PKCβII specifically regulates KCNQ1/KCNE1 channel membrane localization

The auxiliary subunit KCNE1 regulates KCNQ1 channel response to sustained calcium-dependent PKC activation

“…We also measured channel currents in cells expressing KCNQ1 and KCNE1 untagged subunits together with either CA-PKCβII or DN-PKCβII. Consistent with our previous data, currents were significantly decreased in CA-PKCβII expressing cells compared to DN-PKCβII for cells co-expressing KCNQ1 and KCNE1(WT) subunits [20,21] (Fig 3D). For cells expressing the KCNE1(S102A) subunit, channel function was not significantly different between CA-PKCβII and DN-PKCβII expressing cells (Fig 3D).…”

“…In the absence of KCNE1 expression, the channel remained in the membrane after cPKC stimulation ( Fig 1A). We have previously shown that channel internalization in response to GqPCR stimulation was prevented by cPKC and PKCbetaII inhibitors in cells expressing KCNQ1 and KCNE1 subunits [20,21]. In cells expressing only the KCNQ1-GFP subunit and α 1A adrenergic receptor, the channel remained in the membrane after treatment with the α 1A -AR agonist phenylephrine for 90 min (Phe, 30 μM, S1 Fig), consistent with the lack of effect of cPKC observed (Fig 1).…”

“…KCNQ1-GFP fluorescence was measured at both plasma membrane (M) and cytosolic (C) regions by subtracting the background in randomly selected rectangular regions for each individual cells (see Fig 1). Membrane localization was calculated as the ratio of membrane to cytoplasm fluorescence (M/C) [20,21,42]. The average membrane localization obtained in control conditions for each experimental day was used for normalization of each individual experiment [20].…”

“…To investigate the role of KCNE1(S102) on cPKC regulation of IKs channel membrane localization in the native system, KCNQ1-GFP was expressed with either wild-type KCNE1(WT) or KCNE1(S102A) in cardiomyocytes using adenoviral infection. We have previously shown that prolonged α1-AR activation inhibits channel membrane localization via cPKC activation, and inhibits KCNQ1/KCNE1 currents in cardiomyocytes [20,21], although the role of KCNE1 was not explored. Thus, we treated cardiac myocytes with the α1-AR agonist phenylephrine (Phe, 30 μM) for 90 min.…”

“…Acute cPKC activation has been shown to regulate cardiac channels, including IKs, in heterologous and native systems [13][14][15][16][17][18][19]. In addition, we have recently showed that prolonged cPKC stimulation, specifically the PKCβII isoform, leads to IKs channel internalization [20,21]. However, the role of the KCNE1 subunit on the PKCβIImediated inhibition of channel membrane localization was not explored.…”