The Atg8 conjugation system is indispensable for proper development of autophagic isolation membranes in mice.

Autophagy is an evolutionarily conserved bulk-protein degradation pathway in which isolation membranes engulf the cytoplasmic constituents, and the resulting autophagosomes transport them to lysosomes. Two ubiquitin-like conjugation systems, termed Atg12 and Atg8 systems, are essential for autophagosomal formation. In addition to the pathophysiological roles of autophagy in mammals, recent mouse genetic studies have shown that the Atg8 system is predominantly under the control of the Atg12 system.

Structural basis for sorting mechanism of p62 in selective autophagy.

Impairment of autophagic degradation of the ubiquitin- and LC3-binding protein "p62" leads to the formation of cytoplasmic inclusion bodies. However, little is known about the sorting mechanism of p62 to autophagic degradation. Here we identified a motif of murine p62 consisting of 11 amino acids (Ser334-Ser344) containing conserved acidic and hydrophobic residues across species, as an LC3 recognition sequence (LRS).

Loss of Pten, a tumor suppressor, causes the strong inhibition of autophagy without affecting LC3 lipidation.

(1)Pten (phosphatase and tensin homolog deleted on chromosome ten), a tumor suppressor, is a phosphatase with a variety of substrate specificities. Its function as a negative regulator of the class I phosphatidyl-inositol 3-kinase/Akt pathway antagonizes insulin-dependent cell signaling. The targeted deletion of Pten in mouse liver leads to insulin hypersensitivity and the upregulation of the phosphatidyl-inositol 3-kinase/Akt signaling pathway.

Comprehensive proteomics analysis of autophagy-deficient mouse liver.

Autophagy is a bulk protein degradation system for the entire organelles and cytoplasmic proteins. Previously, we have shown the liver dysfunction by autophagy deficiency. To examine the pathological effect of autophagy deficiency, we examined protein composition and their levels in autophagy-deficient liver by the proteomic analysis.

Guidelines for the use and interpretation of assays for monitoring autophagy in higher eukaryotes.

Research in autophagy continues to accelerate,(1) and as a result many new scientists are entering the field. Accordingly, it is important to establish a standard set of criteria for monitoring macroautophagy in different organisms. Recent reviews have described the range of assays that have been used for this purpose.

Inhibition of autophagy prevents hippocampal pyramidal neuron death after hypoxic-ischemic injury.

Neonatal hypoxic/ischemic (H/I) brain injury causes neurological impairment, including cognitive and motor dysfunction as well as seizures. However, the molecular mechanisms regulating neuron death after H/I injury are poorly defined and remain controversial. Here we show that Atg7, a gene essential for autophagy induction, is a critical mediator of H/I-induced neuron death.

Toll-like receptor signalling in macrophages links the autophagy pathway to phagocytosis.

Phagocytosis and autophagy are two ancient, highly conserved processes involved, respectively, in the removal of extracellular organisms and the destruction of organisms in the cytosol. Autophagy, for either metabolic regulation or defence, involves the formation of a double membrane called the autophagosome, which then fuses with lysosomes to degrade the contents, a process that has similarities with phagosome maturation. Toll-like-receptor (TLR) engagement activates a variety of defence mechanisms within phagocytes, including facilitation of phagosome maturation, and also engages autophagy.

Neuronal autophagy: going the distance to the axon.

Autophagy, a regulated cellular degradation process responsible for the turnover of long-lived proteins and organelles, has been increasingly implicated in neurological disorders. Although autophagy is mostly viewed as a stress-induced process, recent studies have indicated that it is constitutively active in central nervous system (CNS) neurons and is protective against neurodegeneration. Neurons are highly specialized, post-mitotic cells that are typically composed of a soma (cell body), a dendritic tree and an axon.

UFT and its metabolite gamma-butyrolactone (GBL) inhibit angiogenesis induced by vascular endothelial growth factor in advanced cervical carcinoma.

Objective: The aim of this study was to evaluate the potential role of UFT and its metabolite gamma-butyrolactone (GBL) for inhibition of angiogenesis induced by vascular endothelial growth factor (VEGF) in advanced cervical carcinoma by the determination of serum GBL and VEGF, and by immunohistochemical staining to assess VEGF protein expression, before and after UFT therapy.

Methods: The subjects were 35 patients with an advanced cervical carcinoma and five healthy volunteers between 2002 and 2003 at Hiroshima University Hospital, under informed consent. The patients received two courses of oral fluoropyrimidine (UFT) therapy at a dose of 600 mg/day for 5 and 2 days off treatment.

Crystal structure of Ufc1, the Ufm1-conjugating enzyme.

Ubiquitin and ubiquitin-like protein-conjugating enzymes play central roles in posttranslational modification processes. The ubiquitin-fold modifier 1 (Ufm1), one of a variety of ubiquitin-like modifiers, is covalently attached to target proteins via Uba5 and Ufm1-conjugating enzyme 1 (Ufc1), which are analogous to the E1 and E2 ubiquitylation enzymes. As Ufm1-related proteins are conserved in metazoa and plants, the Ufm1 system likely plays important roles in various multicellular organisms.

