Bohannon BM , de la Cruz A , Wu X , Jowais JJ , Perez ME , Dykxhoorn DM , Liin SI , Larsson HP .

R01-HL131461 NIH HHS , 2017-02040 Swedish Research Council, R01 HL131461 NHLBI NIH HHS

	Figure 1- PUFA analogue, Linoleoyl-taurine, activates Kv7.1/KCNE1 channels through an electrostatic mechanism on voltage sensor and pore. (A) Simplified membrane topology of a single Kv7.1 α-subunit (blue) and a single KCNE1 β-subunit (grey). (B) Voltage protocol used to measure voltage dependence of activation and representative Kv7.1/KCNE1 current traces in control (0 μM) and 20 μM Lin-taurine. Arrows mark tail currents. (C) Current-voltage relationship demonstrating PUFA analogue-induced left-shift in the voltage-dependence of activation (V0.5) and increase in maximal conductance (Gmax) (mean ± SEM; n = 3). (D) Model in which PUFA analogues with their negatively charged head groups insert in the cell membrane close to the positively charged arginines in the voltage sensor S4 and close to a positively charged lysine in the pore. The PUFA thereby exerts an electrostatic effect on the voltage sensor to shift the voltage dependence of activation and an electrostatic effect on the pore to increase the maximum conductance (Liin et al., 2018a).
	Figure 2- PUFA analogue, Linoleoyl-taurine, inhibits Cav1.2/β3/α2δ channels without altering channel voltage dependence. (A) Simplified membrane topology of the Cav1.2 pore-forming α-subunit (light gray) and auxiliary β- (mint) and α2δ-subunits (yellow and green). (B) Voltage protocol used to measure voltage dependence of activation and representative Cav1.2/β3/α2δ current traces in control (0 μM) and 20 μM Lin-taurine. (C) Current-voltage relationship demonstrating dose-dependent inhibition of Cav1.2/β3/α2δ currents measured from activation protocol (mean ± SEM; n = 5). (D) Voltage protocol used to measure voltage dependence of inactivation and representative Cav1.2/β3/α2δ current traces in control (0 μM) and 20 μM Lin-taurine measured at arrow. (E) Current-voltage relationship demonstrating dose-dependent inhibition of Cav1.2/β3/α2δ currents measured from inactivation protocol (mean ± SEM; n = 5). See Figure 2—figure supplement 1 for comparison with effects on Cav1.2/β2/α2δ.
	Figure 3- PUFA analogue, Linoleoyl-taurine, inhibits Nav1.5/β1 by shifting the voltage dependence of inactivation. (A) Simplified membrane topology of the Nav1.5 pore-forming α-subunit (light blue) and auxiliary β-subunit (green). (B) Voltage protocol used to measure voltage dependence of activation and representative Nav1.5/β1 current traces in control (0 μM) and 20 μM Lin-taurine. (C) Current-voltage relationship demonstrating dose-dependent inhibition of Nav1.5/β1 currents measured from activation protocol (mean ± SEM; n = 5). (D) Voltage protocol used to measure voltage dependence of inactivation and representative Nav1.5/β1 current traces in control (0 μM) and 20 μM Lin-taurine measured at arrow. (E) Current-voltage relationship demonstrating dose-dependent inhibition of Nav1.5/β1 currents and leftward shift in the voltage dependence of inactivation measured from inactivation protocol (mean ± SEM; n = 5).
	Figure 4- PUFA analogues with taurine head groups have the tendency to broadly modulate Kv7.1/KCNE1, Cav1.2/β3/α2δ, and Nav1.5/β1 channels. Structures for PUFA analogues with taurine head groups: Lin-taurine, N-AT, Pin-taurine, and DHA-taurine (top). (A–B) Dose dependent shifts in the (A) voltage dependence of activation (ΔV0.5) and (B) changes in maximal conductance (Gmax) for Kv7.1/KCNE1 induced by Lin-taurine (black squares; n = 3; mean ± SEM), N-AT (red circles; n = 5; mean ± SEM), Pin-taurine (green triangles; n = 4; mean ± SEM), and DHA-taurine (blue triangles; n = 3; mean ± SEM). (C–D) Dose dependent shifts in the (C) voltage dependence of inactivation (ΔV0.5) and (D) changes in maximal conductance (Gmax) for Cav1.2/β3/α2δ induced by Lin-taurine (black squares; n = 3; mean ± SEM), N-AT (red circles; n = 3; mean ± SEM), Pin-taurine (green triangles; n = 5; mean ± SEM), and DHA-taurine (blue triangles; n = 3; mean ± SEM). (E–F) Dose dependent shifts in the (E) voltage dependence of inactivation (ΔV0.5) and (F) changes in maximal conductance (Gmax) for Nav1.5/β1 induced by Lin-taurine (black squares; n = 3; mean ± SEM), N-AT (red circles; n = 3; mean ± SEM), Pin-taurine (green triangles; n = 4; mean ± SEM), and DHA-taurine (blue triangles; n = 3; mean ± SEM). See Figure 4—figure supplements 1–6 for more details.
