Condensed Matter Physics Seminar: Development of camera based fluorescence correlation spectroscopy for elucidation of membranal protein dynamics

Abstract:

Juxtacrine signaling is a contact dependent signaling pathway. For example, the Notch signaling pathway relies on contact interaction between the membrane-bound Notch receptors and its membrane-bound Delta ligands. This signaling pathway is responsible for coordinating cellular differentiation of neighboring cells during embryonic development. 

The rate of signaling between cells crucially depends on the complex dynamics of Notch and Delta on the cell's membrane.  The biophysical processes that govern these dynamics  include diffusion along the 2D membrane, endocytosis and exocytosis (recycling of delta into and out of the membrane). 

These parameters were previously measured in our lab for Delta-like-1 (Dll1) fused to a red fluorescent protein (mCherry) using fluorescence recovery after photobleaching (FRAP) combined with total internal reflection (TIRF) imaging. The results revealed complex dynamics with large cell to cell variability.   

To get a better understanding of the surface dynamics of Dll1, I combine camera-based fluorescence correlation spectroscopy (2D-FCS), TIRF, and a pH sensitive protein tagging. These methods would allow us to map the diffusion and endocytosis rates over the whole basal membrane, compare between different Dll1 variants, and determine whether there are multiple species (e.g. multimers) controlling Dll1 dynamics. 

Seminar Organizer: Dr. Eran Sela