The MEC-4 DEG/ENaC channel of Caenorhabditis elegans touch receptor neurons transduces mechanical signals

Touch sensitivity in Caenorhabditis elegans

“…These data are consistent with the fact that in vivo, mec-4 (d) produces strong degeneration independent of mec-10, while mec-10(d) degeneration is less frequent and requires mec-4, and suggest that MEC-4 and MEC-10 have functional differences [38]. Finally, in vivo electrophysiology recordings of touch receptor neurons demonstrate that MEC-4 and MEC-10 transduce gentle touch stimuli ( [57], see below).…”

“…2) [44]. The second transmembrane domain (TMII) and the sequence preceding it are thought to contribute to the pore of the channel; mutations in these regions cause constitutive channel activity, blockage of the constitutive activity, or changes in ion selectivity [36,37,57]. The mutations that cause constitutive channel activity were first identified as changes in MEC-4, MEC-10, and other C. elegans degenerins that cause neurodegeneration [16,21,38].…”

“…Using techniques developed for patch-clamp recording from C. elegans neurons [32,52], PLM neurons were recorded from while mechanical stimuli were applied to the posterior body wall [57]. The onset of stimuli produced a mechanoreceptor current (MRC) that peaked rapidly and then decayed during continued force; removal of force produced an additional MRC of equal amplitude (Fig.…”

Worms under Pressure: Bulk Mechanical Properties of C. elegans Are Independent of the Cuticle

“…Mechanical forces are known to play a direct role in triggering signal transduction pathways in C. elegans (16,17). Because the adult worm has only 22 specialized nerve cells for mechanotransduction, the bulk mechanical properties of the organism will determine how mechanical stimuli are distributed across these A B specialized cells-mechanical coupling thus allows short timescale coupling of different mechanosensory neurons (52).…”

“…The importance of C. elegans mechanics is highlighted by previous studies suggesting that the worm's locomotory patterns and foraging behaviors are strongly dependent on mechanical and osmotic stresses (13)(14)(15). Indeed, external mechanical forces lead to the activation of known mechanosensory signal transduction pathways (16,17). Moreover, C. elegans is known to occupy diverse habitats-ranging from decaying compost to freshwater lake beds-in which it encounters a wide variety of mechanical loads (18).…”