RACK1 depletion in the ribosome induces selective translation for non-canonical autophagy

Sporoderm-broken spores of Ganoderma lucidum modulate hepatoblastoma malignancy by regulating RACK1-mediated autophagy and tumour immunity

Hepatoblastoma (HB), a primary liver tumour, is notorious for its high metastatic potential and poor prognosis. Ganoderma lucidum, an edible mushroom species utilized in traditional Chinese medicine for addressing various tumour types, presents an intriguing avenue for HB treatment. However, the effectiveness of G. lucidum in managing HB and its underlying molecular mechanism necessitates further exploration. Standard in vitro assays were conducted to evaluate the impact of sporoderm-broken spores of G. lucidum (SBSGL) on the malignant characteristics of HB cells. The mechanism of SBSGL in treating HB and its tumour immunomodulatory effects were explored and validated by various experiments, including immunoprecipitation, Western blotting, mRFP-GFP-LC3 adenovirus transfection and co-localization analysis, as well as verified with in vivo experiments in this regard. The results showed that SBSGL effectively inhibited the malignant traits of HB cells and suppressed the O-GlcNAcylation of RACK1, thereby reducing its expression. In addition, SBSGL inhibited immune checkpoints and regulated cytokines. In conclusion, SBSGL had immunomodulatory effects and regulated the malignancy and autophagy of HB by regulating the O-GlcNAcylation of RACK1. These findings suggest that SBSGL holds promise as a potential anticancer drug for HB treatment.

Autophagy-modulating biomaterials: multifunctional weapons to promote tissue regeneration

Autophagy is a self-renewal mechanism that maintains homeostasis and can promote tissue regeneration by regulating inflammation, reducing oxidative stress and promoting cell differentiation. The interaction between biomaterials and tissue cells significantly affects biomaterial-tissue integration and tissue regeneration. In recent years, it has been found that biomaterials can affect various processes related to tissue regeneration by regulating autophagy. The utilization of biomaterials in a controlled environment has become a prominent approach for enhancing the tissue regeneration capabilities. This involves the regulation of autophagy in diverse cell types implicated in tissue regeneration, encompassing the modulation of inflammatory responses, oxidative stress, cell differentiation, proliferation, migration, apoptosis, and extracellular matrix formation. In addition, biomaterials possess the potential to serve as carriers for drug delivery, enabling the regulation of autophagy by either activating or inhibiting its processes. This review summarizes the relationship between autophagy and tissue regeneration and discusses the role of biomaterial-based autophagy in tissue regeneration. In addition, recent advanced technologies used to design autophagy-modulating biomaterials are summarized, and rational design of biomaterials for providing controlled autophagy regulation via modification of the chemistry and surface of biomaterials and incorporation of cells and molecules is discussed. A better understanding of biomaterial-based autophagy and tissue regeneration, as well as the underlying molecular mechanisms, may lead to new possibilities for promoting tissue regeneration. Video Abstract.

Customization of the translational complex regulates mRNA-specific translation to control CNS regeneration

In the adult mammalian central nervous system (CNS), axons fail to regenerate spontaneously after injury because of a combination of extrinsic and intrinsic factors. Despite recent advances targeting the intrinsic regenerative properties of adult neurons, the molecular mechanisms underlying axon regeneration are not fully understood. Here, we uncover a regulatory mechanism that controls the expression of key proteins involved in regeneration at the translational level. Our results show that mRNA-specific translation is critical for promoting axon regeneration. Indeed, we demonstrate that specific ribosome-interacting proteins, such as the protein Huntingtin (HTT), selectively control the translation of a specific subset of mRNAs. Moreover, modulating the expression of these translationally regulated mRNAs is crucial for promoting axon regeneration. Altogether, our findings highlight that selective translation through the customization of the translational complex is a key mechanism of axon regeneration with major implications in the development of therapeutic strategies for CNS repair.

De-centralizing the Central Dogma: mRNA translation in space and time

As our understanding of the cell interior has grown, we have come to appreciate that most cellular operations are localized, that is, they occur at discrete and identifiable locations or domains. These cellular domains contain enzymes, machines, and other components necessary to carry out and regulate these localized operations. Here, we review these features of one such operation: the localization and translation of mRNAs within subcellular compartments observed across cell types and organisms. We describe the conceptual advantages and the "ingredients" and mechanisms of local translation. We focus on the nature and features of localized mRNAs, how they travel and get localized, and how this process is regulated. We also evaluate our current understanding of protein synthesis machines (ribosomes) and their cadre of regulatory elements, that is, the translation factors.

