. P. falciparum calpain is a unique nucleolar protein with an interesting mechanism of targeting.
Russo
Ilaria
I
Howard Hughes Medical Institute, Washington University School of Medicine, Department of Molecular Microbiology, St Louis, Missouri 63110, USA.
Oksman
Anna
A
Goldberg
Daniel E
DE
D000215:Acylation; D000818:Animals; D002154:Calpain / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002466:Cell Nucleolus / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism*; D006801:Humans; D054878:Lipoylation; D019913:Nuclear Localization Signals; D010802:Phylogeny; D010963:Plasmodium falciparum / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
D005227:Fatty Acids; D019913:Nuclear Localization Signals; D015800:Protozoan Proteins; D002154:Calpain