Effects of TMEM43 on conduction velocity and sodium channel expression.

A. Electrograms recorded from adjacent MEA electrodes in HL-1 cell cultures. All cells beat spontaneously. Control and TMEM43-WT cells beat with a regular, synchronous rhythm. TMEM43-S358L cells beat with an irregular, comparatively slowed rhythm. B. Average velocity illustrating a decrease in conduction velocity of the TMEM43-S358L cells (1.2 cm/s) compared to control cells (2.5 cm/s) and TMEM43-WT cells (2.1 cm/s) (n = 7 control, n = 6 TMEM43-WT and n = 6 TMEM43-S358L, * pC. Western blot demonstrating expression of NaV1.5 in control, TMEM43-WT and TMEM43-S358L cells. GAPDH was used as a loading control. Rabbit polyclonal NaV1.5 antibody specifically detected sodium ion channel (NaV1.5) expression in all three cell types. Neither wild-type nor mutant TMEM43 altered the NaV1.5 expression. All results are representative of three independent Western blot experiments.