Fig. 8.

Schematic models of possible TMC1 and TMC2 functions. a TMC1 and TMC2 may function as pore-forming subunits of the mechanotransduction channel, either in homomeric assemblies of TMC1 or TMC2 subunits or in heteromeric assemblies with other TMCs or other pore-forming subunits. b TMC1 and TMC2 may function as essential linker proteins that convey tension from the tip link to the transduction channel. In this scenario, TMC1 and TMC2 are not pore-forming subunits but are part of the transduction complex, close enough to affect permeation properties, perhaps stabilizing pore-forming subunits. c TMC1 and TMC2 may serve to anchor transduction channels to the cytoskeleton. In this scenario, loss of TMC1 and TMC2 would render the channel insensitive to tension applied perpendicular to the membrane. As with scenario b, TMC1 and TMC2 must be close enough to the channel to affect permeation properties in this model. Other models are also possible.