Evidence for a protein tether involved in somatic touch.
The gating of ion channels by mechanical force underlies the sense of touch and pain. The mode of gating of mechanosensitive ion channels in vertebrate touch receptors is unknown. Here we show that the presence of a protein link is necessary for the gating of mechanosensitive currents in all low-threshold mechanoreceptors and some nociceptors of the dorsal root ganglia (DRG). Using TEM, we demonstrate that a protein filament with of length approximately 100 nm is synthesized by sensory neurons and may link mechanosensitive ion channels in sensory neurons to the extracellular matrix. Brief treatment of sensory neurons with non-specific and site-specific endopeptidases destroys the protein tether and abolishes mechanosensitive currents in sensory neurons without affecting electrical excitability. Protease-sensitive tethers are also required for touch-receptor function in vivo. Thus, unlike the majority of nociceptors, cutaneous mechanoreceptors require a distinct protein tether to transduce mechanical stimuli.
Hu
Jing
J
Department of Neuroscience, Max-Delbrück Center for Molecular Medicine and Charité Universitätsmedizin Berlin, Berlin-Buch, Germany. jing.hu@cin.uni-tuebingen.de
Chiang
Li-Yang
LY
Koch
Manuel
M
Lewin
Gary R
GR
D000818:Animals; D002478:Cells, Cultured; D018920:Coculture Techniques; D016326:Extracellular Matrix Proteins / Q000502:physiology / Q000648:ultrastructure; D005727:Ganglia, Spinal / Q000166:cytology / Q000502:physiology; D015640:Ion Channel Gating; D008465:Mechanoreceptors / Q000502:physiology; D040542:Mechanotransduction, Cellular / Q000502:physiology; D051379:Mice; D046529:Microscopy, Electron, Transmission; D008959:Models, Neurological; D041681:NIH 3T3 Cells; D009419:Nerve Tissue Proteins / Q000502:physiology* / Q000648:ultrastructure; D011984:Sensory Receptor Cells / Q000502:physiology*; D012867:Skin / Q000294:innervation; D014110:Touch / Q000502:physiology*
D016326:Extracellular Matrix Proteins; D009419:Nerve Tissue Proteins