AMPK alters proteasome phosphorylation status and prevents persistent proteasome condensates.

Proteasomes are large multiprotein complexes required for selective intracellular protein degradation, regulating numerous cellular processes and maintaining protein homeostasis and organismal health. In the budding yeast Saccharomyces cerevisiae grown under different glucose conditions, proteasomes undergo dynamic phase transitions between free and condensate states concomitant with nucleocytoplasmic translocation. Low glucose-induced cytoplasmic proteasome condensates are usually reversible but become persistent in the absence of AMP-activated protein kinase (AMPK).

AMPK alters proteasome phosphorylation status and prevents persistent proteasome condensates.

Unlabelled: Proteasomes are large multiprotein complexes required for selective intracellular protein degradation, regulating numerous cellular processes and maintaining protein homeostasis and organismal health. In the budding yeast grown under different glucose conditions, proteasomes undergo dynamic phase transitions between free and condensate states concomitant with nucleocytoplasmic translocation. Low glucose-induced cytoplasmic proteasome condensates are usually reversible but become persistent in the absence of AMP-activated protein kinase (AMPK).

Pep12 is important for proteasome microautophagy under low glucose conditions.

Autophagic degradation of proteasomes is a highly conserved mechanism for regulating proteasome homeostasis in eukaryotes. Here we show that Pep12, a t-SNARE protein, is important for intralumenal vesicle formation in the vacuole and proteasome microautophagy under low glucose conditions. Deleting in yeast cells, , blocked proteasome fragmentation, by which the ESCRT-dependent microautophagy selectively degrades aberrant proteasomes.

Proteasome condensates repeatedly "contact and release" at the nuclear periphery during dissolution.

Stress-induced proteasome condensates have been identified in both yeast and mammalian cells. The biochemical properties and dynamics of proteasome condensates mainly depend on the specific stress conditions. In the budding yeast , cytoplasmic proteasome condensates assemble from the nuclear proteasomes under glucose starvation conditions.