	Figure 5- PUFA analogues with glycine head groups tend to be more selective for Kv7.1/KCNE1 than Cav1.2/β3/α2δ and Nav1.5/β1 channels. Structures for PUFA analogues with glycine head group: Lin-glycine, Pin-glycine, and DHA-glycine (top). (A–B) Dose dependent shifts in the (A) voltage dependence of activation (ΔV0.5) and (B) changes in maximal conductance (Gmax) for Kv7.1/KCNE1 induced by Lin-glycine (black squares; n = 4; mean ± SEM), Pin-glycine (red circles; n = 3; mean ± SEM), and DHA-glycine (green triangles; n = 4; mean ± SEM). (C–D) Dose dependent shifts in the (C) voltage dependence of inactivation (ΔV0.5) and (D) changes in maximal conductance (Gmax) for Cav1.2/β3/α2δ induced by Lin-glycine (black squares; n = 4; mean ± SEM), Pin-glycine (red circles; n = 3; mean ± SEM), and DHA-glycine (green triangles; n = 3; mean ± SEM). (E–F) Dose dependent shifts in the (E) voltage dependence of inactivation (ΔV0.5) and (F) changes in maximal conductance (Gmax) for Nav1.5/β1 induced by Lin-glycine (black squares; n = 4; mean ± SEM), Pin-glycine (red circles; n = 4; mean ± SEM), and DHA-glycine (green triangles; n = 7; mean ± SEM). See Figure 4—figure supplements 1–6 for more details.
	Figure 6- Dose response curves for PUFAs on IKs, ICaL, and INaV at 0 mV. Dose response of IKs, ICaL, and INaV currents (I/I0) at 0 mV for (A) Lin-taurine (Km of IKs = 11.4 ± 0.4 μM; Km of ICaL = 1.4 ± 0.4 μM; Km of INaV = 2.4 ± 0.04 μM; mean ± SEM), (B) N-AT (Km of IKs = NA; Km of ICaL = 2.5 ± 1.9 μM; Km of INaV = 3.1 ± 0.3 μM; mean ± SEM), (C) Pin-taurine (Km of IKs = 4.5 ± 0.2 μM; Km of ICaL = NA; Km of INaV = 5.8 ± 1.7 μM; mean ± SEM), (D) DHA-taurine (Km of IKs = 5.9 ± 0.3 μM; Km of ICaL >20 μM; Km of INaV = 2.3 ± 0.1 μM; mean ± SEM), (E) Lin-glycine (Km of IKs = 5.4 ± 0.2 μM; Km of ICaL = NA; Km of INaV = 5.6 ± 0.5 μM; mean ± SEM), (F) Pin-glycine (Km of IKs > 20 μM; Km of ICaL = NA; Km of INaV >20 μM; mean ± SEM), and (G) DHA-glycine (Km of IKs > 20 μM; Km of ICaL = NA; Km of INaV >20 μM; mean ± SEM),.
	Figure 7- PUFAs that are selective for Kv7.1/KCNE1 channels partially restore prolonged ventricular action potential and suppress early afterdepolarizations in cardiomyocyte simulations. (A–G) Simulated ventricular action potential in wild type cardiomyocytes (black) and in the presence of (A) 0.7 (red), 2 (green), and 7 μM N-AT (blue), (B) 0.7 (red), 2 (green), and 7 μM lin-taurine (blue), (C) 0.7 (red), 2 (green), and 7 μM pin-taurine (blue), (D) 0.7 (red), 2 (green), and 7 μM DHA-taurine (blue), (E) 0.7 (red), 2 (green), and 7 μM lin-glycine (blue), (F) 7 μM pin-glycine (blue solid), following 25% hERG block (red) and in the presence of 7 μM pin-glycine under 25% hERG block (blue dashed), and (G) 7 μM DHA-glycine (blue solid), following 25% hERG block (red) and in the presence of 7 μM DHA-glycine under 25% hERG block (blue dashed). (H) Early afterdepolarizations induced by dofetilide application (red) and suppression of early afterdepolarizations by 7 μM DHA-glycine in the presence of dofetilide (black). See Figure 7—figure supplement 1 for rate dependence of the effects.
	Figure 8- DHA-glycine decreases the APD90c of hiPSC cardiomyocytes. (A) Normalized representative CaT optical traces before (black) and after applied (red) 30 µM DHA-glycine on a monolayer of hiPSC-CM. (B) APD90c (ms) value in control conditions (black) and after applied (red) 30 µM DHA-glycine on hiPSC-CM (mean ± SEM; n = 3). *p<0.05.
