In vivo imaging of C. elegans mechanosensory neurons demonstrates a specific role for the MEC-4 channel in the process of gentle touch sensation.
In the nematode C. elegans, genes encoding components of a putative mechanotransducing channel complex have been identified in screens for light-touch-insensitive mutants. A long-standing question, however, is whether identified MEC proteins act directly in touch transduction or contribute indirectly by maintaining basic mechanoreceptor neuron physiology. In this study, we used the genetically encoded calcium indicator cameleon to record cellular responses of mechanosensory neurons to touch stimuli in intact, behaving nematodes. We defined a gentle touch sensory modality that adapts with a time course of approximately 500 ms and primarily senses motion rather than pressure. The DEG/ENaC channel subunit MEC-4 and channel-associated stomatin MEC-2 are specifically required for neural responses to gentle mechanical stimulation, but do not affect the basic physiology of touch neurons or their in vivo responses to harsh mechanical stimulation. These results distinguish a specific role for the MEC channel proteins in the process of gentle touch mechanosensation.
Suzuki
Hiroshi
H
Division of Biology, University of California, San Diego, La Jolla, CA 92093, USA.
Kerr
Rex
R
Bianchi
Laura
L
Frøkjaer-Jensen
Christian
C
Slone
Dan
D
Xue
Jian
J
Gerstbrein
Beate
B
Driscoll
Monica
M
Schafer
William R
WR
D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000502:physiology*; D020746:Calcium Channels, L-Type / Q000502:physiology; D002478:Cells, Cultured; D008465:Mechanoreceptors / Q000502:physiology*; D040542:Mechanotransduction, Cellular / Q000235:genetics / Q000502:physiology*; D008564:Membrane Potentials / Q000502:physiology; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D014110:Touch / Q000235:genetics / Q000502:physiology*
D029742:Caenorhabditis elegans Proteins; D020746:Calcium Channels, L-Type; C115871:Mec-4 protein, C elegans; D008565:Membrane Proteins