Autophagy最新文献

The targeted degradation of oncogenic or misfolded proteins has emerged as a promising therapeutic strategy. While proteolysis-targeting chimeras (PROTACs) and related technologies have successfully hijacked the ubiquitin-proteasome system to eliminate disease-driving proteins, recent advances highlight the lysosome as a powerful alternative degradation route. Lysosome-based degradation strategies offer broader substrate scope, subcellular targeting flexibility, and the ability to degrade proteins beyond the reach of the proteasome. In this review, we provide a comprehensive overview of synthetic molecules and engineered systems designed to traffic target proteins to the lysosome. These include lysosome targeting chimeras (LYTACs), autophagy-targeting chimeras (AUTACs), autophagy-tethering compounds (ATTECs), and other modalities that exploit endogenous trafficking pathways for selective protein clearance. By mapping the current landscape of lysosome-targeting degraders, this article underscores the therapeutic potential of lysosomal proteolysis and outlines future directions for molecular engineering in this rapidly evolving field.

Despite the clinical success of PDCD1/PD-1 and CD274/PD-L1 immune checkpoint blockade in multiple cancers, its efficacy in colorectal cancer (CRC) remains limited. Here, we report that the combination of the tyrosine kinase inhibitor regorafenib with PDCD1 blockade enhances anti-tumor immunity in CRC, both in clinical observations and preclinical models. Mechanistically, regorafenib acts as a molecular glue, directly promoting the interaction between CD274 and the selective autophagy receptor SQSTM1/p62, leading to SQSTM1-mediated autophagic degradation of CD274 and restoration of T cell-mediated cytotoxicity. In summary, these findings identify a previously unrecognized role of regorafenib in modulating tumor immune evasion and provide a mechanistic rationale for its combination with PDCD1 inhibitors in CRC treatment.

PINK1-dependent activation of PRKN/parkin on depolarized mitochondria causes mitophagy. The deficiency of NME3, a nucleoside diphosphate kinase/NDPK on the outer mitochondria membrane (OMM), is associated with a fatal neurodegenerative disorder. Here, we report that NME3 deficiency impairs p-S65-ubiquitin (Ub)-dependent PRKN binding on depolarized mitochondria without involving the loss of Ub phosphorylation by PINK1. Our mechanistic investigation revealed that NME3 interacts with PLD6/MitoPLD to generate phosphatidic acid (PA) from cardiolipin on the OMM of damaged mitochondria after depolarization. This lipid signal is essential for positioning MFN2 nearby PINK1 for phosphorylation of Ub conjugates on MFN2, thus enabling the subsequent amplification of PRKN binding to mitochondria. We provide further evidence that mitochondria-endoplasmic reticulum (Mito-ER) tethering prohibits the proximity of MFN2 with PINK1 and PRKN amplification on mitochondria. Importantly, the loss of NME3-regulated PA signal causes Mito-ER tethering. Overall, our findings suggest that NME3 cooperates with PLD6 to generate PA as a critical step in Mito-ER untethering, allowing MFN2 access to PINK1 for p-S65-poly-Ub-dependent feedforward activation of PRKN.Abbreviation ACTB: actin beta; BDNF brain derived neurotrophic factor; CL: cardiolipin; CRISPR: clustered regularly interspaced short palindromic repeats; DAG: diacylglycerol; ER: endoplasmic reticulum; FCCP: carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone; FRET: Förster resonance energy transfer; IF: immunofluorescence; KO: knockout; KD: knockdown; LPIN1: lipin 1; MERCS: mitochondria-endoplasmic reticulum contact sites; MFN2: mitofusin 2; Mito: mitochondria; OMM: outer mitochondrial membrane; p-Ub: phosphorylated ubiquitin; PA: phosphatidic acid; PD: Parkinson disease; PINK1: PTEN induced kinase 1; PLA: proximity ligation assay; PLD6/MitoPLD: phospholipase D family member 6; PRKN: parkin RBR E3 ubiquitin protein ligase; RA: retinoic acid; RT-qPCR: reverse transcription-quantitative polymerase chain reaction; TEM: transmission electron microscopy; TN-NME3: TOMM20-NΔ-NME3; TOMM20: translocase of outer mitochondrial membrane 20; TUBB: tubulin beta class I; Ub: ubiquitin; VDAC: voltage dependent anion channel; WB: western blot.

The lysosome is not only a degradative organelle but also an essential platform for signal transduction, such as with MTOR signaling. The reciprocal regulation between the lysosome and MTOR is central to macroautophagy/autophagy and metabolism. MTOR-mediated suppression of lysosomal acidification is important for lysosomal activity, autophagic flux, and cell survival. VASN is a transmembrane glycoprotein whose function is not fully understood. In the present study, we report that VASN is a TGFB-inducible protein and plays a crucial role in positively regulating lysosomal acidification. As a potential mechanism, we demonstrated that VASN localizes to the lysosome, interacts with lysosomal MTOR and STK11IP, and disrupts the binding of STK11IP to MTOR and the V-ATPase, which was recently reported to suppress lysosomal acidification. We found that VASN's function in modulating lysosomal activity is essential for optimal mitophagy induced by TGFB and terminal erythroid differentiation and is critical for the progression of mutant KRAS-driven lung cancer. Overall, our study identified VASN as a novel TGFB-inducible regulator of lysosomal function.

