title: Arabidopsis thaliana expresses two functional isoforms of Arvp, a protein involved in the regulation of cellular lipid homeostasis.
abstract: Arv1p is involved in the regulation of cellular lipid homeostasis in the yeast Saccharomyces cerevisiae. Here, we report the characterization of the two Arabidopsis thaliana ARV genes and the encoded proteins, AtArv1p and AtArv2p. The functional identity of AtArv1p and AtArv2p was demonstrated by complementation of the thermosensitive phenotype of the arv1Delta yeast mutant strain YJN1756. Both A. thaliana proteins contain the bipartite Arv1 homology domain (AHD), which consists of an NH(2)-terminal cysteine-rich subdomain with a putative zinc-binding motif followed by a C-terminal subdomain of 33 amino acids. Removal of the cysteine-rich subdomain has no effect on Arvp activity, whereas the presence of the C-terminal subdomain of the AHD is critical for Arvp function. Localization experiments of AtArv1p and AtArv2p tagged with green fluorescent protein (GFP) and expressed in onion epidermal cells demonstrated that both proteins are exclusively targeted to the endoplasmic reticulum. Analysis of beta-glucuronidase (GUS) activity in transgenic A. thaliana plants carrying chimeric ARV1::GUS and ARV2::GUS genes showed that ARV gene promoters direct largely overlapping patterns of expression that are restricted to tissues in which cells are actively dividing or expanding. The results of this study support the notion that plants, yeast and mammals share common molecular mechanisms regulating intracellular lipid homeostasis.
authors.affiliation: Departament de Bioquímica i Biologia Molecular, Facultat de Farmàcia, Universitat de Barcelona, Avda. Diagonal 643, Barcelona-08028, Spain.
authors.forename: Oriol
authors.initials: O
authors.lastname: Forés
authors.forename: Montserrat
authors.initials: M
authors.lastname: Arró
authors.forename: Albert
authors.initials: A
authors.lastname: Pahissa
authors.forename: Sergi
authors.initials: S
authors.lastname: Ferrero
authors.forename: Melody
authors.initials: M
authors.lastname: Germann
authors.forename: Joseph
authors.initials: J
authors.lastname: Stukey
authors.forename: Virginia
authors.initials: V
authors.lastname: McDonough
authors.forename: Joseph T
authors.initials: JT
authors.lastname: Nickels
authors.forename: Narciso
authors.initials: N
authors.lastname: Campos
authors.forename: Albert
authors.initials: A
authors.lastname: Ferrer
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000302:isolation & purification; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D006706:Homeostasis; D008055:Lipids / Q000502:physiology; D008565:Membrane Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics; D016415:Sequence Alignment
chemical_list: C467736:ARV1 protein, S cerevisiae; D029681:Arabidopsis Proteins; C513917:Arv1 protein, Arabidopsis; C513918:Arv2 protein, Arabidopsis; D018076:DNA, Complementary; D008055:Lipids; D008565:Membrane Proteins; D020033:Protein Isoforms; D029701:Saccharomyces cerevisiae Proteins