title: The Arabidopsis paralogs, PUB46 and PUB48, encoding U-box E3 ubiquitin ligases, are essential for plant response to drought stress.
abstract: Plants respond to abiotic stress on physiological, biochemical and molecular levels. This includes a global change in their cellular proteome achieved by changes in the pattern of their protein synthesis and degradation. The ubiquitin-proteasome system (UPS) is a key player in protein degradation in eukaryotes. Proteins are marked for degradation by the proteasome by coupling short chains of ubiquitin polypeptides in a three-step pathway. The last and regulatory stage is catalyzed by a member of a large family of substrate-specific ubiquitin ligases.
  
  
  
  We have identified AtPUB46 and AtPUB48-two paralogous genes that encode ubiquitin ligases (E3s)-to have a role in the plant environmental response. The AtPUB46, -47, and -48 appear as tandem gene copies on chromosome 5, and we present a phylogenetic analysis that traces their evolution from an ancestral PUB-ARM gene. Single homozygous T-DNA insertion mutants of AtPUB46 and AtPUB48 displayed hypersensitivity to water stress; this was not observed for similar mutants of AtPUB47. Although the three genes show a similar spatial expression pattern, the steady state levels of their transcripts are differentially affected by abiotic stresses and plant hormones.
  
  
  
  AtPUB46 and AtPUB48 encode plant U-Box E3s and are involved in the response to water stress. Our data suggest that despite encoding highly homologous proteins, AtPUB46 and AtPUB48 biological activity does not fully overlap.
authors.affiliation: Department of Life Sciences, Ben-Gurion University of the Negev, 1 Ben-Gurion Blvd, Beer-Sheva, 8410501, Israel.|The Doris and Bertie I. Black Center for Bioenergetics in Life Sciences, Ben-Gurion University of the Negev, 1 Ben-Gurion Blvd, Beer-Sheva, 8410501, Israel.
authors.forename: Guy
authors.initials: G
authors.lastname: Adler
authors.affiliation: Department of Life Sciences, Ben-Gurion University of the Negev, 1 Ben-Gurion Blvd, Beer-Sheva, 8410501, Israel.|The Doris and Bertie I. Black Center for Bioenergetics in Life Sciences, Ben-Gurion University of the Negev, 1 Ben-Gurion Blvd, Beer-Sheva, 8410501, Israel.
authors.forename: Zvia
authors.initials: Z
authors.lastname: Konrad
authors.affiliation: Department of Life Sciences, Ben-Gurion University of the Negev, 1 Ben-Gurion Blvd, Beer-Sheva, 8410501, Israel.|The Doris and Bertie I. Black Center for Bioenergetics in Life Sciences, Ben-Gurion University of the Negev, 1 Ben-Gurion Blvd, Beer-Sheva, 8410501, Israel.
authors.forename: Lyad
authors.initials: L
authors.lastname: Zamir
authors.affiliation: Department of Life Sciences, Ben-Gurion University of the Negev, 1 Ben-Gurion Blvd, Beer-Sheva, 8410501, Israel.|The Doris and Bertie I. Black Center for Bioenergetics in Life Sciences, Ben-Gurion University of the Negev, 1 Ben-Gurion Blvd, Beer-Sheva, 8410501, Israel.
authors.forename: Amit Kumar
authors.initials: AK
authors.lastname: Mishra
authors.affiliation: Department of Life Sciences, Ben-Gurion University of the Negev, 1 Ben-Gurion Blvd, Beer-Sheva, 8410501, Israel.
authors.forename: Dina
authors.initials: D
authors.lastname: Raveh
authors.affiliation: Department of Life Sciences, Ben-Gurion University of the Negev, 1 Ben-Gurion Blvd, Beer-Sheva, 8410501, Israel. barzvi@bgu.ac.il.|The Doris and Bertie I. Black Center for Bioenergetics in Life Sciences, Ben-Gurion University of the Negev, 1 Ben-Gurion Blvd, Beer-Sheva, 8410501, Israel. barzvi@bgu.ac.il.
authors.forename: Dudy
authors.initials: D
authors.lastname: Bar-Zvi
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D032461:Chromosomes, Plant / Q000235:genetics; D055864:Droughts; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D009154:Mutation / Q000235:genetics; D013312:Stress, Physiological / Q000235:genetics*; D044767:Ubiquitin-Protein Ligases / Q000235:genetics* / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D044767:Ubiquitin-Protein Ligases