Touch sense is enhanced by deafness gene

Voltage-gated K+ channel protein

 KCNQ4

We recently discussed the role of ion channels in membrane potentials of excitable cells in my A&P class.  I don't think my students believe me when I say that ion channels are a "hot area" of neuroscience research and that understanding them better will lead to all kinds of new insights about how our nervous system works.

Well, today in Nature Neuroscience researchers reveal that a gene for a protein in voltage-gated potassium channels in sensory cells that is mutated in a form of progressive deafness is also responsible for helping us sense vibration in the skin.  When the gene is mutated, it limits hearing.  But the mutation heightens touch sensitivity in the skin. 

So folks with this form of deafness lose hearing but gain touch sensitivity. 

However, there doesn't seem to be any measurable advantage to the increased touch sensitivity.  Probably, there is a disadvantage.

The important thing here, I think, is that it shows us something about how this particular potassium ion channel, which inhibits neuron excitability, can be used to adjust the sensitivity of sensory neurons for touch.

Studies such as this help us understand that certain genes can be expressed in different cells and have similar functions--but different roles to play.  It also underscores the tendency of the human body to make more than one use of a particular process. 

If our A&P students start looking for the same mechanisms that appear in different parts of the body, then they'll gain a deeper understanding of human structure and function.

Want to know more?

Deafness Gene Heightens Touch
Tia Ghose
TheScientist November 20, 2011 
my-ap.us/s5OP8n
[Brief news article summarizing the discovery]

KCNQ4 K+ channels tune mechanoreceptors for normal touch sensation in mouse and man
M. Heidenreich, et. al.
Nature Neuroscience  20 November , 2011
doi:10.1038/nn.298 
my-ap.us/sNhC08
[Original research article]