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The OUHSC Department of Physiology Presents The Professor Tushar K. Chowdhury Memorial Lectureship with guest speaker:
Martin Chalfie, Ph.D.
University Professor, Columbia University
2008 Nobel Laureate in Chemistry
“Touch Sensing in C. elegans: Transduction and Modulation”
Gentle touch is sensed in the nematode Caenorhabditis elegans by six touch receptor neurons (TRNs). Transduction requires a hetero-trimeric channel comprised of two DEG/ENaC proteins, MEC-4 and MEC-10, in a 2:1 ratio. Touch sensitivity is modulated by several different factors and on at least two different time scales. Long-term vibration (which acts through integrins and other focal adhesion molecules in the TRNs) increases sensitivity, whereas low oxygen, high salt, and entry into the dauer state (which affect neurohormonal regulation of the TRNs) reduce sensitivity. All these modifications take at least 2 hours to affect touch sensitivity and act through the transcription factor DAF-16 to change the amount of surface MEC-4. Repetitive stimuli acting in the short term (minutes) also affect the channel by inactivating it. These changes, which are integrated at several levels within the animal and in the TRNS, allow the animals to respond
differently to touch under various environmental conditions and to prioritize sensory signals.