Characterization of the RACK1 gene of Aips cerana cerana and its role in adverse environmental stresses

Receptors for Activated C Kinase 1 (RACK1s) are a kind of multifunction scaffold protein that plays an important role in cell signal transductions and animal development. However, the function of RACK1 in the Chinese honeybee Apis cerana cerana is little known. Here, we isolated and identified a RACK1 gene from Apis cerana cerana, named AccRACK1. By bioinformatic analysis, we revealed a high nucleic acid homology between AccRACK1 and RACK1 of Apis cerana. RT-qPCR analyses demonstrated AccRACK1 was mostly expressed in 3rd instar larvae, darked-eyed pupae and adults (one and thirty days post-emergence), suggesting it might participate in the development of A. cerana cerana. Moreover, the expression of AccRACK1 was highest in the thorax, followed by the venom gland. Compared to the blank control group, AccRACK1 was induced by 24 and 44 °C, HgCl2 and pesticides (paraquat, pyridaben and methomyl) but inhibited by 14 °C, H2O2, UV light and cyhalothrin. Additionally, 0.05, 0.1, 1, 5 and 10 mg/ml PPN (juvenile hormone analogue pyriproxyfen) could promote the expression of AccRACK1, with 1 mg/ml showing the highest upregulation, suggesting it was regulated by hormones. Further study found that after knockdown of AccRACK1 by RNAi, the expression of the eukaryotic initiation factor 6 of A. cerana cerana (AcceIF6), an initiation factor regulating the initiation of translation, was inhibited, indicating AccRACK1 might affect cellular responses by translation. These findings, taken together, suggest AccRACK1 is involved in the development and responses to abiotic stresses of A. cerana cerana, and therefore, it may be of critical importance to the survival of A. cerana cerana.

RACK1 Associates with RNA-Binding Proteins Vigilin and SERBP1 to Facilitate Dengue Virus Replication

Dengue virus (DENV) is a mosquito-borne flavivirus responsible for dengue disease, a major human health concern for which no effective treatment is available. DENV relies heavily on the host cellular machinery for productive infection. Here, we show that the scaffold protein RACK1, which is part of the DENV replication complex, mediates infection by binding to the 40S ribosomal subunit. Mass spectrometry analysis of RACK1 partners coupled to an RNA interference screen-identified Vigilin and SERBP1 as DENV host-dependency factors. Both are RNA-binding proteins that interact with the DENV genome. Genetic ablation of Vigilin or SERBP1 rendered cells poorly susceptible to DENV, as well as related flaviviruses, by hampering the translation and replication steps. Finally, we established that a Vigilin or SERBP1 mutant lacking RACK1 binding but still interacting with the viral RNA is unable to mediate DENV infection. We propose that RACK1 recruits Vigilin and SERBP1, linking the DENV genome to the translation machinery for efficient infection. IMPORTANCE We recently identified the scaffolding RACK1 protein as an important host-dependency factor for dengue virus (DENV), a positive-stranded RNA virus responsible for the most prevalent mosquito-borne viral disease worldwide. Here, we have performed the first RACK1 interactome in human cells and identified Vigilin and SERBP1 as DENV host-dependency factors. Both are RNA-binding proteins that interact with the DENV RNA to regulate viral replication. Importantly, Vigilin and SERBP1 interact with RACK1 and the DENV viral RNA (vRNA) to mediate viral replication. Overall, our results suggest that RACK1 acts as a binding platform at the surface of the 40S ribosomal subunit to recruit Vigilin and SERBP1, which may therefore function as linkers between the viral RNA and the translation machinery to facilitate infection.

Specialised ribosomes as versatile regulators of gene expression

The ribosome has long been thought to be a homogeneous cellular machine that constitutively and globally synthesises proteins from mRNA. However, recent studies have revealed that ribosomes are highly heterogeneous, dynamic macromolecular complexes with specialised roles in translational regulation in many organisms across the kingdoms. In this review, we summarise the current understanding of ribosome heterogeneity and the specialised functions of heterogeneous ribosomes. We also discuss specialised translation systems that utilise orthogonal ribosomes.

