UC San Diego, Department of Bioengineering

2:00 PM - Friday, December 4

Ellen Lumpkin, Ph.D.
Neuroscience, Molecular Physiology and Biophysics, Molecular and Human Genetics
Baylor College of Medicine

The goal of our research is to discover mechanotransduction molecules that initiate touch sensation in mammals. Much of our effort focuses on mammalian Merkel cell-neurite complexes, which are exquisitely sensitive touch receptors that encode object shape and fine textures. Merkel cells are enigmatic epidermal cells first described in 1875. The role that these cells play in touch reception has been the subject of controversy for 40 years. Based on morphology, Merkel cells are proposed to be mechanosensory cells that transduce force into membrane-potential changes, and then signal afferent neurons through synaptic transmission. To test this hypothesis, we use mouse genetics, in vitro systems and intact electrophysiological recordings. Our in vitro studies have demonstrated that Merkel cells are force-sensitive and that voltage-activated channels open downstream of mechanical stimuli. To determine whether Merkel cells are necessary for touch responses in the intact skin, we generated mice that selectively lack Merkel cells in the body skin. With intact electrophysiological recordings, we demonstrated a complete absence of one class of light-touch responses in these mice. Collectively, these results suggest that Merkel cells are required for appropriate sensory coding of light touch and pave the way to discover touch transduction mechanisms.