	Supplementary figure 1- PUFA-induced effects on Cav1.2 expressed with β-subunit β2 and α2δ (Cav1.2/β2/α2δ). (A) Voltage dependence of activation for Cav1.2/β2/α2δ in the presence of Lin-taurine. (B) Voltage dependence of inactivation for Cav1.2/β2/α2δ in the presence of Lin-taurine. (C–D) Comparison between the voltage dependence of activation for (C) Cav1.2/β3/α2δ and (D) Cav1.2/β2/α2δ in the presence of Lin-glycine.
	Supplementary figure 2- Raw current traces for PUFA analogues on Kv7.1/KCNE1. Kv7.1/KCNE1 raw current traces in control (0 μM) (left) and 20 μM (middle) PUFA analogues, followed by current-voltage (I–V) relationship (right) for each PUFA analogue tested. Voltage protocol (top) overlaps with current traces to illustrate time points during the voltage steps. Arrows over top trace represent the point at which tail currents are measured for generation of current-voltage (I–V) relationship. Red traces represent the current that occurs at a voltage step to 20 mV.
	Supplementary figure 3- Raw current traces for PUFA analogues on Cav1.2/β3/α2δ. Cav1.2/β3/α2δ raw current traces in control (0 μM) (top trace for each PUFA analogue) and 20 μM (bottom trace for each PUFA analogue), followed by current-voltage (I–V) relationship (right) of voltage dependent activation for each PUFA analogue tested. Voltage protocol (top) overlaps with current traces to illustrate time points during the voltage steps. Red traces represent the voltage step that elicits peak current.
	Supplementary figure 4- PUFA-induced changes in I/I0 normalized by concentration show no changes in voltage-dependent activation of Cav1.2/β3/α2δ and Nav1.5/β1 channels. (A–B) Voltage-dependent activation of Cav1.2/β3/α2δ in the presence of (A) N-AT (n = 3) and (B) DHA-glycine (n = 3). Peak currents are normalized to each concentration to clearly visualize that there is no shifts in voltage-dependent activation. (C–D) Voltage-dependent activation of Nav1.5/β1 in the presence of (C) N-AT (n = 3) and (D) DHA-glycine (n = 7). Peak currents are normalized to each concentration to clearly visualize that there are no shifts in voltage-dependent activation.
	Supplementary figure 5- Internally normalized steady state inactivation curves for Cav1.2/β3/α2δ. (A–G) PUFA-induced effects on Nav1.5/β1 voltage dependent inactivation normalized by each concentration for: (A) Lin-taurine, (B) N-AT, (C) Pin-taurine, (D) DHA-taurine, (E) Lin-glycine, (F) Pin-glycine, and (G) DHA-glycine.
	Supplementary figure 6- Raw current traces for PUFA analogues on Nav1.5/β1 channels. Nav1.5/β1 raw current traces in control (0 μM) (top trace for each PUFA analogue) and 20 μM (bottom trace for each PUFA analogue) of applied PUFA analogues, followed by current-voltage (I–V) relationship for voltage dependent activation (middle) and I-V relationship for voltage dependent inactivation (right) for each PUFA analogue tested. Voltage protocol (top) overlaps with current traces to illustrate time points during the voltage steps. Red traces represent the voltage step that elicits peak current.
	Supplementary figure 7- Internally normalized steady state inactivation curves for Nav1.5/β1. (A–G) PUFA-induced effects on Nav1.5/β1 voltage dependent inactivation normalized by each concentration for: (A) Lin-taurine, (B) N-AT, (C) Pin-taurine, (D) DHA-taurine, (E) Lin-glycine, (F) Pin-glycine, and (G) DHA-glycine.
	Supplementary figure 8- Rate dependence of the simulated ventricular action potential and effects of DHA-glycine. (A) Simulations of the ventricular action potential at 40 bpm in control conditions (black) and simulated effects of 7 µM DHA-glycine (blue dashed line). (B) Simulations of the ventricular action potential at 60 bpm in control conditions (black) and simulated effects of 7 µM DHA-glycine (red dashed line). (C) Simulations of the ventricular action potential at 200 bpm in control conditions (black) and simulated effects of 7 µM DHA-glycine (magenta dashed line).
	Supplementary figure 9- Rate dependence of the IKs current during simulated ventricular action potentials and effects of DHA-glycine. (A) Simulations of the IKs current during the ventricular action potential at 40 bpm in control conditions (black line) and in 7 µM DHA-glycine (dark blue line). (B) Simulations of the IKs current during the ventricular action potential at 60 bpm in control conditions (black) and in 7 µM DHA-glycine (red dashed line). (C) Simulations of the IKs current during the ventricular action potential at 200 bpm in control conditions (black) and in 7 µM DHA-glycine (magenta dashed line). (D) IKs currents during simulation of the ventricular action potential at 200 bpm in control conditions after the indicated number of beats.