Preventing translational inhibition from ribosomal protein insufficiency by a herpes simplex virus-encoded ribosome-associated protein

In addition to being required for protein synthesis, ribosomes and ribosomal proteins (RPs) also regulate messenger RNA translation in uninfected and virus-infected cells. By individually depleting 85 RPs using RNA interference, we found that overall protein synthesis in uninfected primary fibroblasts was more sensitive to RP depletion than those infected with herpes simplex virus-1 (HSV-1). Although representative RP depletion (uL3, uS4, uL5) inhibited protein synthesis in cells infected with two different DNA viruses (human cytomegalovirus, vaccinia virus), HSV-1-infected cell protein synthesis unexpectedly endured and required a single virus-encoded gene product, VP22. During individual RP insufficiency, VP22-expressing HSV-1 replicated better than a VP22-deficient variant. Furthermore, VP22 promotes polysome accumulation in virus-infected cells when uL3 or ribosome availability is limiting and cosediments with initiating and elongating ribosomes in infected and uninfected cells. This identifies VP22 as a virus-encoded, ribosome-associated protein that compensates for RP insufficiency to support viral protein synthesis and replication. Moreover, it reveals an unanticipated class of virus-encoded, ribosome-associated effectors that reduce the dependence of protein synthesis upon host RPs and broadly support translation during physiological stress such as infection.

Negative charge in the RACK1 loop broadens the translational capacity of the human ribosome

Although the roles of initiation factors, RNA binding proteins, and RNA elements in regulating translation are well defined, how the ribosome functionally diversifies remains poorly understood. In their human hosts, poxviruses phosphorylate serine 278 (S²⁷⁸) at the tip of a loop domain in the small subunit ribosomal protein RACK1, thereby mimicking negatively charged residues in the RACK1 loops of dicot plants and protists to stimulate translation of transcripts with 5′ poly(A) leaders. However, how a negatively charged RACK1 loop affects ribosome structure and its broader translational output is not known. Here, we show that although ribotoxin-induced stress signaling and stalling on poly(A) sequences are unaffected, negative charge in the RACK1 loop alters the swivel motion of the 40S head domain in a manner similar to several internal ribosome entry sites (IRESs), confers resistance to various protein synthesis inhibitors, and broadly supports noncanonical modes of translation.

How ribosomes functionally diversify to selectively control translation is only beginning to be understood. Rollins et al. show that negative charge in a loop domain of the small subunit ribosomal protein RACK1 increases the swiveling motion of the 40S head and broadens the translational capacity of the human ribosome.

The role of RNA-binding and ribosomal proteins as specific RNA translation regulators in cellular differentiation and carcinogenesis

Tight control of mRNA expression is required for cell differentiation; imbalanced regulation may lead to developmental disorders and cancer. The activity of the translational machinery (including ribosomes and translation factors) regulates the rate (slow or fast) of translation of encoded proteins, and the quality of these proteins highly depends on which mRNAs are available for translation. Specific RNA-binding and ribosomal proteins seem to play a key role in controlling gene expression to determine the differentiation fate of the cell. This demonstrates the important role of RNA-binding proteins, specific ribosome-binding proteins and microRNAs as key molecules in controlling the specific proteins required for the differentiation or dedifferentiation of cells. This delicate balance between specific proteins (in terms of quality and availability) and post-translational modifications occurring in the cytoplasm is crucial for cell differentiation, dedifferentiation and oncogenic potential. In this review, we report how defects in the regulation of mRNA translation can be dependent on specific proteins and can induce an imbalance between differentiation and dedifferentiation in cell fate determination.

RACK1 Mediates NLRP3 Inflammasome Activation by Promoting NLRP3 Active Conformation and Inflammasome Assembly

The NLRP3 inflammasome, a critical component of the innate immune system, induces caspase-1 activation and interleukin (IL)-1β maturation in response to microbial infection and cellular damage. However, aberrant activation of the NLRP3 inflammasome contributes to the pathogenesis of several inflammatory disorders, including cryopyrin-associated periodic syndromes, Alzheimer's disease, type 2 diabetes, and atherosclerosis. Here, we identify the receptor for activated protein C kinase 1 (RACK1) as a component of the NLRP3 complexes in macrophages. RACK1 interacts with NLRP3 and NEK7 but not ASC. Suppression of RACK1 expression abrogates caspase-1 activation and IL-1β release in response to NLRP3- but not NLRC4- or AIM2-activating stimuli. This RACK1 function is independent of its ribosomal binding activity. Mechanistically, RACK1 promotes the active conformation of NLRP3 induced by activating stimuli and subsequent inflammasome assembly. These results demonstrate that RACK1 is a critical mediator for NLRP3 inflammasome activation.

