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Autophagy Sep 2019Based on my reading, and on my own experience, I have come to realize that people learn in different ways, and this can include the use of different media. This is one...
Based on my reading, and on my own experience, I have come to realize that people learn in different ways, and this can include the use of different media. This is one reason I have worked with various artists to portray the topic of autophagy through paintings, music and dance. Indeed, comments from members of the audience who have attended one of my seminars often suggest that a particular artistic approach 'hit home' and added meaning to them about the topic. In this issue of the journal I describe another such project-'the-found-art vacuole'-that utilized the talents of an amazing watercolor painter, Scott Hartley. The object of Scott's painting is the only artophagy composition that I have 'made'-assembled is a more accurate word. Doing so was quite fun, but after examining many of the 'antique' items that form the 'found-art vacuole', I realized that it would be nice to have a painting that was done in exquisite detail. The requirement for detail immediately made me think of Scott, whose work I was familiar with from the Ann Arbor Art Fair. To quote a line from the Belleville News-Democrat describing Scott's taking first place in an art competition, 'He began by doing landscapes, and eventually found a different style for his work: the intricacies of urban architecture, of alleys and fire escapes in a city neighborhood.' This does describe the nature of Scott's work, but you have to see these paintings to appreciate the detail.
Topics: Autophagy; Music; Paintings; Saccharomyces cerevisiae; Vacuoles
PubMed: 31238790
DOI: 10.1080/15548627.2019.1630225 -
Nature Communications Jan 2023A variety of intracellular bacteria modulate the host cytoskeleton to establish subcellular niches for replication. However, the role of intermediate filaments, which...
A variety of intracellular bacteria modulate the host cytoskeleton to establish subcellular niches for replication. However, the role of intermediate filaments, which are crucial for mechanical strength and resilience of the cell, and in bacterial vacuole preservation remains unclear. Here, we show that Salmonella effector SopB reorganizes the vimentin network to form cage-like structures that surround Salmonella-containing vacuoles (SCVs). Genetic removal of vimentin markedly disrupts SCV organization, significantly reduces bacterial replication and cell death. Mechanistically, SopB uses its N-terminal Cdc42-binding domain to interact with and activate Cdc42 GTPase, which in turn recruits vimentin around SCVs. A high-content imaging-based screening identified that MEK1/2 inhibition led to vimentin dispersion. Our work therefore elucidates the signaling axis SopB-Cdc42-MEK1/2 as mobilizing host vimentin to maintain concrete SCVs and identifies a mechanism contributing to Salmonella replication. Importantly, Trametinib, a clinically-approved MEK1/2 inhibitor identified in the screen, displayed significant anti-infection efficacy against Salmonella both in vitro and in vivo, and may provide a therapeutic option for treating drug-tolerant salmonellosis.
Topics: Humans; Bacterial Proteins; Cytoskeleton; Intermediate Filaments; Salmonella typhimurium; Vacuoles; Vimentin; Animals
PubMed: 36717589
DOI: 10.1038/s41467-023-36123-w -
Cellular Microbiology Oct 2020Intracellular bacterial pathogens harbour genes, the closest homologues of which are found in eukaryotes. Regulator of chromosome condensation 1 (RCC1) repeat proteins... (Review)
Review
Intracellular bacterial pathogens harbour genes, the closest homologues of which are found in eukaryotes. Regulator of chromosome condensation 1 (RCC1) repeat proteins are phylogenetically widespread and implicated in protein-protein interactions, such as the activation of the small GTPase Ran by its cognate guanine nucleotide exchange factor, RCC1. Legionella pneumophila and Coxiella burnetii, the causative agents of Legionnaires' disease and Q fever, respectively, harbour RCC1 repeat coding genes. Legionella pneumophila secretes the RCC1 repeat 'effector' proteins LegG1, PpgA and PieG into eukaryotic host cells, where they promote the activation of the pleiotropic small GTPase Ran, microtubule stabilisation, pathogen vacuole motility and intracellular bacterial growth as well as host cell migration. The RCC1 repeat effectors localise to the pathogen vacuole or the host plasma membrane and target distinct components of the Ran GTPase cycle, including Ran modulators and the small GTPase itself. Coxiella burnetii translocates the RCC1 repeat effector NopA into host cells, where the protein localises to nucleoli. NopA binds to Ran GTPase and promotes the nuclear accumulation of Ran(GTP), thus pertubing the import of the transcription factor NF-κB and innate immune signalling. Hence, divergent evolution of bacterial RCC1 repeat effectors defines the range of Ran GTPase cycle targets and likely allows fine-tuning of Ran GTPase activation by the pathogens at different cellular sites.
