The DEG/ENaC Protein MEC-10 Regulates the Transduction Channel Complex in Caenorhabditis Elegans Touch Receptor Neurons
Gentle touch sensation in Caenorhabditis elegans is mediated by the MEC-4/MEC-10 channel complex, which is expressed exclusively in six touch receptor neurons (TRNs). The complex contains two pore-forming subunits, MEC-4 and MEC-10, as well as the accessory subunits MEC-2, MEC-6, and UNC-24. MEC-4 is essential for channel function, but beyond its role as a pore-forming subunit, the functional contribution of MEC-10 to the channel complex and to touch sensation is unclear.Weaddressed this question using behavioral assays, in vivo electrophysiological recordings from TRNs, and heterologous expression of mutant MEC-10 isoforms. Animals with a deletion in mec-10 showed only a partial loss of touch sensitivity and a modest decrease in the size of the mechanoreceptor current (MRC). In contrast, five previously identified mec-10 alleles acted as recessive gain-of-function alleles that resulted in complete touch insensitivity. Each of these alleles produced a substantial decrease in MRC size and a shift in the reversal potential in vivo. The latter finding indicates that these mec-10 mutations alter the ionic selectivity of the transduction channel in vivo. All mec-10 mutant animals had properly localized channel complexes, indicating that the loss of MRCs was not attributable to a dramatic mislocalization of transduction channels. Finally, electrophysiological examination of heterologously expressed complexes suggests that mutant MEC-10 proteins may affect channel current via MEC-2.
10.1523/JNEUROSCI.4580-10.2011Final published version Open
MSU Digital Commons Citation
Árnadóttir, Jóhanna; O'Hagan, Robert; Chen, Yushu; Goodman, Miriam B.; and Chalfie, Martin, "The DEG/ENaC Protein MEC-10 Regulates the Transduction Channel Complex in Caenorhabditis Elegans Touch Receptor Neurons" (2011). Department of Biology Faculty Scholarship and Creative Works. 141.