Ph.D. David P. Corey
Department of Neurobiology
Harvard Medical School
Boston, MA

Thursday, December 18, 2003
10:00 am (CT)
3169 Beckman Institute

Abstract

Hair cells in the auditory and vestibular systems convert auditory and balance stimuli into a neural code, by opening mechanically-gated ion channels in response to deflection of their ciliary bundles.  They also regulate tension on the channels by means of myosin motors located within tens of nanometers of the channels. The myosin-based regulation or adaptation occurs on a timescale of milliseconds. Experiments with animals expressing a mutant myosin demonstrate that this form of adaptation is mediated by myosin type 1c.  There is also a faster, Ca2+-based adaptation that occurs in a millisecond or less, which is mediated by Ca2+ binding within nanometers of the channel.  Measurements of bundle movements occurring upon Ca2+ entry show that Ca2+ binding shifts the force dependence of channel opening so that about 2.5 pN more force is needed to open a Ca2+-bound channel.

Tea and coffee will be served in R3151 Beckman Institute at 2:15pm.