Hayashi Yamamoto

During the process of autophagy, cytoplasmic materials are sequestered by double-membrane structures, the autophagosomes, and then transported to a lytic compartment to be degraded. One of the most fundamental questions about autophagy involves the origin of the autophagosomal membranes. In this study, we focus on the intracellular dynamics of Atg9, a multispanning membrane protein essential for autophagosome formation in yeast. We found that the vast majority of Atg9 existed on cytoplasmic mobi

Mitochondria import most of their resident proteins from the cytosol, and the import receptor Tom20 of the outer-membrane translocator TOM40 complex plays an essential role in specificity of mitochondrial protein import. Here we analyzed the effects of Tom20 binding on NMR spectra of a long mitochondrial presequence and found that it contains two distinct Tom20-binding elements. In vitro import and cross-linking experiments revealed that, although the N-terminal Tom20-binding element is essentia

Mitochondrial protein traffic requires precise recognition of the mitochondrial targeting signals by the import receptors on the mitochondrial surface including a general import receptor Tom20 and a receptor for presequence-less proteins, Tom70. Here we took a proteome-wide approach of mitochondrial protein import in vitro to find a set of presequence-containing precursor proteins for recognition by Tom70. The presequences of the Tom70-dependent precursor proteins were recognized by Tom20, where

Autophagy is a self-digestive process that is conserved in eukaryotic cells and responsible for maintaining cellular homeostasis through proteolysis. By this process, cells break down their own components in lysosomes. Autophagy can be classified into three categories: macroautophagy, microautophagy, and chaperone-mediated autophagy (CMA). Macroautophagy involves membrane elongation and microautophagy involves membrane internalization, and both pathways undergo selective or non-selective process

Here, we report the identification of yeast 15-kD Tim15/Zim17, a new member of mitochondrial Hsp70 (mtHsp70)-associated motor and chaperone (MMC) proteins. The 15-kD MMC protein is a peripheral inner membrane protein with a zinc-finger motif. Depletion of the 15-kD protein led to impaired import of presequence-containing proteins into the matrix in vivo and in vitro. Overexpression of the 15-kD protein rescued the functional defects of mtHsp70 in ssc1-3 cells, and a fusion protein containing the

Autophagy is a conserved degradation process in which autophagosomes are generated by cooperative actions of multiple autophagy-related (Atg) proteins. Previous studies using the model yeast Saccharomyces cerevisiae have provided various insights into the molecular basis of autophagy; however, because of the modest stability of several Atg proteins, structural and biochemical studies have been limited to a subset of Atg proteins, preventing us from understanding how multiple Atg proteins functio

Abstract Macroautophagy is a cellular process that delivers cytoplasmic material to lysosomes for degradation via autophagosomes. It often involves the selective degradation of ubiquitinated proteins. During selective macroautophagy, five ubiquitin-binding adaptors, p62, NBR1, OPTN, NDP52, and TAX1BP1, form biomolecular condensates with ubiquitinated proteins and recruit ATG9 vesicles, which serve as the initial membrane source required for autophagosome formation. However, the molecular details

A large-scale distributed system is constructed step by step over a long period of time. Even under construction, online operation is started in its system. After starting online operation, it continuously has to be tested and maintained in various areas without stopping online operation. In the conventional online test technique for an autonomous decentralized system, the online and the test data exist concurrently in the same system. The real-time response of the online system is not assured.

Abstract Monitoring autophagic flux is necessary for most autophagy studies. The autophagic flux assays currently available for mammalian cells are generally complicated and do not yield highly quantitative results. Yeast autophagic flux is routinely monitored with the GFP-based processing assay, whereby the amount of GFP proteolytically released from GFP-containing reporters (e.g., GFP-Atg8), detected by immunoblotting, reflects autophagic flux. However, this simple and effective assay is typic

We propose a technique for combining devices to create a more flexible context-aware service system. This system integrates devices that are embedded or distributed in the user's environment and are networked with each other. The system for providing context-aware services locates and selects devices appropriate to the user's context. When the context changes while the service is being provided, devices for that service can be partially reconfigured without resetting all the parameters. We have