	Figure 1. PUFA analogue, Linoleoyl-taurine, activates Kv7.1/KCNE1 channels through an electrostatic mechanism on voltage sensor and pore.(A) Simplified membrane topology of a single Kv7.1 α-subunit (blue) and a single KCNE1 β-subunit (grey). (B) Voltage protocol used to measure voltage dependence of activation and representative Kv7.1/KCNE1 current traces in control (0 μM) and 20 μM Lin-taurine. Arrows mark tail currents. (C) Current-voltage relationship demonstrating PUFA analogue-induced left-shift in the voltage-dependence of activation (V0.5) and increase in maximal conductance (Gmax) (mean ± SEM; n = 3). (D) Model in which PUFA analogues with their negatively charged head groups insert in the cell membrane close to the positively charged arginines in the voltage sensor S4 and close to a positively charged lysine in the pore. The PUFA thereby exerts an electrostatic effect on the voltage sensor to shift the voltage dependence of activation and an electrostatic effect on the pore to increase the maximum conductance (Liin et al., 2018a).Figure 1—source data 1. Effects of lin-taurine on cardiac ion channels.
	Figure 2. PUFA analogue, Linoleoyl-taurine, inhibits Cav1.2/β3/α2δ channels without altering channel voltage dependence.(A) Simplified membrane topology of the Cav1.2 pore-forming α-subunit (light gray) and auxiliary β- (mint) and α2δ-subunits (yellow and green). (B) Voltage protocol used to measure voltage dependence of activation and representative Cav1.2/β3/α2δ current traces in control (0 μM) and 20 μM Lin-taurine. (C) Current-voltage relationship demonstrating dose-dependent inhibition of Cav1.2/β3/α2δ currents measured from activation protocol (mean ± SEM; n = 5). (D) Voltage protocol used to measure voltage dependence of inactivation and representative Cav1.2/β3/α2δ current traces in control (0 μM) and 20 μM Lin-taurine measured at arrow. (E) Current-voltage relationship demonstrating dose-dependent inhibition of Cav1.2/β3/α2δ currents measured from inactivation protocol (mean ± SEM; n = 5). See Figure 2—figure supplement 1 for comparison with effects on Cav1.2/β2/α2δ.Figure 2—figure supplement 1. PUFA-induced effects on Cav1.2 expressed with β-subunit β2 and α2δ (Cav1.2/β2/α2δ).(A) Voltage dependence of activation for Cav1.2/β2/α2δ in the presence of Lin-taurine. (B) Voltage dependence of inactivation for Cav1.2/β2/α2δ in the presence of Lin-taurine. (C–D) Comparison between the voltage dependence of activation for (C) Cav1.2/β3/α2δ and (D) Cav1.2/β2/α2δ in the presence of Lin-glycine.
	Figure 3. PUFA analogue, Linoleoyl-taurine, inhibits Nav1.5/β1 by shifting the voltage dependence of inactivation.(A) Simplified membrane topology of the Nav1.5 pore-forming α-subunit (light blue) and auxiliary β-subunit (green). (B) Voltage protocol used to measure voltage dependence of activation and representative Nav1.5/β1 current traces in control (0 μM) and 20 μM Lin-taurine. (C) Current-voltage relationship demonstrating dose-dependent inhibition of Nav1.5/β1 currents measured from activation protocol (mean ± SEM; n = 5). (D) Voltage protocol used to measure voltage dependence of inactivation and representative Nav1.5/β1 current traces in control (0 μM) and 20 μM Lin-taurine measured at arrow. (E) Current-voltage relationship demonstrating dose-dependent inhibition of Nav1.5/β1 currents and leftward shift in the voltage dependence of inactivation measured from inactivation protocol (mean ± SEM; n = 5).
