Extended Data Fig. 4: Quantitative phosphoproteomic analysis of the CEPH substrate.
From: A type 2C protein phosphatase activates high-affinity nitrate uptake by dephosphorylating NRT2.1
a, Mass spectra of the NRT2.1 G478 nonphosphorylated peptide (position 478-493 in NRT2.1 protein) derived from reciprocally 14N- and 15N-labeled plants, showing comparable NRT2.1 protein abundance in WT and ceph-1 plants. b, Mass spectra of the NRT2.1 T521 phosphopeptide (position 516-530 in NRT2.1) derived from reciprocally labeled plants, showing comparable phosphorylation levels in WT and ceph-1 plants. (c) Dephosphorylation of the NRT2.1 S28 phosphopeptide with CEPH-GFP detected by LC-MS in the selected ion monitoring mode at m/z 831.9.
