WDR83/MORG1 inhibits RRAG GTPase-MTORC1 signaling to facilitate basal autophagy.

Macroautophagy/autophagy is a conserved lysosomal degradation process composed of both selective and nonselective degradation pathways. The latter occurs upon nutrient depletion. Selective autophagy exerts quality control of damaged organelles and macromolecules and is going on also under nutrient-replete conditions. Proper regulation of autophagy is vital for cellular homeostasis and prevention of disease. During nutrient availability, autophagy is inhibited by the MTORC1 signaling pathway. However, selective, basal autophagy occurs continuously. How the MTORC1 pathway is fine-tuned to facilitate basal constitutive autophagy is unclear. Recently, we identified the WD-domain repeat protein WDR83/MORG1 as a negative regulator of MTORC1 signaling allowing basal, selective autophagy. WDR83 interacts with both the Ragulator and active RRAG GTPases to prevent recruitment of the MTORC1 complex to the lysosome. Consequently, WDR83 depletion leads to hyperactivation of the MTORC1 pathway and a strong decrease in basal autophagy. As a consequence of WDR83 depletion cell proliferation and migration increase and low levels of WDR83 mRNA are correlated with poor prognosis for several cancers.

MORG1 limits mTORC1 signaling by inhibiting Rag GTPases.

Autophagy, an important quality control and recycling process vital for cellular homeostasis, is tightly regulated. The mTORC1 signaling pathway regulates autophagy under conditions of nutrient availability and scarcity. However, how mTORC1 activity is fine-tuned during nutrient availability to allow basal autophagy is unclear. Here, we report that the WD-domain repeat protein MORG1 facilitates basal constitutive autophagy by inhibiting mTORC1 signaling through Rag GTPases. Mechanistically, MORG1 interacts with active Rag GTPase complex inhibiting the Rag GTPase-mediated recruitment of mTORC1 to the lysosome. MORG1 depletion in HeLa cells increases mTORC1 activity and decreases autophagy. The autophagy receptor p62/SQSTM1 binds to MORG1, but MORG1 is not an autophagy substrate. However, p62/SQSTM1 binding to MORG1 upon re-addition of amino acids following amino acid's depletion precludes MORG1 from inhibiting the Rag GTPases, allowing mTORC1 activation. MORG1 depletion increases cell proliferation and migration. Low expression of MORG1 correlates with poor survival in several important cancers.

ATPase activity of DFCP1 controls selective autophagy.

Cellular homeostasis is governed by removal of damaged organelles and protein aggregates by selective autophagy mediated by cargo adaptors such as p62/SQSTM1. Autophagosomes can assemble in specialized cup-shaped regions of the endoplasmic reticulum (ER) known as omegasomes, which are characterized by the presence of the ER protein DFCP1/ZFYVE1. The function of DFCP1 is unknown, as are the mechanisms of omegasome formation and constriction. Here, we demonstrate that DFCP1 is an ATPase that is activated by membrane binding and dimerizes in an ATP-dependent fashion. Whereas depletion of DFCP1 has a minor effect on bulk autophagic flux, DFCP1 is required to maintain the autophagic flux of p62 under both fed and starved conditions, and this is dependent on its ability to bind and hydrolyse ATP. While DFCP1 mutants defective in ATP binding or hydrolysis localize to forming omegasomes, these omegasomes fail to constrict properly in a size-dependent manner. Consequently, the release of nascent autophagosomes from large omegasomes is markedly delayed. While knockout of DFCP1 does not affect bulk autophagy, it inhibits selective autophagy, including aggrephagy, mitophagy and micronucleophagy. We conclude that DFCP1 mediates ATPase-driven constriction of large omegasomes to release autophagosomes for selective autophagy.

TBK1 phosphorylation activates LIR-dependent degradation of the inflammation repressor TNIP1.

Limitation of excessive inflammation due to selective degradation of pro-inflammatory proteins is one of the cytoprotective functions attributed to autophagy. In the current study, we highlight that selective autophagy also plays a vital role in promoting the establishment of a robust inflammatory response. Under inflammatory conditions, here TLR3-activation by poly(I:C) treatment, the inflammation repressor TNIP1 (TNFAIP3 interacting protein 1) is phosphorylated by Tank-binding kinase 1 (TBK1) activating an LIR motif that leads to the selective autophagy-dependent degradation of TNIP1, supporting the expression of pro-inflammatory genes and proteins. This selective autophagy efficiently reduces TNIP1 protein levels early (0-4 h) upon poly(I:C) treatment to allow efficient initiation of the inflammatory response. At 6 h, TNIP1 levels are restored due to increased transcription avoiding sustained inflammation. Thus, similarly as in cancer, autophagy may play a dual role in controlling inflammation depending on the exact state and timing of the inflammatory response.

