Molecular determinants for assembly of G-protein-activated inwardly rectifying K+ channels

Woodward, Robert, Stevens, Edward B and Murrell-Lagnado, Ruth D (1997) Molecular determinants for assembly of G-protein-activated inwardly rectifying K+ channels. Journal of Biological Chemistry, 272. pp. 10823-10830. ISSN 0021-9258

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Abstract

Kir3.1 and Kir3.2 associate to form G-protein-activated, inwardly rectifying K+ channels. To identify regions involved in the coassembly of these subunits, truncated Kir3.1 polypeptides were coexpressed with epitope-tagged subunits in an in vitro translation system. N-terminal, C-terminal, and core region polypeptides were coimmunoprecipitated with both Kir3.2 and Kir3.1, suggesting that multiple elements distributed throughout the Kir3.1 polypeptide contribute to intersubunit binding interactions. The Kir3.2 C-terminal polypeptide coimmunoprecipitated with the Kir3.1 C-terminal polypeptide, but neither region recognized the N-terminal domain and core region of the Kir3.1 subunit. This suggests that within Kir3 channels the C-terminal domains of neighboring subunits interact. Coexpression of the truncated polypeptides with Kir3.1 and Kir3.2 in Xenopus oocytes reduced functional expression of the heteromeric channels. Constructs encoding the core region plus N-terminal and proximal C-terminal regions competed more effectively than the core region alone, which supports the contribution of all three regions to intersubunit binding interactions. Proximal and distal segments of the C-terminal domain were as effective at inhibiting functional expression as the entire C-terminal domain.

Item Type: Article
Schools and Departments: School of Life Sciences > Biochemistry
Subjects: Q Science > QH Natural history > QH0301 Biology
Depositing User: Tom Gittoes
Date Deposited: 25 Mar 2015 10:49
Last Modified: 25 Mar 2015 10:49
URI: http://sro.sussex.ac.uk/id/eprint/52628
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