TY - JOUR
T1 - The DEG/ENaC protein MEC-10 regulates the transduction channel complex in Caenorhabditis elegans touch receptor neurons
AU - Árnadóttir, Jóhanna
AU - O'Hagan, Robert
AU - Chen, Yushu
AU - Goodman, Miriam B.
AU - Chalfie, Martin
PY - 2011/8/31
Y1 - 2011/8/31
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=80052360310&partnerID=8YFLogxK
U2 - 10.1523/JNEUROSCI.4580-10.2011
DO - 10.1523/JNEUROSCI.4580-10.2011
M3 - Article
C2 - 21880930
AN - SCOPUS:80052360310
SN - 0270-6474
VL - 31
SP - 12695
EP - 12704
JO - Journal of Neuroscience
JF - Journal of Neuroscience
IS - 35
ER -