Ribosomes as a nexus between translation and cancer progression: Focus on ribosomal Receptor for Activated C Kinase 1 (RACK1) in breast cancer

Ribosomes coordinate spatiotemporal control of gene expression, contributing to the acquisition and maintenance of cancer phenotype. The link between ribosomes and cancer is found in the roles of individual ribosomal proteins in tumorigenesis and cancer progression, including the ribosomal protein, receptor for activated C kinase 1 (RACK1). RACK1 regulates cancer cell invasion and is localized in spreading initiation centres, structural adhesion complexes containing RNA binding proteins and poly-adenylated mRNAs that suggest a local translation process. As RACK1 is a ribosomal protein directly involved in translation and in breast cancer progression, we propose a new molecular mechanism for breast cancer cell migration and invasion, which considers the molecular differences between epithelial and mesenchymal cell profiles in order to characterize and provide novel targets for therapeutic strategies. Hence, we provide an analysis on how ribosomes translate cancer progression with a final focus on the ribosomal protein RACK1 in breast cancer.

Autophagy in cancer: Recent advances and future directions

Autophagy is being explored as a potential therapeutic target for enhancing the cytotoxic effects of chemotherapeutic regimens in various malignancies. Autophagy plays a very important role in cancer pathogenesis. Here, we discuss the updates on the modulation of autophagy via dynamic interactions with different organelles and the exploitation of selective autophagy for exploring therapeutic strategies. We further discuss the role of autophagy inhibitors in cancer preclinical and clinical trials, novel autophagy inhibitors, and challenges likely to be faced by clinicians while inducting autophagy modulators in clinical practice.

Autophagy Regulation by the Translation Machinery and Its Implications in Cancer

Various metabolic pathways and molecular processes in the cell act intertwined, and dysregulating the interplay between some of them may lead to cancer. It is only recently that defects in the translation process, i.e., the synthesis of proteins by the ribosome using a messenger (m)RNA as a template and translation factors, have begun to gain strong attention as a cause of autophagy dysregulation with effects in different maladies, including cancer. Autophagy is an evolutionarily conserved catabolic process that degrades cytoplasmic elements in lysosomes. It maintains cellular homeostasis and preserves cell viability under various stress conditions, which is crucial for all eukaryotic cells. In this review, we discuss recent advances shedding light on the crosstalk between the translation and the autophagy machineries and its impact on tumorigenesis. We also summarize how this interaction is being the target for novel therapies to treat cancer.

Deleting key autophagy elongation proteins induces acquirement of tumor-associated phenotypes via ISG15

Autophagy is a cellular catabolic process that maintains intracellular homeostasis using lysosomal degradation systems. We demonstrate that inhibiting autophagy by depleting essential autophagy elongation proteins, Atg5 or Atg7, induces ISG15 expression through STING-mediated cytosolic dsDNA response. Genome stability is impaired in ATG5- or ATG7-depleted cells, and thus, double-strand breakages of DNA increase and cytosolic dsDNA accumulates. Accumulated cytosolic dsDNA induces the STING pathway to activate type I IFN signals which induce STAT1 activity and downregulate ATF3. When depletion of ATG5 or ATG7 inhibits autophagy, ATF3 is downregulated and STAT1 is upregulated. Furthermore, inhibiting autophagy induces ISG15 expression through STAT1 activation, which promotes acquisition of tumor-associated phenotypes such as migration, invasion, and proliferation. In conclusion, it appears that via the STING-mediated cytosolic dsDNA response, the STAT1-ISG15 axis mediates the relationship between autophagy and the immune system in relation to tumor progression. Moreover, combined with autophagy control, regulating ISG15 expression could be a novel strategy for cancer immunotherapy.

