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The T1‐tetramerisation domain of Kv1.2 rescues expression and preserves function of a truncated NaChBac sodium channel
Author(s) -
D’Avanzo Nazzareno,
Miles Andrew J.,
Powl Andrew M.,
Nichols Colin G.,
Wallace B.A.,
O’Reilly Andrias O.
Publication year - 2022
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1002/1873-3468.14279
Subject(s) - cytoplasm , chimera (genetics) , mutant , sodium channel , microbiology and biotechnology , biophysics , chemistry , ion channel , transmembrane domain , alternative splicing , biology , membrane , sodium , messenger rna , biochemistry , gene , receptor , organic chemistry
Cytoplasmic domains frequently promote functional assembly of multimeric ion channels. To investigate structural determinants of this process, we generated the ‘T1‐chimera’ construct of the NaChBac sodium channel by truncating its C‐terminal domain and splicing the T1‐tetramerisation domain of the Kv1.2 channel to the N terminus. Purified T1‐chimera channels were tetrameric, conducted Na + when reconstituted into proteoliposomes, and were functionally blocked by the drug mibefradil. Both the T1‐chimera and full‐length NaChBac had comparable expression levels in the membrane, whereas a NaChBac mutant lacking a cytoplasmic domain had greatly reduced membrane expression. Our findings support a model whereby bringing the transmembrane regions into close proximity enables their tetramerisation. This phenomenon is found with other channels, and thus, our findings substantiate this as a common assembly mechanism.