Phospholipid Mediated Activation of Calcium Dependent Protein Kinase 1 (CaCDPK1) from Chickpea: A New Paradigm of Regulation

Ajay Kumar Dixit, Chelliah Jayabaskaran

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Phospholipids, the major structural components of membranes, can also have functions in regulating signaling pathways in plants under biotic and abiotic stress. The effects of adding phospholipids on the activity of stress-induced calcium dependent protein kinase (CaCDPK1) from chickpea are reported here. Both autophosphorylation as well as phosphorylation of the added substrate were enhanced specifically by phosphatidylcholine and to a lesser extent by phosphatidic acid, but not by phosphatidylethanolamine. Diacylgylerol, the neutral lipid known to activate mammalian PKC, stimulated CaCDPK1 but at higher concentrations. Increase in Vmax of the enzyme activity by these phospholipids significantly decreased the Km indicating that phospholipids enhance the affinity towards its substrate. In the absence of calcium, addition of phospholipids had no effect on the negligible activity of the enzyme. Intrinsic fluorescence intensity of the CaCDPK1 protein was quenched on adding PA and PC. Higher binding affinity was found with PC (K1/2 = 114 nM) compared to PA (K1/2 = 335 nM). We also found that the concentration of PA increased in chickpea plants under salt stress. The stimulation by PA and PC suggests regulation of CaCDPK1 by these phospholipids during stress response.

Original languageEnglish (US)
Article numbere51591
JournalPloS one
Volume7
Issue number12
DOIs
StatePublished - Dec 20 2012

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Cicer
protein kinases
Phospholipids
phospholipids
Chemical activation
calcium
Phosphatidic Acids
enzyme activity
Enzymes
Phosphorylation
Phosphatidylcholines
protein phosphorylation
Protein Kinase C
Enzyme activity
Substrates
phosphatidylethanolamines
biotic stress
phosphatidylcholines
Salts
abiotic stress

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Phospholipid Mediated Activation of Calcium Dependent Protein Kinase 1 (CaCDPK1) from Chickpea : A New Paradigm of Regulation. / Dixit, Ajay Kumar; Jayabaskaran, Chelliah.

In: PloS one, Vol. 7, No. 12, e51591, 20.12.2012.

Research output: Contribution to journalArticle

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