NBR1: The archetypal selective autophagy receptor.

NBR1 was discovered as an autophagy receptor not long after the first described vertebrate autophagy receptor p62/SQSTM1. Since then, p62 has currently been mentioned in >10,000 papers on PubMed, while NBR1 is mentioned in <350 papers. Nonetheless, evolutionary analysis reveals that NBR1, and likely also selective autophagy, was present already in the last eukaryotic common ancestor (LECA), while p62 appears first in the early Metazoan lineage. Furthermore, yeast-selective autophagy receptors Atg19 and Atg34 represent NBR1 homologs. NBR1 is the main autophagy receptor in plants that do not contain p62, while most animal taxa contain both NBR1 and p62. Mechanistic studies are starting to shed light on the collaboration between mammalian NBR1 and p62 in the autophagic degradation of protein aggregates (aggrephagy). Several domains of NBR1 are involved in cargo recognition, and the list of known substrates for NBR1-mediated selective autophagy is increasing. Lastly, roles of NBR1 in human diseases such as proteinopathies and cancer are emerging.

Autophagy in major human diseases.

Autophagy is a core molecular pathway for the preservation of cellular and organismal homeostasis. Pharmacological and genetic interventions impairing autophagy responses promote or aggravate disease in a plethora of experimental models. Consistently, mutations in autophagy-related processes cause severe human pathologies. Here, we review and discuss preclinical data linking autophagy dysfunction to the pathogenesis of major human disorders including cancer as well as cardiovascular, neurodegenerative, metabolic, pulmonary, renal, infectious, musculoskeletal, and ocular disorders.

Phosphorylation of the LIR Domain of SCOC Modulates ATG8 Binding Affinity and Specificity.

Autophagy is a highly conserved degradative pathway, essential for cellular homeostasis and implicated in diseases including cancer and neurodegeneration. Autophagy-related 8 (ATG8) proteins play a central role in autophagosome formation and selective delivery of cytoplasmic cargo to lysosomes by recruiting autophagy adaptors and receptors. The LC3-interacting region (LIR) docking site (LDS) of ATG8 proteins binds to LIR motifs present in autophagy adaptors and receptors. LIR-ATG8 interactions can be highly selective for specific mammalian ATG8 family members (LC3A-C, GABARAP, and GABARAPL1-2) and how this specificity is generated and regulated is incompletely understood. We have identified a LIR motif in the Golgi protein SCOC (short coiled-coil protein) exhibiting strong binding to GABARAP, GABARAPL1, LC3A and LC3C. The residues within and surrounding the core LIR motif of the SCOC LIR domain were phosphorylated by autophagy-related kinases (ULK1-3, TBK1) increasing specifically LC3 family binding. More distant flanking residues also contributed to ATG8 binding. Loss of these residues was compensated by phosphorylation of serine residues immediately adjacent to the core LIR motif, indicating that the interactions of the flanking LIR regions with the LDS are important and highly dynamic. Our comprehensive structural, biophysical and biochemical analyses support and provide novel mechanistic insights into how phosphorylation of LIR domain residues regulates the affinity and binding specificity of ATG8 proteins towards autophagy adaptors and receptors.

SIRT1 - a new mammalian substrate of nuclear autophagy.

Macroautophagic/autophagic degradation of nuclear components (or nuclear autophagy) is a poorly understood area in autophagy research. We previously reported the nuclear lamina protein LMNB1 (lamin B1) as a nuclear autophagy substrate in primary human cells, stimulating the investigation of nuclear autophagy in the mammalian system. We recently reported the sirtuin protein SIRT1 as a new selective substrate of nuclear autophagy in senescence and aging. Upon senescence of primary human cells, SIRT1 degradation is mediated by a direct nuclear SIRT1-LC3 interaction, followed by nucleus-to-cytoplasm shuttling of SIRT1 and autophagosome-lysosome degradation. In vivo, SIRT1 is downregulated by lysosomes in hematopoietic and immune organs upon natural aging in mice and in aged human T cells. Our study identified another substrate of nuclear autophagy and suggests a new strategy to promote SIRT1-mediated health benefits by suppressing its autophagic degradation.Abbreviations: HSPC: hematopoietic stem and progenitor cells; NAD+: nicotinamide adenine dinucleotide; SASP: senescence-associated secretory phenotype.