Viral subversion of macroautophagy/autophagy is a well-established immune evasion strategy, with BCL2 homologs from γ-herpesviruses serving as prototypical inhibitors through BECN1 (beclin 1) sequestration. Yet the full spectrum of their functions remains incompletely understood. In our recent study, we uncovered a non-canonical role for the Kaposi's sarcoma-associated herpesvirus (KSHV)-encoded BCL2 homolog (vBCL2) during late lytic replication. Unexpectedly, vBCL2 hijacks the host NDP kinase NME2/NM23-H2 to activate the mitochondrial fission GTPase DNM1L/DRP1, promoting mitochondrial fragmentation. This organelle remodeling dismantles MAVS-mediated antiviral signaling and facilitates virion assembly. A vBCL2 mutant unable to bind NME2 fails to induce fission or complete the viral lifecycle. These findings provide a long-sought answer to why vBCL2 is indispensable during lytic infection, and uncover a new immune evasion strategy centered on mitochondrial control. Our work expands the current view of virus-organelle interactions beyond canonical autophagy control and offers new targets for therapeutic intervention.

In metazoans, autophagosomes fuse with late endosomes (LEs)/multivesicular bodies (MVBs) to form a hybrid organelle known as an amphisome. Subsequently upon fusion with lysosomes the contents of amphisomes are degraded. While the formation of metazoan amphisomes has been well established, it has remained an open question whether amphisomes form and deliver their cargo to the central vacuole for degradation in plant cells. In this mini review, we provide an update on recent discoveries in the field of plant autophagy that demonstrate the formation of amphisome-like organelles that are generated through several distinct autophagosome/MVB fusion pathways.Abbreviations: CFS1: FYVE domain-containing protein; CORVET: core vacuole/endosome tethering; ER: endoplasmic reticulum; ESCRT: endosomal sorting complex required for transport; FYVE: Fab1p, YOTB, Vac1p, and EEA1; FREE1: FYVE domain protein required for endosomal sorting; HOPS: homotypic fusion and protein sorting; LEs: late endosomes; MVBs: multivesicular bodies; PtdIns3P: phosphatidylinositol-3-phosphate; SNAREs: soluble NSF attachment protein receptors; VAPVs: VPS41-associated phagic vacuoles.

In macroautophagy/autophagy, the inner membrane of the autophagosome and its contents are degraded within the autolysosome, while outer membrane proteins are recycled via a process known as autophagosomal components recycling (ACR). ACR is mediated by the recycler complex, powered by dynein-dynactin complexes, and regulated by RAB32-family small GTPases. However, it remains unknown whether ACR is subject to nutrient signal regulation or whether additional molecular components participate in the recycler complex. Our latest research identifies SNX16 as a new component of the recycler complex and reveals that MTORC1 phosphorylates SNX16, enabling SNX16 to function as a nutrient sensor that regulates ACR.

Macroautophagy/autophagy exerts multilayered protective functions in intestinal epithelial cells (IECs) while a loss-of-function genetic variant in ATG16L1 (autophagy related 16 like 1) is associated with risk for developing Crohn disease (CD). Westernization of diet, partly characterized by excess of long-chain fatty acids, contributes to CD, and a metabolic control of intestinal inflammation is emerging. Here, we report an unexpected inflammatory function for ATG16L1-mediated autophagy in Crohn-like metabolic enteritis of mice induced by polyunsaturated fatty acid (PUFA) excess in a western diet. Dietary PUFAs induce ATG16L1-mediated conventional autophagy in IECs, which is required for PUFA-induced chemokine production and metabolic enteritis. By transcriptomic and lipidomic profiling of IECs, we demonstrate that ATG16L1 is required for PUFA-induced inflammatory stress signaling specifically mediated by TLR2 (toll-like receptor 2) and the production of arachidonic acid metabolites. Our study identifies ATG16L1-mediated autophagy in IECs as an inflammatory hub driving metabolic enteritis, which challenges the perception of protective autophagy in the context of diet westernization.Abbreviations: AA: arachidonic acid; ATG16L1: autophagy related 16 like 1; CD: Crohn disease; CXCL1: C-X-C motif chemokine ligand 1; ER: endoplasmic reticulum; GFP: green fluorescent protein; GPX4: glutathione peroxidase 4; IBD: inflammatory bowel disease; IECs: intestinal epithelial cells; PTGS2/COX2: prostaglandin-endoperoxide synthase 2; PUFA: polyunsaturated fatty acid; SDA: stearidonic acid; TLR2: toll-like receptor 2; WT: wild-type.