	Figure 4. PUFA analogues with taurine head groups have the tendency to broadly modulate Kv7.1/KCNE1, Cav1.2/β3/α2δ, and Nav1.5/β1 channels.Structures for PUFA analogues with taurine head groups: Lin-taurine, N-AT, Pin-taurine, and DHA-taurine (top). (A–B) Dose dependent shifts in the (A) voltage dependence of activation (ΔV0.5) and (B) changes in maximal conductance (Gmax) for Kv7.1/KCNE1 induced by Lin-taurine (black squares; n = 3; mean ± SEM), N-AT (red circles; n = 5; mean ± SEM), Pin-taurine (green triangles; n = 4; mean ± SEM), and DHA-taurine (blue triangles; n = 3; mean ± SEM). (C–D) Dose dependent shifts in the (C) voltage dependence of inactivation (ΔV0.5) and (D) changes in maximal conductance (Gmax) for Cav1.2/β3/α2δ induced by Lin-taurine (black squares; n = 3; mean ± SEM), N-AT (red circles; n = 3; mean ± SEM), Pin-taurine (green triangles; n = 5; mean ± SEM), and DHA-taurine (blue triangles; n = 3; mean ± SEM). (E–F) Dose dependent shifts in the (E) voltage dependence of inactivation (ΔV0.5) and (F) changes in maximal conductance (Gmax) for Nav1.5/β1 induced by Lin-taurine (black squares; n = 3; mean ± SEM), N-AT (red circles; n = 3; mean ± SEM), Pin-taurine (green triangles; n = 4; mean ± SEM), and DHA-taurine (blue triangles; n = 3; mean ± SEM). See Figure 4—figure supplements 1–6 for more details.Figure 4—source data 1. Effects of N-AT on cardiac ion channels.Figure 4—source data 2. Effects of pin-taurine on cardiac ion channels.Figure 4—source data 3. Effects of DHA-taurine on cardiac ion channels.Figure 4—figure supplement 1. Raw current traces for PUFA analogues on Kv7.1/KCNE1.Kv7.1/KCNE1 raw current traces in control (0 μM) (left) and 20 μM (middle) PUFA analogues, followed by current-voltage (I–V) relationship (right) for each PUFA analogue tested. Voltage protocol (top) overlaps with current traces to illustrate time points during the voltage steps. Arrows over top trace represent the point at which tail currents are measured for generation of current-voltage (I–V) relationship. Red traces represent the current that occurs at a voltage step to 20 mV.
	Figure 4—figure supplement 2. Raw current traces for PUFA analogues on Cav1.2/β3/α2δ.Cav1.2/β3/α2δ raw current traces in control (0 μM) (top trace for each PUFA analogue) and 20 μM (bottom trace for each PUFA analogue), followed by current-voltage (I–V) relationship (right) of voltage dependent activation for each PUFA analogue tested. Voltage protocol (top) overlaps with current traces to illustrate time points during the voltage steps. Red traces represent the voltage step that elicits peak current.
	Figure 4—figure supplement 3. PUFA-induced changes in I/I0 normalized by concentration show no changes in voltage-dependent activation of Cav1.2/β3/α2δ and Nav1.5/β1 channels.(A–B) Voltage-dependent activation of Cav1.2/β3/α2δ in the presence of (A) N-AT (n = 3) and (B) DHA-glycine (n = 3). Peak currents are normalized to each concentration to clearly visualize that there is no shifts in voltage-dependent activation. (C–D) Voltage-dependent activation of Nav1.5/β1 in the presence of (C) N-AT (n = 3) and (D) DHA-glycine (n = 7). Peak currents are normalized to each concentration to clearly visualize that there are no shifts in voltage-dependent activation.
	Figure 4—figure supplement 4. Internally normalized steady state inactivation curves for Cav1.2/β3/α2δ.(A–G) PUFA-induced effects on Nav1.5/β1 voltage dependent inactivation normalized by each concentration for: (A) Lin-taurine, (B) N-AT, (C) Pin-taurine, (D) DHA-taurine, (E) Lin-glycine, (F) Pin-glycine, and (G) DHA-glycine.
	Figure 4—figure supplement 5. Raw current traces for PUFA analogues on Nav1.5/β1 channels.Nav1.5/β1 raw current traces in control (0 μM) (top trace for each PUFA analogue) and 20 μM (bottom trace for each PUFA analogue) of applied PUFA analogues, followed by current-voltage (I–V) relationship for voltage dependent activation (middle) and I-V relationship for voltage dependent inactivation (right) for each PUFA analogue tested. Voltage protocol (top) overlaps with current traces to illustrate time points during the voltage steps. Red traces represent the voltage step that elicits peak current.
	Figure 4—figure supplement 6. Internally normalized steady state inactivation curves for Nav1.5/β1.(A–G) PUFA-induced effects on Nav1.5/β1 voltage dependent inactivation normalized by each concentration for: (A) Lin-taurine, (B) N-AT, (C) Pin-taurine, (D) DHA-taurine, (E) Lin-glycine, (F) Pin-glycine, and (G) DHA-glycine.
