Biology Colloquium - Dr. Karine Gousset

Biology Colloquium - Dr. Karine Gousset

Postby cdouglas » Wed Dec 05, 2012 4:05 pm

BIOLOGY COLLOQUIUM
VIROLOGY FACULTY CANDIDATE


Dr. Karine Gousset
Membrane Trafficking and Pathogenesis Unit
Institut Pasteur

“Intercellular Transfer of HIV-1 and Prions:
Two Efficient Mechanisms to Avoid Detection”

Friday, December 14, 2012
3:00-4:00 PM
Science 2, Room 109

Cell-to-cell communication is essential for multicellular organisms. The intercellular exchanges of signals or materials occur via secretion, synapses, specialized junctions or direct cell-to-cell contact. Pathogens, which require living cells to replicate and propagate, can usurp these mechanisms.

The viral HIV-1 Gag protein is both necessary and sufficient for virus particle assembly. Using a novel microscopy approach I have examined the localization and movement of Gag in primary human macrophages. Virus particles accumulated at the plasma membrane and in apparent internal compartments. Interestingly, virus particles in these compartments were rapidly recruited to the site of contact between infected macrophages and naïve T-cells. These data led to the discovery of virion channels connecting these compartments to the cell surface allowing for the efficient targeted trafficking of HIV-1 in macrophages.

Tunneling nanotubes (TNTs) are membrane bridges that allow the transport of various materials, including organelles, bacteria and viruses from one cell to another. I have shown that TNTs can form between non-infected and prion-infected neuronal cells, allowing for the trafficking of both endogenous and exogenous infectious prion particles (PrPSc) between cells. PrPSc trafficking was also observed between dendritic cells and neurons via TNTs, suggesting that TNTs could play an important role in the spreading of PrPSc from peripheral sites to the central nervous system.

While TNT-like structures have been identified in numerous cell types, they are heterogeneous and the molecular machinery involved in their formation and function remains elusive. Thus, to better characterize this type of long distance transport mechanism and to identify important molecular components in neuronal cells, I have now focused my studies on elucidating the role that the unconventional actin-based molecular motor Myosin-X plays in both TNT formation and transfer of membrane vesicles in general, and PrPSc in particular.

For further information: http://www.csufresno.edu/biology or phone 278-2001
cdouglas
 
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