Yeast Short-Lived Actin-Associated Protein Forms a Metastable Prion in Response to Thermal Stress.

Self-perpetuating ordered protein aggregates (amyloids and prions) are associated with a variety of neurodegenerative disorders. Although environmental agents have been linked to certain amyloid diseases, the molecular basis of their action remains unclear. We have employed endogenous yeast prions as a model system to study environmental control of amyloid formation. A short-lived actin-associated yeast protein Lsb2 can trigger prion formation by other proteins in a mode regulated by the cytoskeleton and ubiquitin-dependent processes. Here, we show that such a heterologous prion induction is due to the ability of Lsb2 to form a transient prion state, generated in response to thermal stress. Evolutionary acquisition of prion-inducing activity by Lsb2 is traced to a single amino acid change, coinciding with the acquisition of thermotolerance in the Saccharomyces yeast lineage. This raises the intriguing possibility that the transient prion formation could aid in functioning of Lsb2 at higher temperatures.

Tubal origin of ovarian endometriosis and clear cell and endometrioid carcinoma.

Current research has strongly proposed that contrary to prior beliefs, many ovarian epithelial cancers (OECs) do not, as their name suggests, originate in the ovaries. Recent findings regarding both high-grade and low-grade serous carcinomas has implicated the fallopian tube as a cell source for these OECs, but until now, there has been little insight into the cellular source for clear cell and endometrioid carcinomas. In this commentary review article, we aimed to discuss the new findings that support the possible contribution from the fallopian tube in clear cell and endometrioid carcinomas. Specifically, we have provided results that showcased ovarian surface epithelia (OSE) and ovarian epithelial inclusions (OEIs) as having mesothelial and tubal origins and have strongly recognized the secondary müllerian system and the ability for tubal epithelia to implant upon the ovarian surface as contributing to fallopian tube-derived OEIs (F-OEIs). We have provided initial indications of these F-OEIs and their relationship to endometriosis and then clear cell and endometrioid carcinomas and subsequently offer our new proposal of a probable tubal origin. This new proposal is a paradigm that drastically changes the understanding behind the origin of these OECs and has significant clinical implications in the near future.