title: The Arabidopsis heavy metal P-type ATPase HMA5 interacts with metallochaperones and functions in copper detoxification of roots.
abstract: Since copper (Cu) is essential in key physiological oxidation reactions, organisms have developed strategies for handling Cu while avoiding its potentially toxic effects. Among the tools that have evolved to cope with Cu is a network of Cu homeostasis factors such as Cu-transporting P-type ATPases that play a key role in transmembrane Cu transport. In this work we present the functional characterization of an Arabidopsis Cu-transporting P-type ATPase, denoted heavy metal ATPase 5 (HMA5), and its interaction with Arabidopsis metallochaperones. HMA5 is primarily expressed in roots, and is strongly and specifically induced by Cu in whole plants. We have identified and characterized plants carrying two independent T-DNA insertion alleles, hma5-1 and hma5-2. Both mutants are hypersensitive to Cu but not to other metals such as iron, zinc or cadmium. Interestingly, root tips from Cu-treated hma5 mutants exhibit a wave-like phenotype at early stages and later on main root growth completely arrests whereas lateral roots emerge near the crown. Accordingly, these lines accumulate Cu in roots to a greater extent than wild-type plants under Cu excess. Finally, yeast two-hybrid experiments demonstrate that the metal-binding domains of HMA5 interact with Arabidopsis ATX1-like Cu chaperones, and suggest a regulatory role for the plant-specific domain of the CCH Cu chaperone. Based on these findings, we propose a role for HMA5 in Cu compartmentalization and detoxification.
authors.affiliation: Departament de Bioquímica i Biologia Molecular, Universitat de València, Av. Dr Moliner, 50, E-46100 Burjassot, Valencia, Spain.
authors.forename: Nuria
authors.initials: N
authors.lastname: Andrés-Colás
authors.forename: Vicente
authors.initials: V
authors.lastname: Sancenón
authors.forename: Susana
authors.initials: S
authors.lastname: Rodríguez-Navarro
authors.forename: Sonia
authors.initials: S
authors.lastname: Mayo
authors.forename: Dennis J
authors.initials: DJ
authors.lastname: Thiele
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Ecker
authors.forename: Sergi
authors.initials: S
authors.lastname: Puig
authors.forename: Lola
authors.initials: L
authors.lastname: Peñarrubia
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D003300:Copper / Q000378:metabolism*; D017931:DNA Primers; D017343:Genes, Plant; D018832:Molecular Chaperones / Q000378:metabolism*; D008969:Molecular Sequence Data; D018517:Plant Roots / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D017386:Sequence Homology, Amino Acid
chemical_list: D029681:Arabidopsis Proteins; D017931:DNA Primers; D018832:Molecular Chaperones; D012333:RNA, Messenger; D003300:Copper; D000251:Adenosine Triphosphatases