CVClient

桜井 一

サクライ ハジメ  (Hajime Sakurai)

基本情報

所属
兵庫県立大学 理学研究科 生体物質化学Ⅱ講座 助教
学位
博士(理学)(2016年9月 東京大学)

研究者番号
00796732
J-GLOBAL ID
201801005677937742
researchmap会員ID
7000025498

研究キーワード

 1

主要な論文

 14
  • Hajime Tajima Sakurai, Satoko Arakawa, Hirofumi Yamaguchi, Satoru Torii, Shinya Honda, Shigeomi Shimizu
    Cells 12(24) 2817-2817 2023年12月11日  査読有り筆頭著者
    Autophagy is a cellular mechanism that utilizes lysosomes to degrade its own components and is performed using Atg5 and other molecules originating from the endoplasmic reticulum membrane. On the other hand, we identified an alternative type of autophagy, namely, Golgi membrane-associated degradation (GOMED), which also utilizes lysosomes to degrade its own components, but does not use Atg5 originating from the Golgi membranes. The GOMED pathway involves Ulk1, Wipi3, Rab9, and other molecules, and plays crucial roles in a wide range of biological phenomena, such as the regulation of insulin secretion and neuronal maintenance. We here describe the overview of GOMED, methods to detect autophagy and GOMED, and to distinguish GOMED from autophagy.
  • Hajime Tajima Sakurai, Hidefumi Iwashita, Satoko Arakawa, Alifu Yikelamu, Mizuki Kusaba, Satoshi Kofuji, Hiroshi Nishina, Munetaka Ishiyama, Yuichiro Ueno, Shigeomi Shimizu
    iScience 26(7) 107218-107218 2023年7月  査読有り筆頭著者
  • Hajime Tajima Sakurai, Satoko Arakawa, Saori Noguchi, Shigeomi Shimizu
    Scientific Reports 12(1) 2022年12月27日  査読有り筆頭著者
    Abstract Autophagy results in the degradation of cytosolic components via two major membrane deformations. First, the isolation membrane sequesters components from the cytosol and forms autophagosomes, by which open structures become closed compartments. Second, the outer membrane of the autophagosomes fuses with lysosomes to degrade the inner membrane and its contents. The efficiency of the latter degradation process, namely autophagic flux, can be easily evaluated using lysosomal inhibitors, whereas the dynamics of the former process is difficult to analyze because of the challenges in identifying closed compartments of autophagy (autophagosomes and autolysosomes). To resolve this problem, we here developed a method to detect closed autophagic compartments by applying the FLIP technique, and named it FLIP-based Autophagy Detection (FLAD). This technique visualizes closed autophagic compartments and enables differentiation of open autophagic structures and closed autophagic compartments in live cells. In addition, FLAD analysis detects not only starvation-induced canonical autophagy but also genotoxic stress-induced alternative autophagy. By the combinational use of FLAD and LC3, we were able to distinguish the structures of canonical autophagy from those of alternative autophagy in a single cell.
  • Hidefumi Iwashita, Hajime Tajima Sakurai, Noriyoshi Nagahora, Munetaka Ishiyama, Kosei Shioji, Kazumi Sasamoto, Kentaro Okuma, Shigeomi Shimizu, Yuichiro Ueno
    FEBS Letters 592(4) 559-567 2018年2月1日  査読有り
    We have developed two types of fluorescent probes, DALGreen and DAPGreen, for monitoring autophagy, that exhibit fluorescence upon being incorporated into autophagosomes. DALGreen enhances its fluorescence at acidic pH, which is favorable for monitoring late-phase autophagy, whereas DAPGreen remains fluorescent with almost constant brightness during the autophagic process. With these probes that stain autophagosomes as they are being formed, the real-time change of autophagic phenomena of live cells may be traced, which is an advantage over conventional approaches with small molecules that stain mature autophagosomes. The use of both dyes allows monitoring of the membrane dynamics of autophagy in any type of cell without the need for genetic engineering, and therefore, will be useful as a tool to study autophagic phenomena.
  • Hajime Tajima Sakurai, Takeshi Inoue, Akihiko Nakano, Takashi Ueda
    PLANT CELL 28(6) 1490-1503 2016年6月  査読有り筆頭著者
    RAB5 GTPases act as molecular switches that regulate various endosomal functions in animal cells, including homotypic fusion of early endosomes, endosomal motility, endosomal signaling, and subcompartmentalization of the endosomal membrane. RAB5 proteins fulfill these diverse functions through interactions with downstream effector molecules. Two canonical RAB5 members, ARA7 and RAB HOMOLOG1 (RHA1), are encoded in the Arabidopsis thaliana genome. ARA7 and RHA1 play crucial roles in endocytic and vacuolar trafficking pathways. Plant RAB5 GTPases function via interactions with effector molecules, whose identities and functions are currently unclear. In this study, we searched for canonical RAB5 effector molecules of Arabidopsis and identified a candidate, which we called ENDOSOMAL RAB EFFECTOR WITH PX-DOMAIN (EREX). The intimate genetic interaction between EREX and RAB5 members, the results from subcellular colocalization experiments, and the direct interaction observed in an in vitro pull-down assay strongly suggest that EREX is a genuine effector of canonical RAB5s in Arabidopsis. We further found that close homologs of EREX play partially redundant functions with EREX in the transport of seed storage proteins. Our results indicate that canonical plant RAB5s acquired distinct effector molecules from those of non-plant systems to fulfill their functions.

MISC

 5

講演・口頭発表等

 30

所属学協会

 2

共同研究・競争的資金等の研究課題

 7

社会貢献活動

 3

主要なメディア報道

 2