Office: ISA 6216
Lab: ISA 6063
Ph.D. physics, 1992 City University of New York
- Imaging Neuronal Activity
- Modeling Neuronal Information Processing
- Protein Interactions, Aggregation and Phase Separation
- Colloidal Models of Protein Interactions
Short-Term Plastic Changes in Neurons: One fundamental property of neurons is their "plasticity", i.e. their ability to alter their response after repeated stimulation. This ability is thought to underlie such essential processes as learning and memory formation. We are using high-speed optical recording techniques to monitor stimulation-induced changes in the spatial and temporal patterns of electrical activity and calcium elevation in the axons innervating the posterior pituitary gland. Using these optical data and simplified computational models, we are trying to unravel how the regulation of excitable responses and of calcium dynamics contributes to the well-known dependence of hormone release from the posterior pituitary gland on stimulation pattern. More general, we hope to gain insights into the dynamic behavior of groups of nerve cells and axons and how such dynamics contribute to neuronal plasticity.
Protein Interactions and Phase Separation: Proteins interact with each other either via non-specific physical interactions (Coulomb, van-der-Waals, hydrophobic) or via highly specific interactions critical for their biological function. While most attention is focused on specific interactions due to their importance to biological protein function, non-specific physical interactions can play important roles, as well. Our lab is particularly interested how non-specific interactions drive protein phase separation phenomena, including protein crystal growth, protein precipitation, liquid-liquid phase separation and even amyloid fibril formation. We are using spectroscopic techniques, light scattering, light microscopy and atomic force microscopy to study protein phase separation phenomena and their relation to protein interactions.
Transient Aggregates formed by Amyloid Proteins.
Atomic force microscope (AFM) images of small oligomers (two closely apposed structures in
front) and protofibrils (string of connected oligomers in the back) formed during the early stages
of amyloid fibril growth by hen egg white lysozyme. Amyloid proteins are related to many
devastating diseases, including Alzheimer's disease, Parkinson's disease and even type-2
diabetes. The AFM image is 125 nm on a side and the aggregates are 4 billionth of a meter (4nm)