NIMA-related kinase 9-mediated phosphorylation of the microtubule-associated LC3B protein at Thr-50 suppresses selective autophagy of p62/sequestosome 1.

Human ATG8 family proteins (ATG8s) are active in all steps of the macroautophagy pathway, and their lipidation is essential for autophagosome formation. Lipidated ATG8s anchored to the outer surface of the phagophore serve as scaffolds for binding of other core autophagy proteins and various effector proteins involved in trafficking or fusion events, whereas those at the inner surface are needed for assembly of selective autophagy substrates. Their scaffolding role depends on specific interactions between the LC3-interacting region (LIR) docking site (LDS) in ATG8s and LIR motifs in various interaction partners. LC3B is phosphorylated at Thr-50 within the LDS by serine/threonine kinase (STK) 3 and STK4. Here, we identified LIR motifs in STK3 and atypical protein kinase Cζ (PKCζ) and never in mitosis A (NIMA)-related kinase 9 (NEK9). All three kinases phosphorylated LC3B Thr-50 in vitro A phospho-mimicking substitution of Thr-50 impaired binding of several LIR-containing proteins, such as ATG4B, FYVE, and coiled-coil domain-containing 1 (FYCO1), and autophagy cargo receptors p62/sequestosome 1 (SQSTM1) and neighbor of BRCA1 gene (NBR1). NEK9 knockdown or knockout enhanced degradation of the autophagy receptor and substrate p62. Of note, the suppression of p62 degradation was mediated by NEK9-mediated phosphorylation of LC3B Thr-50. Consistently, reconstitution of LC3B-KO cells with the phospho-mimicking T50E variant inhibited autophagic p62 degradation. PKCζ knockdown did not affect autophagic p62 degradation, whereas STK3/4 knockouts inhibited autophagic p62 degradation independently of LC3B Thr-50 phosphorylation. Our findings suggest that NEK9 suppresses LC3B-mediated autophagy of p62 by phosphorylating Thr-50 within the LDS of LC3B.

SQSTM-1/p62 potentiates HTLV-1 Tax-mediated NF-κB activation through its ubiquitin binding function.

The NF-κB pathway is constitutively activated in adult T cell leukemia, an aggressive malignancy caused by Human T Leukemia Virus type 1 (HTLV-1). The viral oncoprotein Tax triggers this constitutive activation by interacting with the ubiquitin-rich IKK complex. We previously demonstrated that Optineurin and TAX1BP1, two members of the ubiquitin-binding, Sequestosome-1 (SQSTM-1/p62)-like selective autophagy receptor family, are involved in Tax-mediated NF-κB signaling. Here, using a proximity-dependent biotinylation approach (BioID), we identify p62 as a new candidate partner of Tax and confirm the interaction in infected T cells. We then demonstrate that p62 knock-out in MEF cells as well as p62 knock-down in HEK293T cells significantly reduces Tax-mediated NF-κB activity. We further show that although p62 knock-down does not alter NF-κB activation in Jurkat T cells nor in infected T cells, p62 does potentiate Tax-mediated NF-κB activity upon over-expression in Jurkat T cells. We next show that p62 associates with the Tax/IKK signalosome in cells, and identify the 170-206 domain of p62 as sufficient for the direct, ubiquitin-independent interaction with Tax. However, we observe that this domain is dispensable for modulating Tax activity in cells, and functional analysis of p62 mutants indicates that p62 could potentiate Tax activity in cells by facilitating the association of ubiquitin chains with the Tax/IKK signalosome. Altogether, our results identify p62 as a new ubiquitin-dependent modulator of Tax activity on NF-κB, further highlighting the importance of ubiquitin in the signaling activity of the viral Tax oncoprotein.

Nrf2 and SQSTM1/p62 jointly contribute to mesenchymal transition and invasion in glioblastoma.

