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Liposomes, Exosomes, and Virosomes: From Modeling Complex
Membrane Processes to Medical Diagnostics and Drug Delivery
Thursday Speaker Abstracts
39
Stress-dependent Prion-like Aggregate Formation Regulates Protein Sorting and Export at
the Trans-Golgi Network
Claudia Stohrer, Martina Horanova,
Anne Spang
.
Organisms have to respond to environmental stress such as dehydration. To mount a rapid
response, sensors are present in the plasma membrane serving as a signal relay station.
Polycystin2 (PKD2)-related TRP channels act as mechanosensors and are activated under
hypotonic conditions. The yeast PKD2-related Flc2 is present at the plasma membrane and the
ER. The localization of the protein is dependent on the presence of functional ER-plasma
membrane contact sites and constant cycling between the trans-Golgi Network (TGN) and the
plasma membrane. Regulated export of Flc2 to the plasma membrane is achieved by the exomer
adaptor complex. While Flc2 is plasma membrane-localized in iso- and hypotonic medium, it is
rapidly endocytosed and stored in the TGN under hyperosmotic stress. Flc2 contains a short N-
rich unstructured stretch in the C-terminus, and TGN retention is at least partly dependent on the
prion-like domain of Pin2. This prion-like domain dependent retention mechanism prevents
untimely discharge of the proteins at the plasma membrane and equally protects it form
degradation. Upon stress removal, Flc2, similar to Pin2, quickly regained plasma membrane
localization, in a process involving the Batten disease protein Btn2, which has been implicated in
resolving prion aggregates. Thus Pin2 and Flc2 might be part of a stress-stabilized liquid droplet
domain at the TGN that is resolved by Btn2 when the stress subsides.
The Role of Cholesterol in Virus Entry
Lukas Tamm
University of Virginia, Charlottesville, VA, USA
No Abstract