The subfamily-specific assembly of Eag and Erg K+ channels is determined by both the amino and the carboxyl recognition domains

Ting Feng Lin, I. Wen Lin, Shu Ching Chen, Hao Han Wu, Chi Sheng Yang, Hsin Yu Fang, Mei Miao Chiu, Chung Jiuan Jeng*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


A functional voltage-gated K+ (Kv) channel comprises four pore-forming α-subunits, and only members of the same Kv channel subfamily may co-assemble to form heterotetramers. The ether-à-go-go family of Kv channels (KCNH) encompasses three distinct subfamilies: Eag (Kv10), Erg (Kv11), and Elk (Kv12). Members of different ether-à-go-go subfamilies, such as Eag and Erg, fail to form heterotetramers. Although a short stretch of amino acid sequences in the distal C-terminal section has been implicated in subfamily-specific subunit assembly, it remains unclear whether this region serves as the sole and/or principal subfamily recognition domain for Eag and Erg. Here we aim to ascertain the structural basis underlying the subfamily specificity of ether-à-go-go channels by generating various chimeric constructs between rat Eag1 and human Erg subunits. Biochemical and electrophysiological characterizations of the subunit interaction properties of a series of different chimeric and truncation constructs over the C terminus suggested that the putative C-terminal recognition domain is dispensable for subfamily-specific assembly. Further chimeric analyses over the Nterminus revealed that the N-terminal region may also harbor a subfamily recognition domain. Importantly, exchanging either the N-terminal or the C-terminal domain alone led to a virtual loss of the intersubfamily assembly boundary. By contrast, simultaneously swapping both recognition domains resulted in a reversal of subfamily specificity. Our observations are consistent with the notion that both the N-terminal and the C-terminal recognition domains are required to sustain the subfamily-specific assembly of rat Eag1 and human Erg.

Original languageEnglish
Pages (from-to)22815-22834
Number of pages20
JournalJournal of Biological Chemistry
Issue number33
StatePublished - 15 Aug 2014


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