Analytical Sciences

Abstract − Analytical Sciences, 35(1), 57 (2019).

Membrane Dynamics Induced by a Phosphatidylinositol 3,4,5-Trisphosphate Optogenetic Tool
Yoshibumi UEDA,*1,*2 Tatsuhito II,*3 Yuki AONO,*1 Naotoshi SUGIMOTO,*4 Seiichi SHINJI,*5 Hiroshi YOSHIDA,*5 and Moritoshi SATO*1
*1 Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan
*2 AMED-PRIME, Japan Agency for Medical Research and Development, Tokyo, Japan
*3 Department of Veterinary Pathology, School of Veterinary Medicine, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino, Tokyo 180-8602, Japan
*4 Department of Physiology, Graduate School of Medical Science, Kanazawa University, Kanazawa, Ishikawa, Japan
*5 Department of Gastrointestinal and Hepato-Biliary-Pancreatic Surgery, Nippon Medical School, Bunkyo, Tokyo 113-8603, Japan
Membrane dynamic structures such as filopodia, lamellipodia, and ruffles have important cellular functions in phagocytosis and cell motility, and in pathological states, such as cancer metastasis. Phosphatidylinositol 3,4,5-trisphosphate (PIP3) is a crucial lipid that regulates PIP3 dynamics. Investigations of how PIP3 is involved in these functions have mainly relied on pharmacological interventions, and therefore have not generated detailed spatiotemporal information concerning membrane dynamics upon PIP3 production. In the present study, we applied an optogenetic approach using the CRY2–CIBN system. Using this system, we revealed that local PIP3 generation induced directional cell motility and membrane ruffles in COS7 cells. Furthermore, combined with structured illumination microscopy (SIM), membrane dynamics were investigated with high spatial resolution. We observed PIP3-induced apical ruffles and unique actin fiber behavior in that a single actin fiber protruded from the plasma membrane was taken up into the plasma membrane without depolymerization. This system has the potential to investigate other high-level cell motility and dynamic behaviors, such as cancer cell invasion and wound healing with high spatiotemporal resolution, and could provide new insights of biological sciences for membrane dynamics.