Higher plants possess two different types of ATX1-like copper chaperones

Puig, Sergi; Mira, Helena; Dorcey, Eavan; Sancenón, Vicente; Andrés-Colás, Nuria; Garcia‐Molina, Antoni; Burkhead, Jason L.; Gogolin, Kathryn A.; Abdel‐Ghany, Salah E.; Thiele, Dennis J.; Ecker, Joseph R.; Pilon, Marinus; Peñarrubia, Lola

doi:10.1016/j.bbrc.2006.12.215

Cited by 85 publications

(97 citation statements)

References 20 publications

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“…Arabidopsis AtCCS is necessary for activation of all three types of Cu/ZnSOD activity (Chu et al, 2005). AtATX1 interacts in vivo with two Cu-transporting Ptype ATPases HMA5 (Andres-Colas et al, 2006) and RAN1 (Puig et al, 2007) by yeast twohybrid. The intracellular metal trafficking pathway model composed of Cu transporter, Cu pump and Cu chaperone has been proposed (O'Halloran & Culotta, 2000), and based on such cooperative work, chaperones make a great contribution to the metal transport, detoxification and remobilization (Himelblau & Amasino, 2000;Robinson & Winge, 2010).…”

Section: Organic Acids Amino Acids and Chaperonesmentioning

confidence: 99%

Towards Understanding Plant Response to Heavy Metal Stress

Zhao¹,

Chu²

2011

Abiotic Stress in Plants - Mechanisms and Adaptations

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IntroductionMetals like zinc, iron and copper are essential micronutrients required for a wide range of physiological processes in all plant organs for the activities of various metal-dependent enzymes and proteins. However, they can also be toxic at elevated levels. Metals like arsenic, mercury, cadmium and lead are nonessential and potentially highly toxic. Once the cytosolic metal concentration in plant turns out of control, phytotoxicity of heavy metal inhibits transpiration and photosynthesis, disturbs carbohydrate metabolism, and drives the secondary stresses like nutrition stress and oxidative stress, which collectively affect the plant development and growth (Krämer & Clemens, 2005). Plants have developed a complex network of highly effective homeostatic mechanisms that serve to control the uptake, accumulation, trafficking, and detoxification of metals. Components of this network have been identified continuously, including metal transporters in charge of metal uptake and vacuolar transport; chelators involved in metal detoxification via buffering the cytosolic metal concentrations; and chaperones helping delivery and trafficking of metal ions (Clemens, 2001). This chapter summarizes heavy metal stress and detoxification in plant. Special focus is given to metallothionein, yet vacuolar metal transporters, phytochelatins as well as certain organic acids, amino acids, and chaperones are also addressed with recent advances. Besides, heavy metal-induced oxidative stress and tolerance as an example of abiotic stress cross-talk will be discussed.

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Section: Organic Acids Amino Acids and Chaperonesmentioning

confidence: 99%

Towards Understanding Plant Response to Heavy Metal Stress

Zhao¹,

Chu²

2011

Abiotic Stress in Plants - Mechanisms and Adaptations

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“…The homolog in yeast (Saccharomyces cerevisiae) ATX1 has been well characterized (Lin and Culotta, 1995;Lin et al, 1997;Pufahl et al, 1997) and found to be involved both in Cu homeostasis by specifically delivering Cu to heavy metal P-type ATPases and in defense against oxidative stress. When overexpressed in a yeast strain lacking the superoxide dismutase gene SOD1, both At-ATX1 and At-CCH can protect the mutant from active oxygen toxicity in a Cu-dependent manner (Himelblau et al, 1998;Puig et al, 2007). In our experiments, expression of NaKR1 or the C-terminal region alone (containing the HMA domain) failed to complement the reactive oxygen toxicity phenotype of yeast sod1D mutant (see Supplemental Figure 2 online), indicating that the HMA domain of NaKR1 functions differently than At-ATX1/ At-CCH when expressed in yeast.…”

