Limiting 20S proteasome assembly leads to unbalanced nucleo-cytoplasmic distribution of 26S/30S proteasomes and chronic proteotoxicity.

In addition to the degradation of cell-cycle proteins, short-lived, damaged, or unfolded proteins are constantly cleared from cells by the proteasome. During proliferation, the proteasome localizes to the nucleus and cytoplasm; however, the functional relevance of this compartmentalization remains unclear. Here, we show that folding stress increases 26S/30S proteasome activity, which correlates with the upregulation of Ump1, a chaperone involved in 20S assembly.

Auto-sumoylation of the Ubc9 E2 SUMO-conjugating Enzyme Extends Cellular Lifespan.

Calorie restriction (CR) provides anti-aging benefits through diverse processes, such as reduced metabolism and growth and increased mitochondrial activity. Although controversy still exists regarding CR-mediated lifespan effects, many researchers are seeking interventions that mimic the effects of CR. Yeast has proven to be a useful model system for aging studies, including CR effects.

Yeast 26S proteasome nuclear import is coupled to nucleus-specific degradation of the karyopherin adaptor protein Sts1.

In eukaryotes, the ubiquitin-proteasome system is an essential pathway for protein degradation and cellular homeostasis. 26S proteasomes concentrate in the nucleus of budding yeast Saccharomyces cerevisiae due to the essential import adaptor protein Sts1 and the karyopherin-α protein Srp1. Here, we show that Sts1 facilitates proteasome nuclear import by recruiting proteasomes to the karyopherin-α/β heterodimer.

Sis2 regulates yeast replicative lifespan in a dose-dependent manner.

Application of microfluidic platforms facilitated high-precision measurements of yeast replicative lifespan (RLS); however, comparative quantification of lifespan across strain libraries has been missing. Here we microfluidically measure the RLS of 307 yeast strains, each deleted for a single gene. Despite previous reports of extended lifespan in these strains, we found that 56% of them did not actually live longer than the wild-type; while the remaining 44% showed extended lifespans, the degree of extension was often different from what was previously reported.

A Novel Robust Screening Assay Identifies Strains as Reliable Antagonists of the Root-Knot Nematode .

Forty-four bacterial strains isolated from greenhouse soil and beetroots were tested for their antagonistic activity against the plant-parasitic root-knot nematode (RKN) , which causes significant yield losses in a number of important crops worldwide. Through a novel combination of in vitro and on planta screening assays, spp. 105 and 108 were identified as the most promising bacterial isolates.