Accumulating evidence suggests that constitutively active Nrf2 has a pivotal role in cancer as it induces pro-survival genes that promote cancer cell proliferation and chemoresistance. The mechanisms of Nrf2 dysregulation and functions in cancer have not been fully characterized. Here, we jointly analyzed the Broad-Novartis Cancer Cell Line Encyclopedia (CCLE) and the Cancer Genome Atlas (TCGA) multi-omics data in order to identify cancer types where Nrf2 activation is present. We found that Nrf2 is hyperactivated in a subset of glioblastoma (GBM) patients, whose tumors display a mesenchymal subtype, and uncover several different mechanisms contributing to increased Nrf2 activity. Importantly, we identified a positive feedback loop between SQSTM1/p62 and Nrf2 as a mechanism for activation of the Nrf2 pathway. We also show that autophagy and serine/threonine signaling regulates p62 mediated Keap1 degradation. Our results in glioma cell lines indicate that both Nrf2 and p62 promote proliferation, invasion and mesenchymal transition. Finally, Nrf2 activity was associated with decreased progression free survival in TCGA GBM patient samples, suggesting that treatments have limited efficacy if this transcription factor is overactivated. Overall, our findings place Nrf2 and p62 as the key components of the mesenchymal subtype network, with implications to tumorigenesis and treatment resistance. Thus, Nrf2 activation could be used as a surrogate prognostic marker in mesenchymal subtype GBMs. Furthermore, strategies aiming at either inhibiting Nrf2 or exploiting Nrf2 hyperactivity for targeted gene therapy may provide novel treatment options for this subset of GBM.

Members of the autophagy class III phosphatidylinositol 3-kinase complex I interact with GABARAP and GABARAPL1 via LIR motifs.

Autophagosome formation depends on a carefully orchestrated interplay between membrane-associated protein complexes. Initiation of macroautophagy/autophagy is mediated by the ULK1 (unc-51 like autophagy activating kinase 1) protein kinase complex and the autophagy-specific class III phosphatidylinositol 3-kinase complex I (PtdIns3K-C1). The latter contains PIK3C3/VPS34, PIK3R4/VPS15, BECN1/Beclin 1 and ATG14 and phosphorylates phosphatidylinositol to generate phosphatidylinositol 3-phosphate (PtdIns3P). Here, we show that PIK3C3, BECN1 and ATG14 contain functional LIR motifs and interact with the Atg8-family proteins with a preference for GABARAP and GABARAPL1. High resolution crystal structures of the functional LIR motifs of these core components of PtdIns3K-C1were obtained. Variation in hydrophobic pocket 2 (HP2) may explain the specificity for the GABARAP family. Mutation of the LIR motif in ATG14 did not prevent formation of the PtdIns3K-C1 complex, but blocked colocalization with MAP1LC3B/LC3B and impaired mitophagy. The ULK-mediated phosphorylation of S29 in ATG14 was strongly dependent on a functional LIR motif in ATG14. GABARAP-preferring LIR motifs in PIK3C3, BECN1 and ATG14 may, via coincidence detection, contribute to scaffolding of PtdIns3K-C1 on membranes for efficient autophagosome formation. Abbreviations: ATG: autophagy-related; BafA1: bafilomycin A1; GABARAP: GABA type A receptor-associated protein; GABARAPL1: GABA type A receptor associated protein like 1; GFP: enhanced green fluorescent protein; KO: knockout; LDS: LIR docking site; LIR: LC3-interacting region; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; PIK3C3: phosphatidylinositol 3-kinase catalytic subunit type 3; PIK3R4: phosphoinositide-3-kinase regulatory subunit 4; PtdIns3K: phosphatidylinositol 3-kinase; PtdIns3P: phosphatidylinositol-3-phosphate; SQSTM1/p62: sequestosome 1; VPS: Vacuolar protein sorting; ULK: unc-51 like autophagy activating kinase.

Use of Peptide Arrays for Identification and Characterization of LIR Motifs.

The mammalian ATG8 proteins (LC3A-C/GABARAP, GABARAPL1, and GABARAPL2) are small ubiquitin-like proteins critically involved in macroautophagy. Their processed C-termini are posttranslationally conjugated to a phosphatidylethanolamine moiety, enabling their insertion into the lipid bilayers of both the inner and outer membranes of the forming autophagosomes. The ATG8s bind a diverse selection of proteins including cargo receptors for selective autophagy, members of the core autophagy machinery, and other proteins involved in formation, transport, and maturation (fusion to lysosomes) of autophagosomes. Protein binding to the ATG8s is in most cases mediated by short, conserved sequence motifs known as LC3-interacting regions (LIRs). Here, we present a protocol for identifying putative LIR motifs in a whole protein sequence using peptide arrays generated by SPOT synthesis on nitrocellulose membranes. The use of two-dimensional peptide arrays allows for further identification of specific residues critical for LIR binding.