	Figure 5. PUFA analogues with glycine head groups tend to be more selective for Kv7.1/KCNE1 than Cav1.2/β3/α2δ and Nav1.5/β1 channels.Structures for PUFA analogues with glycine head group: Lin-glycine, Pin-glycine, and DHA-glycine (top). (A–B) Dose dependent shifts in the (A) voltage dependence of activation (ΔV0.5) and (B) changes in maximal conductance (Gmax) for Kv7.1/KCNE1 induced by Lin-glycine (black squares; n = 4; mean ± SEM), Pin-glycine (red circles; n = 3; mean ± SEM), and DHA-glycine (green triangles; n = 4; mean ± SEM). (C–D) Dose dependent shifts in the (C) voltage dependence of inactivation (ΔV0.5) and (D) changes in maximal conductance (Gmax) for Cav1.2/β3/α2δ induced by Lin-glycine (black squares; n = 4; mean ± SEM), Pin-glycine (red circles; n = 3; mean ± SEM), and DHA-glycine (green triangles; n = 3; mean ± SEM). (E–F) Dose dependent shifts in the (E) voltage dependence of inactivation (ΔV0.5) and (F) changes in maximal conductance (Gmax) for Nav1.5/β1 induced by Lin-glycine (black squares; n = 4; mean ± SEM), Pin-glycine (red circles; n = 4; mean ± SEM), and DHA-glycine (green triangles; n = 7; mean ± SEM). See Figure 4—figure supplements 1–6 for more details.Figure 5—source data 1. Effects of lin-glycine on cardiac ion channels.Figure 5—source data 2. Effects of pin-glycine on cardiac ion channels.Figure 5—source data 3. Effects of DHA-glycine on cardiac ion channels.
	Figure 6. Dose response curves for PUFAs on IKs, ICaL, and INaV at 0 mV.Dose response of IKs, ICaL, and INaV currents (I/I0) at 0 mV for (A) Lin-taurine (Km of IKs = 11.4 ± 0.4 μM; Km of ICaL = 1.4 ± 0.4 μM; Km of INaV = 2.4 ± 0.04 μM; mean ± SEM), (B) N-AT (Km of IKs = NA; Km of ICaL = 2.5 ± 1.9 μM; Km of INaV = 3.1 ± 0.3 μM; mean ± SEM), (C) Pin-taurine (Km of IKs = 4.5 ± 0.2 μM; Km of ICaL = NA; Km of INaV = 5.8 ± 1.7 μM; mean ± SEM), (D) DHA-taurine (Km of IKs = 5.9 ± 0.3 μM; Km of ICaL >20 μM; Km of INaV = 2.3 ± 0.1 μM; mean ± SEM), (E) Lin-glycine (Km of IKs = 5.4 ± 0.2 μM; Km of ICaL = NA; Km of INaV = 5.6 ± 0.5 μM; mean ± SEM), (F) Pin-glycine (Km of IKs > 20 μM; Km of ICaL = NA; Km of INaV >20 μM; mean ± SEM), and (G) DHA-glycine (Km of IKs > 20 μM; Km of ICaL = NA; Km of INaV >20 μM; mean ± SEM),.
	Figure 7. PUFAs that are selective for Kv7.1/KCNE1 channels partially restore prolonged ventricular action potential and suppress early afterdepolarizations in cardiomyocyte simulations.(A–G) Simulated ventricular action potential in wild type cardiomyocytes (black) and in the presence of (A) 0.7 (red), 2 (green), and 7 μM N-AT (blue), (B) 0.7 (red), 2 (green), and 7 μM lin-taurine (blue), (C) 0.7 (red), 2 (green), and 7 μM pin-taurine (blue), (D) 0.7 (red), 2 (green), and 7 μM DHA-taurine (blue), (E) 0.7 (red), 2 (green), and 7 μM lin-glycine (blue), (F) 7 μM pin-glycine (blue solid), following 25% hERG block (red) and in the presence of 7 μM pin-glycine under 25% hERG block (blue dashed), and (G) 7 μM DHA-glycine (blue solid), following 25% hERG block (red) and in the presence of 7 μM DHA-glycine under 25% hERG block (blue dashed). (H) Early afterdepolarizations induced by dofetilide application (red) and suppression of early afterdepolarizations by 7 μM DHA-glycine in the presence of dofetilide (black). See Figure 7—figure supplement 1 for rate dependence of the effects.Figure 7—figure supplement 1. Rate dependence of the simulated ventricular action potential and effects of DHA-glycine.(A) Simulations of the ventricular action potential at 40 bpm in control conditions (black) and simulated effects of 7 µM DHA-glycine (blue dashed line). (B) Simulations of the ventricular action potential at 60 bpm in control conditions (black) and simulated effects of 7 µM DHA-glycine (red dashed line). (C) Simulations of the ventricular action potential at 200 bpm in control conditions (black) and simulated effects of 7 µM DHA-glycine (magenta dashed line).
