Limits...
Phosphate deprivation induces transfer of DGDG galactolipid from chloroplast to mitochondria.

Jouhet J, Maréchal E, Baldan B, Bligny R, Joyard J, Block MA - J. Cell Biol. (2004)

Bottom Line: Mitochondria do not synthesize this pool of DGDG, which structure is shown to be characteristic of a DGD type enzyme present in plastid envelope.This transfer does not apparently involve the endomembrane system and would rather be dependent upon contacts between plastids and mitochondria.Contacts sites are favored at early stages of phosphate deprivation when DGDG cell content is just starting to respond to phosphate deprivation.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire de Physiologie Cellulaire Végétale, UMR 5168 (CNRS/CEA/Université Jseph Fourier/INRA), DRDC-PCV, CEA-Grenoble, Grenoble, France.

ABSTRACT
In many soils plants have to grow in a shortage of phosphate, leading to development of phosphate-saving mechanisms. At the cellular level, these mechanisms include conversion of phospholipids into glycolipids, mainly digalactosyldiacylglycerol (DGDG). The lipid changes are not restricted to plastid membranes where DGDG is synthesized and resides under normal conditions. In plant cells deprived of phosphate, mitochondria contain a high concentration of DGDG, whereas mitochondria have no glycolipids in control cells. Mitochondria do not synthesize this pool of DGDG, which structure is shown to be characteristic of a DGD type enzyme present in plastid envelope. The transfer of DGDG between plastid and mitochondria is investigated and detected between mitochondria-closely associated envelope vesicles and mitochondria. This transfer does not apparently involve the endomembrane system and would rather be dependent upon contacts between plastids and mitochondria. Contacts sites are favored at early stages of phosphate deprivation when DGDG cell content is just starting to respond to phosphate deprivation.

Show MeSH

Related in: MedlinePlus

Immunoagglutination assays of isolated mitochondria prepared from either control or 3 d Pi-deprived A. thaliana cells. Mitochondria from Pi-deprived cells, control cells, and chloroplasts were incubated with antibodies as specified. Addition of anti-DGDG lead to agglutination of chloroplasts and of mitochondria of Pi-deprived cells only. Control antibodies were directed against E37 and OEP21 chloroplast inner and outer membrane protein, respectively, and TOM20 and TOM40 outer membrane mitochondrial proteins.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2172463&req=5

fig4: Immunoagglutination assays of isolated mitochondria prepared from either control or 3 d Pi-deprived A. thaliana cells. Mitochondria from Pi-deprived cells, control cells, and chloroplasts were incubated with antibodies as specified. Addition of anti-DGDG lead to agglutination of chloroplasts and of mitochondria of Pi-deprived cells only. Control antibodies were directed against E37 and OEP21 chloroplast inner and outer membrane protein, respectively, and TOM20 and TOM40 outer membrane mitochondrial proteins.

Mentions: Antibodies raised against DGDG were used to test a possible agglutination of purified mitochondria (Fig. 4). In absence of antibodies, control and −Pi purified mitochondria were visible under light microscope as nonaggregated, whereas they agglutinated in presence of antibodies against mitochondria outer membrane proteins TOM20 and TOM40. When antibodies raised against plastid proteins, like E37 and OEP21, were added to mitochondria, no agglutination was visible whenever OEP21 antibodies did induce chloroplast agglutination. With antibodies raised against DGDG, no agglutination of control mitochondria could be detected, but a strong agglutination was observed with mitochondria prepared from Pi-deprived cells. In conclusion, immunoagglutination assays indicated that in Pi-starved cells, DGDG is accessible on the mitochondrial outer surface to specific antibodies.


Phosphate deprivation induces transfer of DGDG galactolipid from chloroplast to mitochondria.

Jouhet J, Maréchal E, Baldan B, Bligny R, Joyard J, Block MA - J. Cell Biol. (2004)

Immunoagglutination assays of isolated mitochondria prepared from either control or 3 d Pi-deprived A. thaliana cells. Mitochondria from Pi-deprived cells, control cells, and chloroplasts were incubated with antibodies as specified. Addition of anti-DGDG lead to agglutination of chloroplasts and of mitochondria of Pi-deprived cells only. Control antibodies were directed against E37 and OEP21 chloroplast inner and outer membrane protein, respectively, and TOM20 and TOM40 outer membrane mitochondrial proteins.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2172463&req=5

fig4: Immunoagglutination assays of isolated mitochondria prepared from either control or 3 d Pi-deprived A. thaliana cells. Mitochondria from Pi-deprived cells, control cells, and chloroplasts were incubated with antibodies as specified. Addition of anti-DGDG lead to agglutination of chloroplasts and of mitochondria of Pi-deprived cells only. Control antibodies were directed against E37 and OEP21 chloroplast inner and outer membrane protein, respectively, and TOM20 and TOM40 outer membrane mitochondrial proteins.
Mentions: Antibodies raised against DGDG were used to test a possible agglutination of purified mitochondria (Fig. 4). In absence of antibodies, control and −Pi purified mitochondria were visible under light microscope as nonaggregated, whereas they agglutinated in presence of antibodies against mitochondria outer membrane proteins TOM20 and TOM40. When antibodies raised against plastid proteins, like E37 and OEP21, were added to mitochondria, no agglutination was visible whenever OEP21 antibodies did induce chloroplast agglutination. With antibodies raised against DGDG, no agglutination of control mitochondria could be detected, but a strong agglutination was observed with mitochondria prepared from Pi-deprived cells. In conclusion, immunoagglutination assays indicated that in Pi-starved cells, DGDG is accessible on the mitochondrial outer surface to specific antibodies.

Bottom Line: Mitochondria do not synthesize this pool of DGDG, which structure is shown to be characteristic of a DGD type enzyme present in plastid envelope.This transfer does not apparently involve the endomembrane system and would rather be dependent upon contacts between plastids and mitochondria.Contacts sites are favored at early stages of phosphate deprivation when DGDG cell content is just starting to respond to phosphate deprivation.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire de Physiologie Cellulaire Végétale, UMR 5168 (CNRS/CEA/Université Jseph Fourier/INRA), DRDC-PCV, CEA-Grenoble, Grenoble, France.

ABSTRACT
In many soils plants have to grow in a shortage of phosphate, leading to development of phosphate-saving mechanisms. At the cellular level, these mechanisms include conversion of phospholipids into glycolipids, mainly digalactosyldiacylglycerol (DGDG). The lipid changes are not restricted to plastid membranes where DGDG is synthesized and resides under normal conditions. In plant cells deprived of phosphate, mitochondria contain a high concentration of DGDG, whereas mitochondria have no glycolipids in control cells. Mitochondria do not synthesize this pool of DGDG, which structure is shown to be characteristic of a DGD type enzyme present in plastid envelope. The transfer of DGDG between plastid and mitochondria is investigated and detected between mitochondria-closely associated envelope vesicles and mitochondria. This transfer does not apparently involve the endomembrane system and would rather be dependent upon contacts between plastids and mitochondria. Contacts sites are favored at early stages of phosphate deprivation when DGDG cell content is just starting to respond to phosphate deprivation.

Show MeSH
Related in: MedlinePlus