Bicaudal D1 impairs autophagosome maturation in chronic obstructive pulmonary disease.

Bicaudal D1 (BICD1), an adaptor for the dynein-dynactin motor complex, has been identified as a susceptibility gene in chronic obstructive pulmonary disease (COPD). Autophagy, an essential cellular homeostasis process, is defective in COPD, in which oxidative stress-induced misfolded proteins accumulate into toxic aggregates dependent on the accumulation of the autophagic cargo receptor p62. Defective autophagy can be caused by mutations in the dynein and dynactin motor complex suggesting a possible link between BICD1 and defective autophagy in COPD. BICD1 levels were measured in peripheral lung tissue from COPD patients together with markers of autophagy and found to be increased in COPD together with autophagosomes, p62 and p62 oligomers. In vitro exposure of bronchial epithelial cells to cigarette smoke extracts (CSEs) revealed that high concentrations of CSE induced defective autophagosome maturation with accumulation of BICD1, p62 and ubiquitin-associated p62 oligomers. This was confirmed in vivo using CS-exposed mice. Furthermore, we identified that formation of CS-induced p62 oligomers required an interaction with Keap1. Overexpression and ablation of BICD1 confirmed that increased BICD1 negatively regulates autophagosome maturation inducing accumulation of p62 and p62 oligomers and that it can be reversed by cardiac glycosides. We conclude that defective autophagosome maturation in COPD is caused by oxidative stress-mediated BICD1 accumulation.

Starvation induces rapid degradation of selective autophagy receptors by endosomal microautophagy.

It is not clear to what extent starvation-induced autophagy affects the proteome on a global scale and whether it is selective. In this study, we report based on quantitative proteomics that cells during the first 4 h of acute starvation elicit lysosomal degradation of up to 2-3% of the proteome. The most significant changes are caused by an immediate autophagic response elicited by shortage of amino acids but executed independently of mechanistic target of rapamycin and macroautophagy. Intriguingly, the autophagy receptors p62/SQSTM1, NBR1, TAX1BP1, NDP52, and NCOA4 are among the most efficiently degraded substrates. Already 1 h after induction of starvation, they are rapidly degraded by a process that selectively delivers autophagy receptors to vesicles inside late endosomes/multivesicular bodies depending on the endosomal sorting complex required for transport III (ESCRT-III). Our data support a model in which amino acid deprivation elicits endocytosis of specific membrane receptors, induction of macroautophagy, and rapid degradation of autophagy receptors by endosomal microautophagy.

Zonda is a novel early component of the autophagy pathway in Drosophila.

Autophagy is an evolutionary conserved process by which eukaryotic cells undergo self-digestion of cytoplasmic components. Here we report that a novel Drosophila immunophilin, which we have named Zonda, is critically required for starvation-induced autophagy. We show that Zonda operates at early stages of the process, specifically for Vps34-mediated phosphatidylinositol 3-phosphate (PI3P) deposition. Zonda displays an even distribution under basal conditions and, soon after starvation, nucleates in endoplasmic reticulum-associated foci that colocalize with omegasome markers. Zonda nucleation depends on Atg1, Atg13, and Atg17 but does not require Vps34, Vps15, Atg6, or Atg14. Zonda interacts physically with Atg1 through its kinase domain, as well as with Atg6 and Vps34. We propose that Zonda is an early component of the autophagy cascade necessary for Vps34-dependent PI3P deposition and omegasome formation.

FKBP8 recruits LC3A to mediate Parkin-independent mitophagy.

