Biophysics of molecule-to-molecule and cell-to-cell communications
  • Jong-Bong Lee Ph.D
  • SLS Colloquia / Nov 15th 04:00 pm / BLDG 110 ROOM N104
Abstract

The temporal and mechanistic order of molecular interactions is essential to insure downstream communications in various biological events over long distances. DNA mismatch repair (MMR) catalyzes strand-specific DNA degradation and resynthesis by dynamic molecular coordination of sequential downstream pathways to correct DNA base-pairing errors that occur during DNA replication. By in vitro reconstitution of E. coli DNA mismatch repair on mismatched DNA at the single-molecule level, we found that the stochastic orchestration through thermal fluctuation-driven motion of MMR components controls MMR beginning with mismatch recognition through strand-specific excision. I will also present our biophysical studies of long-distance communication between cells. A novel cellular bridge connecting cells, termed “intercellular nanotube (INT)”, has been recognized as a new pathway for the distant transport of cytoplasmic components, virus, and pathogenic substances between donor and acceptor cells. However, it is not yet known how such a fine structure can extend over several hundred micrometers and sustain robust for several hours in culture. We visualized the process of INT formation in HeLa cells and identified the structure of INTs and their configuration in an intermediate state using real-time fluorescence microscopy and super-resolution fluorescence microscopy. These imaging studies reveal the mechanism of INT formation and suggest an intercellular nanostructure that may play a critical role in the formation of long-standing INTs between cells.