	Figure 7—figure supplement 2. Rate dependence of the IKs current during simulated ventricular action potentials and effects of DHA-glycine.(A) Simulations of the IKs current during the ventricular action potential at 40 bpm in control conditions (black line) and in 7 µM DHA-glycine (dark blue line). (B) Simulations of the IKs current during the ventricular action potential at 60 bpm in control conditions (black) and in 7 µM DHA-glycine (red dashed line). (C) Simulations of the IKs current during the ventricular action potential at 200 bpm in control conditions (black) and in 7 µM DHA-glycine (magenta dashed line). (D) IKs currents during simulation of the ventricular action potential at 200 bpm in control conditions after the indicated number of beats.
	Figure 8. DHA-glycine decreases the APD90c of hiPSC cardiomyocytes.(A) Normalized representative CaT optical traces before (black) and after applied (red) 30 µM DHA-glycine on a monolayer of hiPSC-CM. (B) APD90c (ms) value in control conditions (black) and after applied (red) 30 µM DHA-glycine on hiPSC-CM (mean ± SEM; n = 3). *p<0.05.

Ahern, The hitchhiker's guide to the voltage-gated sodium channel galaxy. 2016, Pubmed

Ahern, The hitchhiker's guide to the voltage-gated sodium channel galaxy. 2016, Pubmed
Ahuja, Structural basis of Nav1.7 inhibition by an isoform-selective small-molecule antagonist. 2015, Pubmed
Barro-Soria, Using fluorescence to understand β subunit-NaV channel interactions. 2017, Pubmed
Barro-Soria, KCNE1 divides the voltage sensor movement in KCNQ1/KCNE1 channels into two steps. 2014, Pubmed
Benatti, Polyunsaturated fatty acids: biochemical, nutritional and epigenetic properties. 2004, Pubmed
Bohannon, Polyunsaturated fatty acids produce a range of activators for heterogeneous IKs channel dysfunction. 2020, Pubmed , Xenbase
Bohnen, Molecular Pathophysiology of Congenital Long QT Syndrome. 2017, Pubmed
Bruno, Docosahexaenoic acid alters bilayer elastic properties. 2007, Pubmed
Buraei, Structure and function of the β subunit of voltage-gated Ca²⁺ channels. 2013, Pubmed
Börjesson, Lipoelectric modification of ion channel voltage gating by polyunsaturated fatty acids. 2008, Pubmed , Xenbase
Börjesson, An electrostatic potassium channel opener targeting the final voltage sensor transition. 2011, Pubmed , Xenbase
Calloe, Characterization and mechanisms of action of novel NaV1.5 channel mutations associated with Brugada syndrome. 2013, Pubmed
Capes, Domain IV voltage-sensor movement is both sufficient and rate limiting for fast inactivation in sodium channels. 2013, Pubmed , Xenbase
Chanda, Tracking voltage-dependent conformational changes in skeletal muscle sodium channel during activation. 2002, Pubmed , Xenbase
Chen, Structural basis of the alpha1-beta subunit interaction of voltage-gated Ca2+ channels. 2004, Pubmed
Chockalingam, Not all beta-blockers are equal in the management of long QT syndrome types 1 and 2: higher recurrence of events under metoprolol. 2012, Pubmed
Deal, Molecular physiology of cardiac potassium channels. 1996, Pubmed
Dick, Arrhythmogenesis in Timothy Syndrome is associated with defects in Ca(2+)-dependent inactivation. 2016, Pubmed
Endo, Cardioprotective mechanism of omega-3 polyunsaturated fatty acids. 2016, Pubmed
Fernández-Falgueras, Cardiac Channelopathies and Sudden Death: Recent Clinical and Genetic Advances. 2017, Pubmed
Fridericia, The duration of systole in an electrocardiogram in normal humans and in patients with heart disease. 1920. 2003, Pubmed
Harmer, Mechanisms of disease pathogenesis in long QT syndrome type 5. 2010, Pubmed
Hoffman, Voltage-gated ion channelopathies: inherited disorders caused by abnormal sodium, chloride, and calcium regulation in skeletal muscle. 1995, Pubmed
Hsu, Regulation of Na+ channel inactivation by the DIII and DIV voltage-sensing domains. 2017, Pubmed , Xenbase
Huang, Mechanisms of KCNQ1 channel dysfunction in long QT syndrome involving voltage sensor domain mutations. 2018, Pubmed
Hullin, Cardiac L-type calcium channel beta-subunits expressed in human heart have differential effects on single channel characteristics. 2003, Pubmed
Kang, Evidence that free polyunsaturated fatty acids modify Na+ channels by directly binding to the channel proteins. 1996, Pubmed
Kang, Prevention of fatal cardiac arrhythmias by polyunsaturated fatty acids. 2000, Pubmed
