SPEAKER: Dra. Cecilia Zaza (London Centre for Nanotechnology, University College London, UK)
TITLE: “Unravelling Protein Organization: Insights into T Cell Receptors and HIV-1 Env Using Single Molecule Localization microscopy”
DATE: Thursday, December 5, 12.00 PM.
VENUE: IBioBA´s seminar room. Godoy Cruz 2390, C1425FQD, Buenos Aires, Argentina.
Abstract
The dynamic processes of cellular signaling and viral fusion depend on the orchestrated assembly of molecular machines, with receptor clusters and viral fusion proteins serving as key players. Both processes involve the precise aggregation of specialized proteins to facilitate critical biological functions. In cellular signaling, receptors cluster together to amplify and propagate external signals, creating a robust and efficient communication network within the cell. Similarly, viral fusion machines, or fusogens, must congregate at the host cell membrane to overcome energetic barriers and achieve membrane fusion, allowing the viral genome to enter and hijack the host cell machinery.
In this talk, I will demonstrate how we use DNA-PAINT, a single-molecule localization microscopy technique with single protein resolution, to quantify the spatial distribution of T cell receptors on the membrane of T-cells, a type of white blood cell and a key component of the immune system. We also show that we can combine this technique with spinning disc confocal microscopy to study actin remodelling and receptor organization in big areas to increase experiments throughout and at deep penetration depths. We also characterize this system with DNA-origami samples and different biological reference standards such as nuclear pore complexes and microtubules.
I will also the nanoscale arrangement of HIV-1 envelope glycoprotein (Env) trimers, which are essential for the virus to enter host cells such as macrophages and CD4+ T cells. We visualize and measure Env clustering on the surface of both mature and immature HIV-1 virions using DNA-PAINT. These Env microclusters are important targets for immune responses and important facilitators of viral entry.
The talk will go over in detail how enhanced super-resolution microscopy can provide vital insights into the nanoscale architecture of proteins involved in immune function and viral disease.