title: Identification and characterization of a FYVE domain from the early diverging eukaryote Giardia lamblia.
abstract: The morphology of the endomembrane system of Giardia lamblia appears to be significantly different from higher eukaryotes. Therefore, the molecular mechanisms controlling vesicular trafficking are also likely to be altered. Since FYVE domain is a known regulator of endosomal trafficking, the authors used BLAST search to identify FYVE domain(s) in G. lamblia. A 990 amino acid long putative FYVE domain-containing ORF was identified, which contains all the conserved sequence elements in the ligand binding pocket. Phylogenetic analysis reveals that this domain is significantly diverged. The authors have shown that the corresponding gene is expressed in G. lamblia trophozoites and cysts. In spite of this phylogenetic divergence, in vitro biochemical assay indicates that this domain preferentially binds to phosphatidylinositol 3-phosphate {PtdIns(3)P}and in vivo expression of the GFP-tagged G. lamblia FYVE domain in S. cerevisiae, displays its selective localization to PtdIns(3)P-enriched endosomes. This is the first study to characterize a PtdIns(3)P effector protein in this early-diverged eukaryote.
authors.affiliation: Biological Sciences, Indian Institute of Science Education and Research, Kolkata, India.
authors.forename: Abhishek
authors.initials: A
authors.lastname: Sinha
authors.forename: Sananda
authors.initials: S
authors.lastname: Mandal
authors.forename: Sumana
authors.initials: S
authors.lastname: Banerjee
authors.forename: Arjun
authors.initials: A
authors.lastname: Ghosh
authors.forename: Sandipan
authors.initials: S
authors.lastname: Ganguly
authors.forename: Alok Kumar
authors.initials: AK
authors.lastname: Sil
authors.forename: Srimonti
authors.initials: S
authors.lastname: Sarkar
mesh_terms: D000595:Amino Acid Sequence; D011992:Endosomes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D056890:Eukaryota / Q000737:chemistry / Q000145:classification / Q000235:genetics; D019143:Evolution, Molecular; D018507:Gene Expression Regulation, Developmental; D016829:Giardia lamblia / Q000737:chemistry / Q000145:classification / Q000235:genetics* / Q000254:growth & development; D008969:Molecular Sequence Data; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D011506:Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D011506:Proteins