Implications of the Actin Cytoskeleton on the Multi-Step Process of [] Prion Formation.

Yeast prions are self-perpetuating misfolded proteins that are infectious. In yeast, [] is the prion form of the Sup35 protein. While the study of [] has revealed important cellular mechanisms that contribute to prion propagation, the underlying cellular factors that influence prion formation are not well understood.

The actin cytoskeletal network plays a role in yeast prion transmission and contributes to prion stability.

Chaperone networks are required for the shearing and generation of transmissible propagons from pre-existing prion aggregates. However, other cellular networks needed for maintaining yeast prions are largely uncharacterized. Here, we establish a novel role for actin networks in prion maintenance.

The three faces of Sup35.

Sup35p is an essential protein in yeast that functions in complex with Sup45p for efficient translation termination. Although some may argue that this function is the only important attribute of Sup35p, there are two additional known facets of Sup35p's biology that may provide equally important functions for yeast; both of which involve various strategies for coping with stress. Recently, the N-terminal and middle regions (NM) of Sup35p, which are not required for translation termination function, have been found to provide stress-sensing abilities and facilitate the phase separation of Sup35p into biomolecular condensates in response to transient stress.

Spatial sequestration and oligomer remodeling during de novo [PSI] formation.

Prions are misfolded, aggregated, infectious proteins found in a range of organisms from mammals to bacteria. In mammals, prion formation is difficult to study because misfolding and aggregation take place prior to symptom presentation. The study of the yeast prion [PSI], which is the misfolded infectious form of Sup35p, provides a tractable system to monitor prion formation in real time.