FY2018 Annual Report

Membranology Unit
Assistant Professor Keiko Kono

 

Abstract

FY2018 was our first year at OIST. We welcomed one postdoc, one technitian, one Ph.D. student, two rotation students and one intern student. Fortunately, we could celebrate our first publication at OIST.  We have multiple projects ready to bloom. 

1. Staff

  • Dr. Yohsuke Moriyama, Science and Technology Associate
  • Dr. Yumiko Masukagami, Postdoc
  • Ms. Yuri Matsui, Technician
  • Mr. Hunter Barbee, PhD Student
  • Ms. Aisulu Maipas, Rotation Student
  • Mr. Christopher Zhu, Research Intern
  • Ms. Hitomi Ohtaki, Research Unit Administrator

2. Collaborations

2.1 Cellular Wound Healing during Beer Brewing

  • Type of collaboration: Joint research
  • Researchers:
    • Dr. Yukiko Kodama, Suntory Global Innovation Center
    • Dr. Nozomu Kamada, Suntory Global Innovation Center
    • Dr. Fumihiko Omura, Suntory Global Innovation Center

2.2 Mitotic Cell Rounding

  • Type of collaboration: Joint research
  • Researchers:
    • Professor Makoto Nakanishi, The University of Tokyo, The Institute of Medical Science
    • Dr. Toru Hirota, Cancer Institute of the Japanese Foundation for Cancer Research
    • Professor Shige H. Yoshimura, Kyoto University

2.3 Mechanisms and Consequences of Plasma Membrane Damage

  • Type of collaboration: Joint research
  • Researchers:
    • Professor Mamiko Yajima, Brown University

3. Activities and Findings

The mechanism enabling the smooth cell division in human cells

Animal cells, including human cells, undergo rapid rounding during mitosis (Fig 1), ensuring proper chromosome segregation. During this process, an outward rounding force increases upon prometaphase entry and is maintained at a constant level during metaphase. The cortical tension is generated by myosin motors and filamentous actin. However, the molecular mechanisms and physiological consequences of metaphase cortical tension maintenance remain unknown. We demonstrate that Cdk1-mediated phosphorylation of DIAPH1 stably maintains cortical tension after rounding and inactivates the spindle assembly checkpoint (SAC). Cdk1 phosphorylates DIAPH1, preventing profilin1 binding to maintain cortical tension. Mutation of DIAPH1 phosphorylation sites promotes cortical F-actin accumulation, increases cortical tension, and delays anaphase onset due to SAC activation. Measurement of the intra-kinetochore length suggests that Cdk1-mediated cortex relaxation is indispensable for kinetochore stretching. We thus uncovered a previously unknown mechanism by which Cdk1 coordinates cortical tension maintenance and SAC inactivation at anaphase onset. These results are published in Nature Communications.

 

Figure 1: Mitotic cell rounding of a HeLa cell. Green: GFP-LifeAct (F-Actin), Red: mCherry-H2B (Chromosome).

 

 

 

4. Publications

4.1 Journals

  1. Nishimura K, Johmura Y, Deguchi K, Jiang Z, Uchida KSK, Suzuki N, Shimada M, Chiba Y, Hirota T, Yoshimura SH, Kono K, and Nakanishi M. Cdk1-mediated DIAPH1 phosphorylation maintains metaphase cortical tension and inactivates the spindle assembly checkpoint at anaphase. Nature Commun. Co-corresponding Author.   https://rdcu.be/bo1jC 

4.2 Books and other one-time publications

Nothing to report

4.3 Oral and Poster Presentations

Oral Presentation (Invited lectures only)

  1. Kono K. “Cdk1-mediated DIAPH1 phosphorylation maintains metaphase cortical tension and inactivates the spindle assembly checkpoint at anaphase”  (2019 Mar) The 16th International Membrane Research Forum, OIST, Okinawa
  2. Kono K. “Mechanisms and consequences of cellular wound healing" (2019 Jan) The 1st OIST-OU Joint Symposium on Cell Biology and Immunology, Osaka U, Osaka
  3. Kono K. “Mechanisms and consequences of wound healing, from single cells to tissues” (2018 Nov) 48th Japanese Society for Wound Healing, Iino Hall & Conference Center, Tokyo Educational Keynote
  4. Kono K. “Mechanisms and consequences of plasma membrane repair” (2018 Oct) ABiS-GBI-OIST-ResonanceBio Joint Symposium ’Frontiers in Bioimaging’, OIST, Okinawa. 
  5. Kono K. “Cell surface damage determines cell fate in budding yeast” (2018 Sep) 70th Society for Biotechnology Japan Annual Meeting, Kansai University, Osaka 
  6. Kono K. “Yeast as a tool to reveal wound healing mechanisms” (2018 Sep) 22nd Yeast Joint Symposium, Kyusyu University,  Fukuoka 

 

Poster Presentation

  1. Masukagami Y, Moriyama Y, Barbee H, and Kono K. "The plasma membrane ultrastructure of aged cells" (2019 Jan) The 1st OIST-OU Joint Symposium on Cell Biology and Immunology, Osaka U, Osaka
  2. Masukagami Y, Moriyama Y, Barbee H, Matsui Y and Kono K. "The plasma membrane ultrastructure of aged cells" (2019 Mar) The 16th International Membrane Research Forum, OIST, Okinawa
  3. Moriyama Y, Masukagami Y, Barbee H, Matsui Y and Kono K. "The plasma membrane ultrastructure after cellular wound healing" (2019 Mar) The 16th International Membrane Research Forum, OIST, Okinawa

5. Intellectual Property Rights and Other Specific Achievements

Nothing to report

6. Meetings and Events

(1)    Mini Symposium Organization: 2019 Mar, "The 16th International Membrane Research Forum", OIST, Okinawa

(2)    Seminar

  • Date: September 28
  • Venue: OIST Campus Lab1 C016
  • Speaker: Dr. Riko Hatakeyama (University of Fribourg)
  • Date: December 25
  • Venue: OIST Campus Lab1 C016
  • Speaker: Dr. Sawako Yamashiro (Kyoto University Graduate School of Biostudies /Kyoto University Graduate School of Medicine)
  • Date: March 29
  • Venue: OIST Campus Lab1 D015
  • Speaker: Dr. Keisuke Ishihara (Max Planck Institute of Molecular Cell Biology)

7. Other

Nothing to report.