Essential role for autophagy protein Atg7 in the maintenance of axonal homeostasis and the prevention of axonal degeneration.

Autophagy is a regulated lysosomal degradation process that involves autophagosome formation and transport. Although recent evidence indicates that basal levels of autophagy protect against neurodegeneration, the exact mechanism whereby this occurs is not known. By using conditional knockout mutant mice, we report that neuronal autophagy is particularly important for the maintenance of local homeostasis of axon terminals and protection against axonal degeneration.

Two novel ubiquitin-fold modifier 1 (Ufm1)-specific proteases, UfSP1 and UfSP2.

Ubiquitin-fold modifier 1 (Ufm1) is a recently identified new ubiquitin-like protein, whose tertiary structure displays a striking resemblance to ubiquitin. Similar to ubiquitin, it has a Gly residue conserved across species at the C-terminal region with extensions of various amino acid sequences that need to be processed in vivo prior to conjugation to target proteins. Here we report the isolation, cloning, and characterization of two novel mouse Ufm1-specific proteases, named UfSP1 and UfSP2.

Autophagy and neurodegeneration.

The proteasome and lysosome are sophisticated apparatuses capable of shredding unnecessary proteins in eukaryotic cells. The proteasome and its partner ubiquitin (which functions as a destination signal for proteolysis) play crucial roles in selective breakdown of not only short-lived regulatory proteins but also abnormal proteins that need to be rapidly eliminated from the cells. It is generally accepted that deficits of the proteasome-ubiquitin system are associated with various neurodegenerative diseases, since ubiquitin-positive inclusions frequently appear in neurons of patients and mice models of neurodegenerative diseases.

[Autophagic-lysosomal system: physiology and pathology].

There is increased evidence for the importance of autophagy as a membrane trafficking mechanism that delivers cytoplasmic constituents into the lysosome/vacuole for bulk protein degradation. In this review, we introduce the in vivo role of autophagy in mammals. Recently, we generated conditional-knockout mice of Atg7, an essential gene for autophagy in yeast.

Prediction of individual response to platinum/paclitaxel combination using novel marker genes in ovarian cancers.

We attempted to identify potent marker genes using a new statistical analysis and developed a prediction system for individual response to platinum/paclitaxel combination chemotherapy in ovarian cancer patients based on the hypothesis that expression analysis of a set of the key drug sensitivity genes for platinum and paclitaxel could allow us to predict therapeutic response to the combination. From 10 human ovarian cancer cell lines, genes correlative in the expression levels with cytotoxicities of cisplatin (CDDP) and paclitaxel were chosen. We first selected five reliable prediction markers for the two drugs from 22 genes already known as sensitivity determinants and then identified another 8 novel genes through a two-dimensional mixed normal model using oligomicroarray expression data.

Solution structure and dynamics of Ufm1, a ubiquitin-fold modifier 1.

The ubiquitin-fold modifier 1 (Ufm1) is one of various ubiquitin-like modifiers and conjugates to target proteins in cells through Uba5 (E1) and Ufc1 (E2). The Ufm1-system is conserved in metazoa and plants, suggesting its potential roles in various multicellular organisms. Herein, we analyzed the solution structure and dynamics of human Ufm1 (hsUfm1) by nuclear magnetic resonance spectroscopy.

Excess peroxisomes are degraded by autophagic machinery in mammals.

Peroxisomes are degraded by autophagic machinery termed "pexophagy" in yeast; however, whether this is essential for peroxisome degradation in mammals remains unknown. Here we have shown that Atg7, an essential gene for autophagy, plays a pivotal role in the degradation of excess peroxisomes in mammals. Following induction of peroxisomes by a 2-week treatment with phthalate esters in control and Atg7-deficient livers, peroxisomal degradation was monitored within 1 week after discontinuation of phthalate esters.

The crystal structure of human Atg4b, a processing and de-conjugating enzyme for autophagosome-forming modifiers.

Autophagy is an evolutionarily conserved pathway in which the cytoplasm and organelles are engulfed within double-membrane vesicles, termed autophagosomes, for the turnover and recycling of these cellular constituents. The yeast Atg8 and its human orthologs, such as LC3 and GABARAP, have a unique feature as they conjugate covalently to phospholipids, differing from ubiquitin and other ubiquitin-like modifiers that attach only to protein substrates. The lipidated Atg8 and LC3 localize to autophagosomal membranes and play indispensable roles for maturation of autophagosomes.

Phosphatidylserine in addition to phosphatidylethanolamine is an in vitro target of the mammalian Atg8 modifiers, LC3, GABARAP, and GATE-16.

In yeast, phosphatidylethanolamine is a target of the Atg8 modifier in ubiquitylation-like reactions essential for autophagy. Three human Atg8 (hAtg8) homologs, LC3, GABARAP, and GATE-16, have been characterized as modifiers in reactions mediated by hAtg7 (an E1-like enzyme) and hAtg3 (an E2-like enzyme) as in yeast Atg8 lipidation, but their final targets have not been identified. The results of a recent study in which COS7 cells were incubated with [14C]ethanolamine for 48 h suggested that phosphatidylethanolamine is a target of LC3.