title: Kinetoplastid PPEF phosphatases: dual acylated proteins expressed in the endomembrane system of Leishmania.
abstract: Bioinformatic analyses have been used to identify potential downstream targets of the essential enzyme N-myristoyl transferase in the TriTryp species, Leishmania major, Trypanosoma brucei and Trypanosoma cruzi. These database searches predict approximately 60 putative N-myristoylated proteins with high confidence, including both previously characterised and novel molecules. One of the latter is an N-myristoylated protein phosphatase which has high sequence similarity to the Protein Phosphatase with EF-Hand (PPEF) proteins identified in sensory cells of higher eukaryotes. In L. major and T. brucei, the PPEF-like phosphatases are encoded by single-copy genes and are constitutively expressed in all parasite life cycle stages. The N-terminus of LmPPEF is a substrate for N-myristoyl transferase and is also palmitoylated in vivo. The wild type protein has been localised to the endocytic system by immunofluorescence. The catalytic and fused C-terminal domains of the kinetoplastid and other eukaryotic PPEFs share high sequence similarity, but unlike their higher eukaryotic relatives, the C-terminal parasite EF-hand domains are degenerate and do not bind calcium.
authors.affiliation: Wellcome Trust Laboratories for Molecular Parasitology, Centre for Molecular Microbiology and Infection, Imperial College London, London SW7 2AZ, UK.
authors.forename: Elena
authors.initials: E
authors.lastname: Mills
authors.forename: Helen P
authors.initials: HP
authors.lastname: Price
authors.forename: Andrea
authors.initials: A
authors.lastname: Johner
authors.forename: Jenny E
authors.initials: JE
authors.lastname: Emerson
authors.forename: Deborah F
authors.initials: DF
authors.lastname: Smith
mesh_terms: D000217:Acyltransferases / Q000378:metabolism; D000818:Animals; D015152:Blotting, Northern; D015139:Blotting, Southern; D004721:Endoplasmic Reticulum / Q000737:chemistry; D018628:Gene Dosage; D005786:Gene Expression Regulation; D007150:Immunohistochemistry; D018320:Leishmania major / Q000201:enzymology* / Q000235:genetics; D018613:Microscopy, Confocal; D010749:Phosphoprotein Phosphatases / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D016053:RNA, Protozoan / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D014346:Trypanosoma brucei brucei / Q000201:enzymology* / Q000235:genetics; D014349:Trypanosoma cruzi / Q000201:enzymology* / Q000235:genetics
chemical_list: D012333:RNA, Messenger; D016053:RNA, Protozoan; D000217:Acyltransferases; C050480:glycylpeptide N-tetradecanoyltransferase; D010749:Phosphoprotein Phosphatases