Topics: Animals; Bacterial Proteins; Biological Evolution; Cell Nucleolus; Coxiella burnetii; Enzyme Activation; Genes, Bacterial; Guanine Nucleotide Exchange Factors; Host-Pathogen Interactions; Humans; Legionella; Legionella pneumophila; Legionnaires' Disease; Protein Transport; Q Fever; Vacuoles; ran GTP-Binding Protein
PubMed: 32720355
DOI: 10.1111/cmi.13246 -
Biochimica Et Biophysica Acta.... Dec 2020Vacuole is a prominent organelle that often occupies most of the plant cell volume. The vacuolar accumulation of secondary metabolites, also called specialized... (Review)
Review
Vacuole is a prominent organelle that often occupies most of the plant cell volume. The vacuolar accumulation of secondary metabolites, also called specialized metabolites, plays important roles in environmental responses such as protecting against insect herbivores and attracting pollinators. The compartmentation of xenobiotics in the vacuole is also essential for adaptation to environmental stresses. These accumulations involve several transport systems, for which some responsible transporter proteins have been reported. Furthermore, studies on biosynthetic enzymes and transporters of secondary metabolites have revealed that vacuoles, which have been recognized for many years as a site for accumulation, also function as a site for biosynthesis of secondary metabolites and are thus actively involved in the entire biosynthetic process. In this review, we briefly summarize recent findings on vacuolar transporters involved in secondary metabolites and xenobiotics, and discuss their roles in plant adaptation to biotic and abiotic stresses, through vacuolar dynamism.
Topics: Alkaloids; Anthocyanins; Biological Transport; Multidrug Resistance-Associated Proteins; Organic Cation Transport Proteins; Phenols; Plant Proteins; Plants; Vacuoles; Xenobiotics
PubMed: 31738903
DOI: 10.1016/j.bbamem.2019.183127 -
Cells Jun 2022Cells rely on autophagy to degrade cytosolic material and maintain homeostasis. During autophagy, content to be degraded is encapsulated in double membrane vesicles,... (Review)
Review
Cells rely on autophagy to degrade cytosolic material and maintain homeostasis. During autophagy, content to be degraded is encapsulated in double membrane vesicles, termed autophagosomes, which fuse with the yeast vacuole for degradation. This conserved cellular process requires the dynamic rearrangement of membranes. As such, the process of autophagy requires many soluble proteins that bind to membranes to restructure, tether, or facilitate lipid transfer between membranes. Here, we review the methods that have been used to investigate membrane binding by the core autophagy machinery and additional accessory proteins involved in autophagy in yeast. We also review the key experiments demonstrating how each autophagy protein was shown to interact with membranes.
Topics: Autophagosomes; Autophagy; Proteins; Saccharomyces cerevisiae; Vacuoles
PubMed: 35741004
DOI: 10.3390/cells11121876 -
Cells Aug 2022Recent studies have highlighted the importance of autophagy and particularly non-canonical autophagy in the development and progression of acute pancreatitis (a frequent... (Review)
Review
Recent studies have highlighted the importance of autophagy and particularly non-canonical autophagy in the development and progression of acute pancreatitis (a frequent disease with considerable morbidity and significant mortality). An important early event in the development of acute pancreatitis is the intrapancreatic activation of trypsinogen, (i.e., formation of trypsin) leading to the autodigestion of the organ. Another prominent phenomenon associated with the initiation of this disease is vacuolisation and specifically the formation of giant endocytic vacuoles in pancreatic acinar cells. These organelles develop in acinar cells exposed to several inducers of acute pancreatitis (including taurolithocholic acid and high concentrations of secretagogues cholecystokinin and acetylcholine). Notably, early trypsinogen activation occurs in the endocytic vacuoles. These trypsinogen-activating organelles undergo activation, long-distance trafficking, and non-canonical autophagy. In this review, we will discuss the role of autophagy in acute pancreatitis and particularly focus on the recently discovered LAP-like non-canonical autophagy (LNCA) of endocytic vacuoles.
Topics: Acute Disease; Autophagy; Humans; Pancreatitis; Trypsinogen; Vacuoles
PubMed: 36010591
DOI: 10.3390/cells11162514 -
FEBS Letters Sep 2022Seed storage proteins (SSPs) accumulated within plant seeds constitute the major protein nutrition sources for human and livestock. SSPs are synthesized on the... (Review)
Review
Seed storage proteins (SSPs) accumulated within plant seeds constitute the major protein nutrition sources for human and livestock. SSPs are synthesized on the endoplasmic reticulum and are then deposited in plant-specific protein bodies, including endoplasmic reticulum-derived protein bodies and protein storage vacuoles. Plant seeds have evolved a distinct endomembrane system to accomplish SSP transport. There are two distinct types of trafficking pathways contributing to SSP delivery to protein storage vacuoles: one is Golgi-dependent and the other is Golgi-independent. In recent years, molecular, genetic, and biochemical studies have shed light on the complex network controlling SSP trafficking, to which both evolutionarily conserved molecular machineries and plant-unique regulators contribute. In this review, we discuss current knowledge of protein body biogenesis and endomembrane-mediated SSP transport, focusing on endoplasmic reticulum export and post-Golgi traffic. This knowledge supports a dominant role for the Golgi-dependent pathways in SSP transport in Arabidopsis and rice. In addition, we describe cutting-edge strategies for dissecting the endomembrane trafficking system in plant seeds to advance the field.