Section: Nakr1 Encodes a Heavy Metal Coordinating Proteinmentioning

confidence: 99%

Arabidopsis NPCC6/NaKR1 Is a Phloem Mobile Metal Binding Protein Necessary for Phloem Function and Root Meristem Maintenance

et al. 2010

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SODIUM POTASSIUM ROOT DEFECTIVE1 (NaKR1; previously called NPCC6) encodes a soluble metal binding protein that is specifically expressed in companion cells of the phloem. The nakr1-1 mutant phenotype includes high Na + , K + , Rb + , and starch accumulation in leaves, short roots, late flowering, and decreased long-distance transport of sucrose. Using traditional and DNA microarray-based deletion mapping, a 7-bp deletion was found in an exon of NaKR1 that introduced a premature stop codon. The mutant phenotypes were complemented by transformation with the native gene or NaKR1-GFP (green fluorescent protein) and NaKR1-b-glucuronidase fusions driven by the native promoter. NAKR1-GFP was mobile in the phloem; it moved from companion cells into sieve elements and into a previously undiscovered symplasmic domain in the root meristem. Grafting experiments revealed that the high Na + accumulation was due mainly to loss of NaKR1 function in the leaves. This supports a role for the phloem in recirculating Na + to the roots to limit Na + accumulation in leaves. The onset of root phenotypes coincided with NaKR1 expression after germination. The nakr1-1 short root phenotype was due primarily to a decreased cell division rate in the root meristem, indicating a role in root meristem maintenance for NaKR1 expression in the phloem.

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“…Both CCH and ATX1 can complement the yeast atx1 mutant (Puig et al, 2007b). The analysis of amino acid alignment revealed the conserved Cu-binding motif in these two Cu chaperones.…”

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confidence: 98%

“…These Cu chaperones show open-faced b-sandwich global folding with a conserved MXCXXC Cu-binding motif (Harrison et al, 1999). Arabidopsis has at least three Cu chaperones, including the Cu chaperone for superoxide dismutase (SOD; CCS) and two homologs of yeast Antioxidant Protein1 (ATX1), the Copper Chaperone (CCH) and ATX1 (Casareno et al, 1998;Chu et al, 2005;Puig et al, 2007b). In yeast, CCS is required to transfer Cu to Cu/zinc (Zn)-SOD for the activity (Rae et al, 1999).…”

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Copper Chaperone Antioxidant Protein1 Is Essential for Copper Homeostasis

2012

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Copper (Cu) is essential for plant growth but toxic in excess. Specific molecular mechanisms maintain Cu homeostasis to facilitate its use and avoid the toxicity. Cu chaperones, proteins containing a Cu-binding domain(s), are thought to assist Cu intracellular homeostasis by their Cu-chelating ability. In Arabidopsis (Arabidopsis thaliana), two Cu chaperones, Antioxidant Protein1 (ATX1) and ATX1-Like Copper Chaperone (CCH), share high sequence homology. Previously, their Cu-binding capabilities were demonstrated and interacting molecules were identified. To understand the physiological functions of these two chaperones, we characterized the phenotype of atx1 and cch mutants and the cchatx1 double mutant in Arabidopsis. The shoot and root growth of atx1 and cchatx1 but not cch was specifically hypersensitive to excess Cu but not excess iron, zinc, or cadmium. The activities of antioxidant enzymes in atx1 and cchatx1 were markedly regulated in response to excess Cu, which confirms the phenotype of Cu hypersensitivity. Interestingly, atx1 and cchatx1 were sensitive to Cu deficiency. Overexpression of ATX1 not only enhanced Cu tolerance and accumulation in excess Cu conditions but also tolerance to Cu deficiency. In addition, the Cu-binding motif MXCXXC of ATX1 was required for these physiological functions. ATX1 was previously proposed to be involved in Cu homeostasis by its Cu-binding activity and interaction with the Cu transporter Heavy metal-transporting P-type ATPase5. In this study, we demonstrate that ATX1 plays an essential role in Cu homeostasis in conferring tolerance to excess Cu and Cu deficiency. The possible mechanism is discussed.

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Higher plants possess two different types of ATX1-like copper chaperones

Cited by 85 publications

References 20 publications

Towards Understanding Plant Response to Heavy Metal Stress

Towards Understanding Plant Response to Heavy Metal Stress

Arabidopsis NPCC6/NaKR1 Is a Phloem Mobile Metal Binding Protein Necessary for Phloem Function and Root Meristem Maintenance

Copper Chaperone Antioxidant Protein1 Is Essential for Copper Homeostasis

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