Saturday 3 June 2006
Specific myosins are implicated in sensory transduction.
Mutations in the genes encoding myosin-VI and myosin-VIIa have been linked to several disorders characterized by deafness in humans.
The strongest evidence of a defect in vesicular transport in this group of diseases is found in Usher syndrome type 1B, which is caused by mutations in the gene for myosin-VIIa.
In addition to deafness, patients with this syndrome have retinitis pigmentosa, which leads to blindness.
Myosin-VIIa is abundant in the synaptic regions of photoreceptor cells and presumably acts as an actin-based motor protein involved in the formation and transport of the ribbon-synaptic vesicle complexes characteristic of these sensory cells.
Furthermore, myosin-VIIa may be involved in the renewal of the outer photoreceptor disks, a process requiring efficient membrane transport, and in endocytic transport in cochlear hair cells.
vesicula transport (vesicle transport)
- cadherin-associated deafness