Communication between RACK1/Asc1 and uS3 (Rps3) is essential for RACK1/Asc1 function in yeast Saccharomyces cerevisiae

The receptor for activated c-kinase (RACK1, Asc1 in yeast) is a eukaryotic ribosomal protein located in the head region of the 40S subunit near the mRNA exit channel. This WD-repeat β-propeller protein acts as a signaling molecule and is involved in metabolic regulation, cell cycle progression, and translational control. However, the exact details of the RACK1 recruitment and stable association with the 40S ribosomal subunit remain only partially known. X-ray analyses of the yeast, Saccharomyces cerevisiae, ribosome revealed that the RACK1 propeller blade (4-5) interacts with the eukaryote-specific C-terminal domain (CTD) of ribosomal protein S3 (uS3 family). To check the functional significance of this interaction, we generated mutant yeast strains harboring C-terminal deletions of uS3. We found that deletion of the 20 C-terminal residues (interacting with blade 4-5) from the uS3-CTD abrogates RACK1 binding to the ribosome. Strains with truncated uS3-CTD exhibited compromised cellular growth and protein synthesis similar to that of RACK1Δ strain, thus suggesting that the uS3-CTD is crucial not only for the recruitment and association of RACK1 with the ribosome, but also for its intracellular function. We suggest that eukaryote-specific RACK1-uS3 interaction has evolved to act as a link between the ribosome and the cellular signaling pathways.

Does functional specialization of ribosomes really exist?

It has recently become clear that ribosomes are much more heterogeneous than previously thought, with diversity arising from rRNA sequence and modifications, ribosomal protein (RP) content and posttranslational modifications (PTMs), as well as bound nonribosomal proteins. In some cases, the existence of these diverse ribosome populations has been verified by biochemical or structural methods. Furthermore, knockout or knockdown of RPs can diversify ribosome populations, while also affecting the translation of some mRNAs (but not others) with biological consequences. However, the effects on translation arising from depletion of diverse proteins can be highly similar, suggesting that there may be a more general defect in ribosome function or stability, perhaps arising from reduced ribosome numbers. Consistently, overall reduced ribosome numbers can differentially affect subclasses of mRNAs, necessitating controls for specificity. Moreover, in order to study the functional consequences of ribosome diversity, perturbations including affinity tags and knockouts are introduced, which can also affect the outcome of the experiment. Here we review the available literature to carefully evaluate whether the published data support functional diversification, defined as diverse ribosome populations differentially affecting translation of distinct mRNA (classes). Based on these observations and the commonly observed cellular responses to perturbations in the system, we suggest a set of important controls to validate functional diversity, which should include gain-of-function assays and the demonstration of inducibility under physiological conditions.

Disruption of the Putative Ribosome-Binding Motif of a Scaffold Protein Impairs Cytochrome c Oxidase Subunit Expression in Leishmania major

During their parasitic life cycle, through sandflies and vertebrate hosts, Leishmania parasites confront strikingly different environments, including abrupt changes in pH and temperature, to which they must rapidly adapt. These adaptations include alterations in Leishmania gene expression, metabolism, and morphology, allowing them to thrive as promastigotes in the sandfly and as intracellular amastigotes in the vertebrate host. A critical aspect of Leishmania metabolic adaptation to these changes is maintenance of efficient mitochondrial function in the hostile vertebrate environment. Such functions, including generation of ATP, depend upon the expression of many mitochondrial proteins, including subunits of cytochrome c oxidase (COX). Significantly, under mammalian temperature conditions, expression of Leishmania major COX subunit IV (LmCOX4) and virulence are dependent upon two copies of LACK, a gene that encodes the ribosome-associated scaffold protein, LACK (Leishmania ortholog of RACK1 [receptor for activated C kinase]). Targeted replacement of an endogenous LACK copy with a putative ribosome-binding motif-disrupted variant (LACKR34D35G36→LACKD34D35E36) resulted in thermosensitive parasites that showed diminished LmCOX4 expression, mitochondrial fitness, and replication in macrophages. Surprisingly, despite these phenotypes, LACKD34D35E36 associated with monosomes and polysomes and showed no major impairment of global protein synthesis. Collectively, these data suggest that wild-type (WT) LACK orchestrates robust LmCOX4 expression and mitochondrial fitness to ensure parasite virulence, via optimized functional interactions with the ribosome.IMPORTANCELeishmania parasites are trypanosomatid protozoans that persist in infected human hosts to cause a spectrum of pathologies, from cutaneous and mucocutaneous manifestations to visceral leishmaniasis caused by Leishmania donovani The latter is usually fatal if not treated. Persistence of L. major in the mammalian host depends upon maintaining gene-regulatory programs to support essential parasite metabolic functions. These include expression and assembly of mitochondrial L. major cytochrome c oxidase (LmCOX) subunits, important for Leishmania ATP production. Significantly, under mammalian conditions, WT levels of LmCOX subunits require threshold levels of the Leishmania ribosome-associated scaffold protein, LACK. Unexpectedly, we find that although disruption of LACK's putative ribosome-binding motif does not grossly perturb ribosome association or global protein synthesis, it nonetheless impairs COX subunit expression, mitochondrial function, and virulence. Our data indicate that the quality of LACK's interaction with Leishmania ribosomes is critical for LmCOX subunit expression and parasite mitochondrial function in the mammalian host. Collectively, these findings validate LACK's ribosomal interactions as a potential therapeutic target.

