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. Author manuscript; available in PMC: 2019 Jun 1.
Published in final edited form as: Heart Rhythm. 2018 Feb 2;15(6):895–904. doi: 10.1016/j.hrthm.2018.01.024

Figure 1.

Figure 1

(A) Phosphorylation status of KCNQ1 carboxy terminus in HEK 293 cells (co-expressing KCNQ1 and KCNE1) following treatment with 100 nM ISO for 3 minutes, 4 hours, and 24 hours via LCMS/MS analysis. (B) Peptide fragments corresponding to the intracellular regions of KCNQ1 were exposed to activated δCaMKII for 4 minutes and 30 seconds. Each peptide was 15 amino acids in length, tiled by two residues for 13 overlapping residues per consecutive peptide. Peptide fragments containing residues T482 and S484 (solid box at D5-D7) were the strongest substrates for CaMKII phosphorylation. The dashed box at D5-D7 is following 30 second exposure of activated δCaMKII. The solid box (F15-F19) contains a autocamtide-2 negative control (T→A mutation; F15), WT autocamtide-2 positive control (F17), and kemptide control (classical PKA substrate; F19). Full peptide sequences are in Supplemental Table 1. (C) Schematic of KCNQ1 and KCNE1 subunits showing carboxy terminal sites of potential CaMKII regulation investigated. *p<0.05 vs. control