Proteome stability and dynamic protein complex profiling identified EEF1A1 as a novel translation regulator of autophagy and mitophagy

Ribosomal proteins are major substrates of starvation-induced endosomal microautophagy in Drosophila

p62/SQSTM1: From an autophagy receptor to a condensate organizer of selective autophagy and stress signaling.

Upon exposure to stress, cells activate a variety of stress-response and quality-control mechanisms to maintain homeostasis. Dysregulation of these processes is implicated in numerous diseases, including cancer, liver disorders, and neurodegenerative diseases. p62/Sequestosome 1 (SQSTM1) is a multifunctional protein that plays a central role in protein homeostasis and stress responses by regulating autophagy and signal transduction pathways. Through its multiple protein-interacting domains, p62 functions both as a scaffold for selective autophagic degradation and as a signaling hub. Since our previous review of p62 a decade ago, substantial progress has been made in elucidating its molecular functions and physiological roles. Notably, p62 undergoes liquid-liquid phase separation with ubiquitinated proteins to form membraneless condensates, termed p62 bodies, when cells are exposed to proteotoxic stress. By sequestering specific proteins, p62 bodies act as platforms for autophagy-dependent degradation and stress signaling. These findings have substantially revised our view of p62 function, which was previously considered primarily as a receptor simply linking ubiquitinated substrates to autophagic membranes and connecting signaling molecules. This conceptual shift from one-to-one molecular interactions to multivalent, multimolecular, higher-order assemblies has fundamentally redefined the functional landscape of p62. In this review, we highlight how p62 bodies integrate selective autophagy and stress signaling, with a particular emphasis on their emerging roles in disease pathogenesis and their potential as therapeutic targets.

The glycolytic enzyme PGAM1 functions as a metabolic–autophagy checkpoint to coordinate growth and stress tolerance

Ribosome-associated chaperones integrate co-translational mitochondrial protein import, stress signaling and proteostasis in Saccharomyces cerevisiae.

Mitochondrial biogenesis requires the coordinated synthesis, targeting, and import of nuclear-encoded mitochondrial precursor proteins. Although ribosome-associated chaperones support co-translational protein folding, their genetic contributions to mitochondrial protein import and cellular homeostasis remain incompletely defined. Here, we investigate the roles of the nascent polypeptide-associated complex (NAC) and the ribosome-associated Hsp70 system Ssb1/2 in Saccharomyces cerevisiae. We show that NAC and Ssb1/2 have distinct yet partially overlapping functions in the handling of mitochondrial precursor proteins. Loss of NAC activates the mitochondrial retrograde pathway and enhances growth on ethanol as a non-fermentable carbon source without compromising respiratory competence, indicating metabolic adaptation rather than overt mitochondrial dysfunction. In contrast, Ssb1/2 deficiency disrupts cytosolic proteostasis, sensitizes cells to TORC1 inhibition, and impairs autophagy and mitophagy. Using a TEV protease-based import reporter, we show that Ssb1/2 promotes efficient co-translational distribution of precursor proteins, whereas NAC limits the accumulation of misfolded proteins at the mitochondrial surface. Biochemical analyses further reveal that Ssb1/2 supports the association of translating cytosolic ribosomes with the mitochondrial outer membrane, while NAC loss partially restores this interaction in the absence of Ssb1/2. Together, these findings establish NAC and Ssb1/2 as key components of an integrated network linking co-translational targeting, mitochondrial signaling, and cellular homeostasis.

ER-localized translational control as a nexus for proteostasis.

Maintenance of proteostasis is essential for cellular and organismal homeostasis, and disruption of protein quality control (QC) networks underlies numerous human diseases. The endoplasmic reticulum (ER) functions as a central organelle for the synthesis, folding, maturation, and trafficking of secretory and membrane proteins, and serves as a central hub of intracellular proteostasis. Recent studies have established that the ER membrane serves not only as a site of protein translocation but also as a dynamic platform integrating translational regulation, RNA surveillance, and multiple QC pathways. During ER-associated translation, cells continuously monitor ribosome dynamics, mRNA integrity, nascent-chain folding, and transmembrane protein insertion processes to prevent the accumulation of aberrant proteins. These surveillance systems include the PKR-like ER kinase (PERK)-mediated integrated stress response (ISR), regulated IRE1-dependent decay (RIDD), nonsense-mediated mRNA decay (NMD), RNA silencing, ribosome-associated QC (RQC), ubiquitin-fold modifier 1 conjugation (UFMylation), ER-phagy, and ER stress-induced pre-emptive QC (ERpQC). Although these pathways were originally characterized independently, increasing evidence indicates that they function cooperatively on or near the ER membrane to coordinate translational attenuation, mRNA degradation, ribosome recycling, nascent-chain elimination, and organelle remodeling. In particular, UFMylation has emerged as a central mechanism linking ER-associated RQC, translocation-associated QC (TAQC), and ER-phagy. Dysfunction of these ER-localized translational QC pathways contributes to neurodegeneration, inflammation, fibrosis, cancer, and aging-related disorders. In this review, we summarize recent advances in ER-localized translational control and discuss how integrated QC networks on the ER membrane maintain proteostasis and influence disease pathogenesis.

The Long Splice Variant of Ribosomal Protein S24 Protects Cells from Stress and Is Induced by AMPK-ULK1-Regulated Autophagy Independent of mTORC1

This study shows that an allosteric activator of AMPK is sufficient to induce RPS24L and autophagy in normoxia in an ULK1-dependent, but mTORC1-independent manner and interacts with RPS24 mRNA and its autophagy-dependent decrease shifts splicing toward the RPS24L variant.