A Novel Isoform of the Secretory Pathway Ca2+,Mn2+-ATPase, hSPCA2, Has Unusual Properties and Is Expressed in the Brain

Xiang, Minghui; Mohamalawari, Deepti R.; Rao, Rajini

doi:10.1074/jbc.m413116200

Cited by 108 publications

(122 citation statements)

References 38 publications

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“…hSPCA2 was shown to be expressed in neuronal cells. In contrast to the report of Xiang et al (17) we showed that hSPCA2 displays a high apparent affinity for Ca 2ϩ similar to those values documented for hSPCA1a expressed in yeast (11) and for hSPCA1d expressed in COS-1 cells (12). Furthermore the Ca 2ϩ -or Mn 2ϩ -dependent activation of phosphoenzyme formation with [␥- 32 P]ATP and the ability to pump both Ca 2ϩ and Mn 2ϩ were also demonstrated.…”

Section: ؉contrasting

confidence: 54%

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The Secretory Pathway Ca2+/Mn2+-ATPase 2 Is a Golgi-localized Pump with High Affinity for Ca2+ Ions

Vanoevelen

Dode

Baelen

et al. 2005

Journal of Biological Chemistry

121

124

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Section: ؉contrasting

confidence: 54%

“…The human genome also contains a second gene (ATP2C2) encoding a secretory pathway Ca 2ϩ /Mn 2ϩ -ATPase (hSPCA2) that has not been characterized except for a recent study published while the present work was submitted (17). This group revealed hSPCA2 as a Ca 2ϩ pump upon heterologous expression in yeast.…”

Section: ؉mentioning

confidence: 99%

The Secretory Pathway Ca2+/Mn2+-ATPase 2 Is a Golgi-localized Pump with High Affinity for Ca2+ Ions

Vanoevelen

Dode

Baelen

et al. 2005

Journal of Biological Chemistry

121

124

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“…In this pathway, secretory pathway Ca/Mn-ATPases are believed to confer Mn tolerance by sequestering the metal into secretory vesicles and subsequent exocytosis (31,37). Although analogous mechanisms have not yet been described for plants, our data regarding characterization of the Arabidopsis and poplar CDFs AtMTP11 and PtMTP11s strongly suggest that a similar strategy is used by plants.…”

Section: Discussionmentioning

confidence: 69%

A secretory pathway-localized cation diffusion facilitator confers plant manganese tolerance

Peiter

Montanini

Gobert

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

250

262

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Manganese toxicity is a major problem for plant growth in acidic soils, but cellular mechanisms that facilitate growth in such conditions have not been clearly delineated. Established mechanisms that counter metal toxicity in plants involve chelation and cytoplasmic export of the metal across the plasma or vacuolar membranes out of the cell or sequestered into a large organelle, respectively. We report here that expression of the Arabidopsis and poplar MTP11 cation diffusion facilitators in a manganesehypersensitive yeast mutant restores manganese tolerance to wild-type levels. Microsomes from yeast expressing AtMTP11 exhibit enhanced manganese uptake. In accord with a presumed function of MTP11 in manganese tolerance, Arabidopsis mtp11 mutants are hypersensitive to elevated levels of manganese, whereas plants overexpressing MTP11 are hypertolerant. In contrast, sensitivity to manganese deficiency is slightly decreased in mutants and increased in overexpressing lines. Promoter-GUS studies showed that AtMTP11 is most highly expressed in root tips, shoot margins, and hydathodes, but not in epidermal cells and trichomes, which are generally associated with manganese accumulation. Surprisingly, imaging of MTP11-EYFP fusions demonstrated that MTP11 localizes neither to the plasma membrane nor to the vacuole, but to a punctate endomembrane compartment that largely coincides with the distribution of the trans-Golgi marker sialyl transferase. Golgi-based manganese accumulation might therefore result in manganese tolerance through vesicular trafficking and exocytosis. In accord with this proposal, Arabidopsis mtp11 mutants exhibit enhanced manganese concentrations in shoots and roots. We propose that Golgi-mediated exocytosis comprises a conserved mechanism for heavy metal tolerance in plants.Golgi ͉ heavy metal transport ͉ metal tolerance protein ͉ metal trafficking ͉ manganese transporter T ransition metals are required by living systems where they perform a wide variety of functions as cofactors for enzymes and transcription factors. Transition metals are also present in many environments at potentially toxic concentrations, and this has led to the evolution of mechanisms that counter toxicity. In plants exposed to high concentrations of transition metals in the soil, binding of the metals to phytochelatins in the cytosol lowers metal activity (1). Additionally, metals can be removed from the cytosol through the action of metal transporters. Transporters involved in metal tolerance localize to the plasma membrane, thereby removing metals from the cell, or to the vacuolar membrane, where the metal can be sequestered into a large and metabolically relatively inert intracellular compartment (2).Manganese is the second most prevalent transition metal, after iron, in the Earth's crust and an essential micronutrient for all organisms, including humans and plants (3). In addition to being a cofactor for a variety of enzymes (including various decarboxylases of the tricarboxylic acid cycle, RNA polymerases, and numerous glyco...

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“…28 Secretory pathway Ca/Mn-ATPases which are localized on Golgi or trans-Golgi network (TGN) serve a physiological role in the sequestration of manganese into secretory vesicles and subsequent release of manganese. 29 Recently, yeast Ca-ATPase, Pmr1p, was also demonstrated to play a central role in the secretion of cadmium through the secretory pathway. 30 Similar mechanism has now been reported in plants.…”

Section: Cadmium and Vesicular Traffickingmentioning

confidence: 99%

Cadmium toxicity

Wan

Zhang

2012

Plant Signaling & Behavior

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A Novel Isoform of the Secretory Pathway Ca2+,Mn2+-ATPase, hSPCA2, Has Unusual Properties and Is Expressed in the Brain

Cited by 108 publications

References 38 publications

The Secretory Pathway Ca2+/Mn2+-ATPase 2 Is a Golgi-localized Pump with High Affinity for Ca2+ Ions

The Secretory Pathway Ca2+/Mn2+-ATPase 2 Is a Golgi-localized Pump with High Affinity for Ca2+ Ions

A secretory pathway-localized cation diffusion facilitator confers plant manganese tolerance

Cadmium toxicity

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