A Novel Phosphatidylcholine-hydrolyzing Phospholipase C Induced by Phosphate Starvation in Arabidopsis
During phosphate starvation, it is known that phospholipids are degraded, and conversely, a nonphosphorus galactolipid digalactosyldiacylglycerol accumulates in the root plasma membrane of plants. We report a novel phospholipase C that hydrolyzes phosphatidylcholine and is greatly induced in respons...
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Veröffentlicht in: | The Journal of biological chemistry 2005-03, Vol.280 (9), p.7469-7476 |
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Zusammenfassung: | During phosphate starvation, it is known that phospholipids are degraded, and conversely, a nonphosphorus galactolipid digalactosyldiacylglycerol
accumulates in the root plasma membrane of plants. We report a novel phospholipase C that hydrolyzes phosphatidylcholine and
is greatly induced in response to phosphate deprivation in Arabidopsis . Since phosphatidylcholine-hydrolyzing activity by phospholipase C was highly up-regulated in phosphate-deprived plants,
gene expression of some phospholipase C was expected to be induced during phosphate starvation. Based on amino acid sequence
similarity to a bacterial phosphatidylcholine-hydrolyzing phospholipase C, six putative phospholipase Cs were identified in
the Arabidopsis genome, one of which, NPC4 , showed significant transcriptional activation upon phosphate limitation. Molecular cloning and functional expression of
NPC4 confirmed that the NPC4 gene encoded a functional phosphatidylcholine-hydrolyzing phospholipase C that did not require Ca 2+ for its activity. Subcellular localization analysis showed that NPC4 protein was highly enriched in the plasma membrane.
Analyses of transferred DNA-tagged npc4 mutants revealed that disruption of NPC4 severely reduces the phosphatidylcholine-hydrolyzing phospholipase C activity in response to phosphate starvation. These
results suggest that NPC4 plays an important role in the supply of both inorganic phosphate and diacylglycerol from membrane-localized
phospholipids that would be used for phosphate supplementation and the replacement of polar lipids in the root plasma membrane
during phosphate deprivation. |
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ISSN: | 0021-9258 1083-351X |
DOI: | 10.1074/jbc.M408799200 |