Topics: Arabidopsis; Golgi Apparatus; Plant Proteins; Plants; Protein Transport; Seed Storage Proteins; Seeds; Vacuoles
PubMed: 35615915
DOI: 10.1002/1873-3468.14374 -
The Journal of Biological Chemistry Feb 2020Lysine polyphosphorylation (K-PPn) is a relatively new post-translational modification, the full targets and functional consequences of which are unknown. A critical...
Lysine polyphosphorylation (K-PPn) is a relatively new post-translational modification, the full targets and functional consequences of which are unknown. A critical problem in the study of endogenous K-PPn of proteins in the yeast model system is that its nonenzymatic nature and its susceptibility to polyphosphatases make it potentially susceptible to artifacts during extraction. A new study confirms that K-PPn modifications can be altered during sample handling, provides new insights into the mechanism of K-PPn, and develops a yeast model strain, devoid of both vacuolar polyP and polyphosphatases, that allows detection of authentic endogenous K-PPn.
Topics: Lysine; Phosphorylation; Polyphosphates; Protein Processing, Post-Translational; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Vacuoles
PubMed: 32034011
DOI: 10.1074/jbc.H120.012632 -
International Journal of Molecular... Mar 2020Autophagy is an evolutionarily conserved process that occurs in yeast, plants, and animals. Despite many years of research, some aspects of autophagy are still not fully... (Review)
Review
Autophagy is an evolutionarily conserved process that occurs in yeast, plants, and animals. Despite many years of research, some aspects of autophagy are still not fully explained. This mostly concerns the final stages of autophagy, which have not received as much interest from the scientific community as the initial stages of this process. The final stages of autophagy that we take into consideration in this review include the formation and degradation of the autophagic bodies as well as the efflux of metabolites from the vacuole to the cytoplasm. The autophagic bodies are formed through the fusion of an autophagosome and vacuole during macroautophagy and by vacuolar membrane invagination or protrusion during microautophagy. Then they are rapidly degraded by vacuolar lytic enzymes, and products of the degradation are reused. In this paper, we summarize the available information on the trafficking of the autophagosome towards the vacuole, the fusion of the autophagosome with the vacuole, the formation and decomposition of autophagic bodies inside the vacuole, and the efflux of metabolites to the cytoplasm. Special attention is given to the formation and degradation of autophagic bodies and metabolite salvage in plant cells.
Topics: Autophagosomes; Autophagy; Biological Transport; Cytoplasm; Phagosomes; Plant Physiological Phenomena; Proteolysis; Vacuoles
PubMed: 32210003
DOI: 10.3390/ijms21062205 -
Proceedings of the National Academy of... May 2023Vac8, a yeast vacuolar protein with armadillo repeats, mediates various cellular processes by changing its binding partners; however, the mechanism by which Vac8...
Vac8, a yeast vacuolar protein with armadillo repeats, mediates various cellular processes by changing its binding partners; however, the mechanism by which Vac8 differentially regulates these processes remains poorly understood. Vac8 interacts with Nvj1 to form the nuclear-vacuole junction (NVJ) and with Atg13 to mediate cytoplasm-to-vacuole targeting (Cvt), a selective autophagy-like pathway that delivers cytoplasmic aminopeptidase I directly to the vacuole. In addition, Vac8 associates with Myo2, a yeast class V myosin, through its interaction with Vac17 for vacuolar inheritance from the mother cell to the emerging daughter cell during cell divisions. Here, we determined the X-ray crystal structure of the Vac8-Vac17 complex and found that its interaction interfaces are bipartite, unlike those of the Vac8-Nvj1 and Vac8-Atg13 complexes. When the key amino acids present in the interface between Vac8 and Vac17 were mutated, vacuole inheritance was severely impaired in vivo. Furthermore, binding of Vac17 to Vac8 prevented dimerization of Vac8, which is required for its interactions with Nvj1 and Atg13, by clamping the H1 helix to the ARM1 domain of Vac8 and thereby preventing exposure of the binding interface for Vac8 dimerization. Consistently, the binding affinity of Vac17-bound Vac8 for Nvj1 or Atg13 was markedly lower than that of free Vac8. Likewise, free Vac17 had no affinity for the Vac8-Nvj1 and Vac8-Atg13 complexes. These results provide insights into how vacuole inheritance and other Vac8-mediated processes, such as NVJ formation and Cvt, occur independently of one another.
Topics: Saccharomyces cerevisiae; Vesicular Transport Proteins; Saccharomyces cerevisiae Proteins; Vacuoles; Cytoplasm; Protein Transport; Autophagy; Autophagy-Related Proteins; Adaptor Proteins, Signal Transducing; Receptors, Cell Surface
PubMed: 37094131
DOI: 10.1073/pnas.2211501120