The Centre for BioSystems Science and Engineering (BSSE) cordially invites you to attend a special seminar:

Speaker: Prof. Yamuna Krishnan

Department of Chemistry,

Institute for Biophysical Dynamics,

Grossman Institute for Neuroscience

University of Chicago

Title: Intracellular electrophysiology

Abstract: 

I have been interested in exploring how the ionic milieu within an organelle facilitates organelle function. To map these lumenal chemistries, my lab developed a DNA-based, fluorescent reporter technology to quantitatively map ions such as H+, Cl- and Ca2+ within organelles (1). It can be applied to organelles of cells in culture, in live organisms (2) and in human patient cells (3,4). Our most recent reporter for absolute membrane potential ended a previous misconception by showing that many organelles do in fact, have membrane potential (4). Today I will discuss two new reporters for organellar Na+ and K+ : the final pieces needed to build an electrochemical model for organelle membranes (5,6). The only existing electrochemical model of a biological membrane is that of the cell membrane, first developed by Hodgkin and Huxley in 1952 for neurons (7). To accomplish this for organelles we will need input from physicists, cell biologists and electrophysiologists.

References:

1. Krishnan, Y. et. al. “Quantitative imaging of biochemistry in situ and at the nanoscale.” ACS Cent. Sci., 2020, 6, 1938–1954.
2. Narayanaswamy, N. et. al. “A pH-correctable, DNA-based fluorescent reporter for organellar Calcium.” Nature Methods, 2019, 16, 95-102.
3. Leung, K., et. al. “A DNA Nanomachine chemically resolves lysosomes in live cells.” Nature Nanotechnology, 2019, 14, 176-183.
4. Saminathan, A., et. al. “A DNA-based voltmeter for organelles.” Nature Nanotechnology, 2021, 16, 96-103.
5. Anees, P. et al. “DNA nanodevices for measuring the organelle-specific activity of potassium channels.” 2023, in revision.
6. Zou, J. et al. “A DNA nanodevice maps sodium at single organelle resolution” 2023, in revision.
7. Hodgkin A.L., Huxley A.F. “A quantitative description of membrane current and its application to conduction and excitation in nerve”. J. Physiol. 1952, 117, 500–44.