Identification of phosphorylation site of an Arabidopsis CNGC by a calcium-dependent protein kinase with TiO_(2) column enrichment and mass spectrometry

摘要

Arabidopsis (Arabidopsis thaliana) genorne encodes 34 calcium-dependent protein kinases (CDPKs) and eight CDPK-related kinases (CRKs). These protein kinases have been shown to phosphorylate different substrates in plant cells. We examined the phosphorylation site of a putative substrate, cyclic nucleotide-gated channel (CNGC), phosphorylated by a type of calcium-dependent protein kinase by use of mass spectrometry and neutral loss method. Phosphorylation was further confirmed by radiolabelled kinase assay. In addition, we utilized titanium column (TiO_(2)) to enrich the phosphorylated peptides prior to mass spectrometric analysis.