Tri-Institutional Faculty

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Timothy Ryan, Ph.D.

Tri-Institutional Professor
Weill Cornell Medical College
Department of Biochemistry

Dr. Ryan’s laboratory is interested in the molecular basis of synaptic function, the essential point of communication between neurons. Dr. Ryan and his colleagues focus on presynaptic biology, in which neurotransmitter-containing synaptic vesicles fuse with the plasma membrane at the synapse in response to electrical stimulation. To carry out this work, his lab develops and uses optical techniques to measure synaptic function in real time. Combined with molecular and chemical tools, this approach allows them to address fundamental questions about how synaptic communication is controlled. Areas of interest include the process of synaptic vesicle recycling, whereby, after a vesicle releases its neurotransmitter, the proteins that make up the vesicle must be recycled by endocytosis where materials on the surface of a cell are engulfed by the cell membrane and internalized. His lab recently developed biophysical approaches to follow this process one vesicle at a time. In doing so, they discovered that the speed of this process is determined by the identity of the neuron that a synapse belongs to. Recently the lab has also developed successful approaches for examining how release probability is controlled at the single-synapse level.

Through his studies on synapse function, Dr. Ryan hopes to gain insight into how information is controlled both in normal and diseased states of brain function.

  • Raimondi, A. et al. Overlapping role of dynamin isoforms in synaptic vesicle endocytosis. Neuron 70, 1100–1114 (2011).
  • Armbruster, M. and Ryan, T.A. Synaptic vesicle retrieval time is a cell-wide rather than individual-synapse property. Nat. Neurosci. 14, 824–826 (2011).
  • Kim, S.H. and Ryan, T.A. CDK5 servers as a major control point in neurotransmitter release. Neuron 67, 797–809 (2010).