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Targeting of Cameleons to various subcellular compartments reveals a strict cytoplasmic/mitochondrial Ca 2+ handling relationship in plant cells
Author(s) -
Loro Giovanna,
Drago Ilaria,
Pozzan Tullio,
Schiavo Fiorella Lo,
Zottini Michela,
Costa Alex
Publication year - 2012
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2012.04968.x
Subject(s) - cytoplasm , mitochondrion , cytosol , microbiology and biotechnology , biology , biophysics , nucleus , biochemistry , enzyme
Summary Here we describe use of a mitochondrial targeted Cameleon to produce stably transformed Arabidopsis plants that enable analyses of mitochondrial Ca 2+ dynamics in planta and allow monitoring of the intra‐mitochondrial Ca 2+ concentration in response to physiological or environmental stimuli. Transgenic plants co‐expressing nuclear and mitochondrial targeted Cameleons were also generated and analyzed. Here we show that mitochondrial Ca 2+ accumulation is strictly related to the intensity of the cytoplasmic Ca 2+ increase, demonstrating a tight association between mitochondrial and cytoplasmic Ca 2+ dynamics. However, under all experimental conditions, mitochondrial Ca 2+ dynamics were substantially different from those monitored in the cytoplasm, demonstrating that mitochondria do not passively sense cytosolic Ca 2+ , but actively modulate the intra‐mitochondrial level of the cation. In particular, our analyses show that the kinetics of Ca 2+ release from mitochondria are much slower than in the cytoplasm and nucleus. The mechanisms and functional implications of these differences are discussed.