Mitophagy, the selective removal of damaged or excess mitochondria by autophagy, is an important process in cellular homeostasis. The outer mitochondrial membrane (OMM) proteins NIX, BNIP3, FUNDC1, and Bcl2-L13 recruit ATG8 proteins (LC3/GABARAP) to mitochondria during mitophagy. FKBP8 (also known as FKBP38), a unique member of the FK506-binding protein (FKBP) family, is similarly anchored in the OMM and acts as a multifunctional adaptor with anti-apoptotic activity. In a yeast two-hybrid screen, we identified FKBP8 as an ATG8-interacting protein. Here, we map an N-terminal LC3-interacting region (LIR) motif in FKBP8 that binds strongly to LC3A both in vitro and in vivo FKBP8 efficiently recruits lipidated LC3A to damaged mitochondria in a LIR-dependent manner. The mitophagy receptors BNIP3 and NIX in contrast are unable to mediate an efficient recruitment of LC3A even after mitochondrial damage. Co-expression of FKBP8 with LC3A profoundly induces Parkin-independent mitophagy. Strikingly, even when acting as a mitophagy receptor, FKBP8 avoids degradation by escaping from mitochondria. In summary, this study identifies novel roles for FKBP8 and LC3A, which act together to induce mitophagy.

ATG4B contains a C-terminal LIR motif important for binding and efficient cleavage of mammalian orthologs of yeast Atg8.

The cysteine protease ATG4B cleaves off one or more C-terminal residues of the inactive proform of proteins of the ortholog and paralog LC3 and GABARAP subfamilies of yeast Atg8 to expose a C-terminal glycine that is conjugated to phosphatidylethanolamine during autophagosome formation. We show that ATG4B contains a C-terminal LC3-interacting region (LIR) motif important for efficient binding to and cleavage of LC3 and GABARAP proteins. We solved the crystal structures of the GABARAPL1-ATG4B C-terminal LIR complex. Analyses of the structures and in vitro binding assays, using specific point mutants, clearly showed that the ATG4B LIR binds via electrostatic-, aromatic HP1 and hydrophobic HP2 pocket interactions. Both these interactions and the catalytic site-substrate interaction contribute to binding between LC3s or GABARAPs and ATG4B. We also reveal an unexpected role for ATG4B in stabilizing the unlipidated forms of GABARAP and GABARAPL1. In mouse embryonic fibroblast (MEF) atg4b knockout cells, GABARAP and GABARAPL1 were unstable and degraded by the proteasome. Strikingly, the LIR motif of ATG4B was required for stabilization of the unlipidated forms of GABARAP and GABARAPL1 in cells.

Microenvironmental autophagy promotes tumour growth.

As malignant tumours develop, they interact intimately with their microenvironment and can activate autophagy, a catabolic process which provides nutrients during starvation. How tumours regulate autophagy in vivo and whether autophagy affects tumour growth is controversial. Here we demonstrate, using a well characterized Drosophila melanogaster malignant tumour model, that non-cell-autonomous autophagy is induced both in the tumour microenvironment and systemically in distant tissues. Tumour growth can be pharmacologically restrained using autophagy inhibitors, and early-stage tumour growth and invasion are genetically dependent on autophagy within the local tumour microenvironment. Induction of autophagy is mediated by Drosophila tumour necrosis factor and interleukin-6-like signalling from metabolically stressed tumour cells, whereas tumour growth depends on active amino acid transport. We show that dormant growth-impaired tumours from autophagy-deficient animals reactivate tumorous growth when transplanted into autophagy-proficient hosts. We conclude that transformed cells engage surrounding normal cells as active and essential microenvironmental contributors to early tumour growth through nutrient-generating autophagy.

TRIM17 contributes to autophagy of midbodies while actively sparing other targets from degradation.

TRIM proteins contribute to selective autophagy, a process whereby cells target specific cargo for autophagic degradation. In a previously reported screen, TRIM17 acted as a prominent inhibitor of bulk autophagy, unlike the majority of TRIMs, which had positive roles. Nevertheless, TRIM17 showed biochemical hallmarks of autophagy-inducing TRIMs. To explain this paradox, here, we investigated how TRIM17 inhibits selective autophagic degradation of a subset of targets while promoting degradation of others. We traced the inhibitory function of TRIM17 to its actions on the anti-autophagy protein Mcl-1, which associates with and inactivates Beclin 1. TRIM17 expression stabilized Mcl-1-Beclin-1 complexes. Despite its ability to inhibit certain types of selective autophagy, TRIM17 promoted the removal of midbodies, remnants of the cell division machinery that are known autophagy targets. The selective loss of anti-autophagy Mcl-1 from TRIM17-Beclin-1 complexes at midbodies correlated with the ability of TRIM17 to promote midbody removal. This study further expands the roles of TRIMs in regulating selective autophagy by showing that a single TRIM can, depending upon a target, either positively or negatively regulate autophagy.