Loss of Ribosomal RACK1 (Receptor for Activated Protein Kinase C 1) Induced by Phosphorylation at T50 Alleviates Cerebral Ischemia-Reperfusion Injury in Rats

Background and Purpose- RACK1 (receptor for activated protein kinase C 1) is an integral component of ribosomes with neuroprotective functions. The goal of this study was to determine the role of RACK1 in cerebral ischemia-reperfusion (I/R) injury and the underlying mechanisms. Methods- A middle cerebral artery occlusion/reperfusion model in adult male Sprague Dawley rats (250-280 g) was established, and cultured neurons were exposed to oxygen-glucose deprivation/reoxygenation to mimic I/R injury in vitro. Expression vectors encoding wild-type RACK1 and RACK1 with T50A mutation (T50A) were constructed and administered to rats by intracerebroventricular injection. Results- The potential role of RACK1 in cerebral I/R injury was confirmed by the decreased protein levels of RACK1 within penumbra tissue, especially of neurons. Second, there was an increase in the phosphorylation ratio of RACK1 at the threonine/serine residues at 1.5 hours after middle cerebral artery occlusion onset. Third, based on site-specific mutagenesis, we identified T50 as a key site for RACK1 phosphorylation during I/R. Fourth, wild-type RACK1 overexpression reduced infarct size, neuronal death, neuronal tissue loss, and neurobehavioral dysfunction, while RACK1 (T50A) overexpression exerted opposite effects. Finally, we found that RACK1 phosphorylation at T50 induced a loss of ribosomal RACK1, which switched RACK1 from beclin-1 translation inhibition to autophagy induction following I/R. Conclusions- RACK1 phosphorylation may be a potential intervention target for neurons during I/R; thus, exogenous supplementation of RACK1 may be a novel approach for ameliorating I/R injury.

Translational Reprogramming Provides a Blueprint for Cellular Adaptation

Consistent with its location on the ribosome, reporter assays demonstrate a role for Rps26 in recognition of the Kozak sequence. Consequently, Rps26-deficient ribosomes display preference for mRNAs encoding components of the high salt and high pH stress response pathways and accumulate in yeast exposed to high salt or pH. Here we use this information to reprogram the cellular response to high salt by introducing point mutations in the Kozak sequence of key regulators for the cell wall MAP-kinase, filamentation, or DNA repair pathways. This stimulates their translation upon genetic, or salt-induced Rps26 depletion from ribosomes. Stress resistance assays show activation of the targeted pathways in an Rps26- and salt-dependent manner. Genomic alterations in diverse yeast populations indicate that analogous tuning occurs during adaptation to ecological niches. Thus, evolution shapes translational control across the genome by taking advantage of the accumulation of diverse ribosome populations.

eIF5A is required for autophagy by mediating ATG3 translation

Autophagy is an essential catabolic process responsible for recycling of intracellular material and preserving cellular fidelity. Key to the autophagy pathway is the ubiquitin-like conjugation system mediating lipidation of Atg8 proteins and their anchoring to autophagosomal membranes. While regulation of autophagy has been characterized at the level of transcription, protein interactions and post-translational modifications, its translational regulation remains elusive. Here we describe a role for the conserved eukaryotic translation initiation factor 5A (eIF5A) in autophagy. Identified from a high-throughput screen, we find that eIF5A is required for lipidation of LC3B and its paralogs and promotes autophagosome formation. This feature is evolutionarily conserved and results from the translation of the E2-like ATG3 protein. Mechanistically, we identify an amino acid motif in ATG3 causing eIF5A dependency for its efficient translation. Our study identifies eIF5A as a key requirement for autophagosome formation and demonstrates the importance of translation in mediating efficient autophagy.