Interplay between autophagy and proteasome during protein turnover

ER-anchored protein sorting controls the fate of two proteasome activators for intracellular organelle communication during proteotoxic stress

“…The seven most intense precursor ions were sequentially fragmented in each scan cycle using higher energy collisional dissociation (HCD) fragmentation. In all measurements, sequenced precursor masses were excluded from further selection for 30 s. The target values were 10 5 charges for MS/MS fragmentation and 3 × 10 6 charges for the MS scan.…”

“…Next, 2 leaf disks per replicates were sampled and homogenized in 200µl 10mM MgCl 2 and a serial dilution from 10 -1 to 10 -6 in 200µL was done. For bacterial counting, 20µL of 10 -5 and 10 -6 dilutions were plated. Growing colony-forming units were counted and Log10CFU/cm² was calculated.…”

“…One of the major protein quality control machineries across the tree of life is the ubiquitin-proteasome system (UPS). The UPS controls proteostasis through selective elimination of defective proteins and short-lived regulatory proteins 5 . To rapidly react to proteotoxic stress, all the constituents of the 26S proteasome are under a tight transcriptional control.…”

“…One of the major protein quality control machineries across the tree of life is the ubiquitin-proteasome system (UPS). The ubiquitin-proteasome system controls proteostasis through selective elimination of defective proteins as well as short-lived regulatory proteins (Raffeiner et al, 2023). Selective protein degradation by the proteasome proceeds from the ligation of ubiquitin proteins to a lysine residue within specific target proteins via the concerted action of E1, E2, and E3 enzymes.…”

Impairment of proteasome-associated deubiquitinating enzyme Uchl5/UBH-4 affects autophagy

“…Due to their modes of action Usp14 and Uchl5 affect the kinetics and affinity of the substrate-proteasome interaction, thereby influencing the proteolytic capacity of the proteasome. Impaired Usp14 or Uchl5 function have been reported to enhance proteasomal degradation of substrates (Lam et al, 1997) (Hanna et al, 2006) (Koulich et al, 2008) (Matilainen et al, 2013) (H. T. Kim & Goldberg, 2017) (H. T. Kim & Goldberg, 2018) (J. H. Lee et al, 2018) (Deol et al, 2020), but also to cause accumulation of proteasomal substrates (J. H. Lee et al, 2018) (Chadchankar et al, 2019) In the past, autophagy and UPS were believed to function as independent systems targeting distinct substrates, however, accumulating evidence describes interactions between these two systems including some shared substrates [reviewed in (Pohl & Dikic, 2019) (Raffeiner et al, 2023)]. The interplay is not always a direct compensatory mechanism but exhibits complexity and diversity.…”