Larsson, KCNE1 tunes the sensitivity of KV7.1 to polyunsaturated fatty acids by moving turret residues close to the binding site. 2018, Pubmed , Xenbase
Lei, Two components of the delayed rectifier potassium current, IK, in rabbit sino-atrial node cells. 1996, Pubmed
Liin, Biaryl sulfonamide motifs up- or down-regulate ion channel activity by activating voltage sensors. 2018, Pubmed
Liin, Polyunsaturated fatty acid analogs act antiarrhythmically on the cardiac IKs channel. 2015, Pubmed , Xenbase
Liin, Fatty acid analogue N-arachidonoyl taurine restores function of IKs channels with diverse long QT mutations. 2016, Pubmed , Xenbase
Liin, Mechanisms Underlying the Dual Effect of Polyunsaturated Fatty Acid Analogs on Kv7.1. 2018, Pubmed , Xenbase
Ma, Characterization of a novel KCNQ1 mutation for type 1 long QT syndrome and assessment of the therapeutic potential of a novel IKs activator using patient-specific induced pluripotent stem cell-derived cardiomyocytes. 2015, Pubmed
Ma, High purity human-induced pluripotent stem cell-derived cardiomyocytes: electrophysiological properties of action potentials and ionic currents. 2011, Pubmed
Marx, Requirement of a macromolecular signaling complex for beta adrenergic receptor modulation of the KCNQ1-KCNE1 potassium channel. 2002, Pubmed
Murray, Unnatural amino acid photo-crosslinking of the IKs channel complex demonstrates a KCNE1:KCNQ1 stoichiometry of up to 4:4. 2016, Pubmed
Nakajo, Stoichiometry of the KCNQ1 - KCNE1 ion channel complex. 2010, Pubmed , Xenbase
Nerbonne, Molecular physiology of cardiac repolarization. 2005, Pubmed
Nguyen, Structural basis for antiarrhythmic drug interactions with the human cardiac sodium channel. 2019, Pubmed
Noble, Reconstruction of the repolarization process in cardiac Purkinje fibres based on voltage clamp measurements of membrane current. 1969, Pubmed
O'Hara, Simulation of the undiseased human cardiac ventricular action potential: model formulation and experimental validation. 2011, Pubmed
Osteen, KCNE1 alters the voltage sensor movements necessary to open the KCNQ1 channel gate. 2010, Pubmed , Xenbase
Pepe, Omega 3 polyunsaturated fatty acid modulates dihydropyridine effects on L-type Ca2+ channels, cytosolic Ca2+, and contraction in adult rat cardiac myocytes. 1994, Pubmed
Rivolta, A novel SCN5A mutation associated with long QT-3: altered inactivation kinetics and channel dysfunction. 2002, Pubmed
Ronaldson-Bouchard, Advanced maturation of human cardiac tissue grown from pluripotent stem cells. 2018, Pubmed
Rougier, Cardiac voltage-gated calcium channel macromolecular complexes. 2016, Pubmed
Sanguinetti, Dysfunction of delayed rectifier potassium channels in an inherited cardiac arrhythmia. 1999, Pubmed
Schwartz, Long-QT syndrome: from genetics to management. 2012, Pubmed
Scuderi, Naturally Engineered Maturation of Cardiomyocytes. 2017, Pubmed
Spencer, Calcium transients closely reflect prolonged action potentials in iPSC models of inherited cardiac arrhythmia. 2014, Pubmed
Stotz, Functional roles of cytoplasmic loops and pore lining transmembrane helices in the voltage-dependent inactivation of HVA calcium channels. 2004, Pubmed
Tang, Structural basis for inhibition of a voltage-gated Ca2+ channel by Ca2+ antagonist drugs. 2016, Pubmed
Tomek, Development, calibration, and validation of a novel human ventricular myocyte model in health, disease, and drug block. 2019, Pubmed
Verkerk, Patch-Clamp Recording from Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes: Improving Action Potential Characteristics through Dynamic Clamp. 2017, Pubmed
Waddell-Smith, Update on the Diagnosis and Management of Familial Long QT Syndrome. 2016, Pubmed
Xiao, Suppression of voltage-gated L-type Ca2+ currents by polyunsaturated fatty acids in adult and neonatal rat ventricular myocytes. 1997, Pubmed
Xiao, Single point mutations affect fatty acid block of human myocardial sodium channel alpha subunit Na+ channels. 2001, Pubmed
Xiao, Blocking effects of polyunsaturated fatty acids on Na+ channels of neonatal rat ventricular myocytes. 1995, Pubmed
Xiao, Coexpression with beta(1)-subunit modifies the kinetics and fatty acid block of hH1(alpha) Na(+) channels. 2000, Pubmed
Zhang, Molecular determinants of voltage-dependent inactivation in calcium channels. 1994, Pubmed , Xenbase
Zhu, Mechanisms of noncovalent β subunit regulation of NaV channel gating. 2017, Pubmed