Disease relevance of ATPLC1

• A gene encoding a phosphatidylinositol-specific phospholipase C is induced by dehydration and salt stress in Arabidopsis thaliana [1].
• The recombinant AtPLC1 protein synthesized in Escherichia coli was able to hydrolyze phosphatidylinositol 4,5-bisphosphate and this activity was completely dependent on Ca2+, as observed also for mammalian PI-PLCs [1].

High impact information on ATPLC1

• Expression of the pleckstrin homology (PH)-domain of phospholipase C (PLC)-delta1, which binds specifically to PtdIns 4, 5-P2, inhibited pollen tube elongation [2].
• We propose that AtPLC1 plays a role in secondary ABA responses [3].
• In transgenic lines expressing the inducible AtPLC1 sense transgene, an increase in AtPLC1 expression was not sufficient to activate the expression of ABA-responsive genes in vegetative tissues [3].
• Our results indicate that although an increase in PLC1 activity and increased Ins(1,4,5)P3 levels are necessary for maximal gene induction by ABA, overexpression of AtPLC1 itself is not sufficient to trigger the expression of ABA-responsive genes [3].
• Arabidopsis PLC1 is required for secondary responses to abscisic acid signals [3].

Biological context of ATPLC1

• In the presence of the dexamethasone (Dex) inducer, transgenic lines expressing the AtPLC1 antisense and AtIP5PII sense transgenes showed no inhibition of germination and growth by ABA, whereas in the absence of the inducer they were sensitive [3].
• The promoter region contained two TATA-like elements at -43 and -185 and other putative regulatory elements that suggest that this PLC is hormonally regulated [4].
• The Arabidopsis thaliana genome has multiple divergent forms of phosphoinositol-specific phospholipase C1 [4].

Associations of ATPLC1 with chemical compounds

• In vitro experiments demonstrated the induced PLC1 expression when extracts were assayed in the presence of calcium, but no increase in Ins(1,4,5)P3 levels in vivo was detected, suggesting that the PLC1 enzyme was latent [3].
• This later wave of PA accumulation was several orders of magnitude higher than the PLC-dependent first wave [5].
• Using a variety of approaches, we show here that GCR1-enhanced thymidine incorporation into DNA depends on an increase in phosphatidylinositol-specific phospholipase C activity and an elevation of inositol 1,4,5-trisphosphate levels in the cells [6].
• This production was due to the simultaneous activation of phospholipase C (through diacylglycerol kinase activity) and phospholipase D, as monitored by the production of inositol triphosphate and of transphosphatidylation product, respectively [7].
• The role of these pathways in the cold response has been investigated by analyzing the transcriptome of cold-treated Arabidopsis (Arabidopsis thaliana) suspension cells in the presence of U73122 or ethanol, inhibitors of the PLC/diacylglycerol kinase pathway and of the phosphatidic acid produced by PLD, respectively [8].

Analytical, diagnostic and therapeutic context of ATPLC1

• Northern blot analysis showed that the AtPLC1 gene is expressed at very low levels in the plant under normal conditions but is induced to a significant extent under various environmental stresses, such as dehydration, salinity, and low temperature [1].
• Using one of the PCR clones, we isolated a corresponding full-length Arabidopsis PLC gene (ATHATPLC1G), and sequence analysis indicated that it was most like a delta-type PLC [4].

References