Protein distribution of Kcnq1, Kcnh2, and Kcne3 potassium channel subunits during mouse embryonic development

Abstract

Voltage-dependent potassium channels consist of a pore-forming ␣-subunit, which is modulated by additional ␤-ancillary or regulatory subunits. Kcnq1 and Kcnh2 ␣-channel subunits play pivotal roles in the developing and adult heart. However, Kcnq1 and Kcnh2 have a much wider expression profile than strictly confined to the myocardium, similar to their putative regulatory Kcne1-5 ␤-subunits. At present, the distribution of distinct potassium channel subunits has been partially mapped in adult tissues, whereas almost no information is available during embryonic development. In this study, we report a detailed analysis of Kcnq1, Kcnh2, and Kcne3 protein expression during mouse embryogenesis. Our results demonstrate that Kcnq1 and Kcnh2 are widely distributed. Coexpression of both ␣-subunits is observed in a wide variety of organs, such as heart and the skeletal muscle, whereas others display unique Kcnq1 or Knch2 expression. Interestingly, Kcne3 expression is also widely observed in distinct tissue layers during embryogenesis, supporting the notion that an exquisite balance of ␣-and ␤-subunit expression is required for modulating potassium conductance in distinct organs and tissue layers.

Functional Implications of KCNE Subunit Expression for the Kv7.5 (KCNQ5) Channel

“…Similar inhibitory effects of KCNE3 have been also observed on Kv7.4 currents [31]. KCNE3 and Kv7.4 are coexpressed in the inner and outer hair cells of the inner ear, and a functional interaction may influence electrical excitability and cell survival [31,33]. In addition, KCNE3 also modulates Kv members from other families.…”

Deep resequencing of the voltage-gated potassium channel subunit KCNE3 gene in chronic tinnitus

“…Like KCNE1, KCNE3 is expressed in the mammalian inner ear [14] and brain [15,16]. Both proteins interact to regulate trafficking, surface expression, and activation of another potassium channel, KCNH3, in the cortex and in other parts of the central nervous system [17].…”

Functional Significance of K+ Channel β-Subunit KCNE3 in Auditory Neurons

“…Recently, K ϩ channel ␤-subunits KCNE have been found as a novel family of regulators of K ϩ channels. KCNE3 was previously reported to be expressed in the cardiovascular, digestive, respiratory, skeletal, and nervous systems (37). Of particular interest, KCNE3 expression was exclusively confined to the cochlear epithelial lining, starting at embryonic day 14.5 (37).…”