Ikenouchi Lab

Epithelial Cell Biology

In the textbooks, cell membranes are described as “gray two lines”. But actually, cells make many different lipid species. Although lipids are the main component of cells together with proteins, the functions of lipids or the physiological meaning of diversity of lipid species are not well elucidated.

Membrane model of Singer & Nicolson (1972)

The aim of our study from the viewpoint of basic science is to clarify the roles of individual lipid species by using epithelial polarity and cell adhesion as experimental systems. The research purpose for clinical science is to find novel therapeutic targets in diseases correlated with epithelial-polarity disorders and epithelial-mesenchymal transition, such as cancer, polycystic kidney disease and pulmonary fibrosis.

Research

Epithelial cells are constitutively polarized to play fundamental functions such as vectorial transport. There are two membrane domains of epithelial cells, the apical membrane and basolateral membrane. These membrane domains are separated by cell adhesion apparatus. Most of our previous studies concerning epithelial polarity and cell adhesion have been focused on identification of new genes or elucidation of protein-protein interactions(for example, tricellulin of FRMD4A)

Although lipids are the main component of cells together with proteins, the functions of lipids or the physiological meaning of diversity of lipid species are not well elucidated. To analyze membrane lipids, we recently developed a new method to determine the lipid composition of plasma membrane (Ikenouchi et al. 2012).Taking advantage of this method, we succeeded in clarifying the difference of lipid composition between the apical membrane and the basolateral membrane and found that sphingomyelin plays essential roles in the formation of microvilli (Ikenouchi et al. 2013).

Furthermore, we identified several epithelial-cell specific lipids by comparing the lipid profile between epithelial cells and mesenchymal cells, taking advantage of previously established cell lines (Ikenouchi et al.2003).Currently we try to elucidate functional roles of these lipids by examining whether knock-down of biosynthetic enzymes in cultured epithelial cells affect epithelial polarity and cell-cell adhesion.

The aim of our study from the viewpoint of basic science is to clarify the importance of individual lipid species by using epithelial cells as an experimental model. The research purpose for clinical science is to find novel therapeutic targets in diseases correlated with epithelial-polarity disorders and epithelial-mesenchymal transition, such as cancer, polycystic kidney disease and pulmonary fibrosis.

  • Elucidation of roles of lipids in the formation of epithelial polarity and cell adhesion
  • Elucidation of the organizing principles of living cell membrane by combining synthetic biological approaches and cell biological approaches

Members

Junichi Ikenouchi

Professor M.D., Ph.D.  [Bio]

Assistant Professor Kanji Okumoto Ph.D.  [Bio]
Assistant Professor Kenji Matsuzawa Ph.D. 
D1 Kana Aoki, Kenta Shigetomi
M2 Hayato Ooga, Yuta Bannouchi, Takuya Himoto
M1 Yumiko Ono, Tomohiro Hirano
B4 Akari Nakamura, Yuki Mochizuki

 

Lab photos
Recent photos are uploaded to Facebook page.

Publication

Recent Publications  [More]

(† : Corresponding author)
(* : Co-first author)

Nishimura T, Ito S, Saito H, Hiver S, Shigetomi K, Ikenouchi J, †Takeichi M.
DAAM1 stabilizes epithelial junctions by restraining WAVE complex-dependent lateral membrane motility.
J Cell Biol. 2016 Nov 21;215(4):559-573. [Pubmed]

†Ikenouchi J.
How do cells sense actin cortex-free membrane?
Cell Cycle. 2016 Oct 17;15(20):2687-8. [Pubmed]

†Ikenouchi J, Aoki K.
Membrane bleb : a seesaw game of two small GTPases.
Small GTPases. 2016 [Pubmed] (Review)

Aoki K, Maeda F, Nagasako T, Mochizuki Y, Uchida S, and †Ikenouchi J
A RhoA and Rnd3 cycle regulates actin reassembly during membrane blebbing
Proc Natl Acad Sci U S A. 2016 Mar 29;113(13):E1863-71. [Pubmed]

Shiomi R, Shigetomi K, Inai T, Sakai M, †Ikenouchi J.
CaMKII regulates the strength of the epithelial barrier.
Sci Rep. 2015 Aug 18;5:13262. [Pubmed]

Arita Y, Nishimura S, Ishitsuka R, Kishimoto T, Ikenouchi J, Ishii K, Umeda M, Matsunaga S, Kobayashi T, †Yoshida M.
Targeting cholesterol in a liquid-disordered environment by theonellamides modulates cell membrane order and cell shape.
Chem Biol. 2015 May 21;22(5):604-10. [Pubmed]

Ohoka A, Kajita M, Ikenouchi J, Yako Y, Kitamoto S, Kon S, Ikegawa M, Shimada T, Ishikawa S, †Fujita Y.
EPLIN is a crucial regulator for extrusion of RasV12-transformed cells.
J Cell Sci. 2015 Feb 15;128(4):781-9. [Pubmed]

Oda Y, Otani T, Ikenouchi J, †Furuse M.
Tricellulin regulates junctional tension of epithelial cells at tricellular contacts through Cdc42.
J Cell Sci. 2014 Oct 1;127(Pt 19):4201-12. [Pubmed]

†Ikenouchi J, Hirata M, Yonemura S, Umeda M.
Sphingomyelin clustering is essential for the formation of microvilli.
J Cell Sci. 2013 Aug 15;126(Pt 16):3585-92. [Pubmed]

Recruitment

We are in the recruitment of graduate students, postdoctoral and research assistant.

Contact

Kyushu University, Department of Cell Biology, Faculty of Sciences Professor
Junichi Ikenouchi M.D., Ph.D.
TEL: +81-92-802-4292
E-mail: ikenouchi.junichi.033(at-mark)m.kyushu-u.ac.jp

West 1st Building W1-D-809, 744 Moto-oka Nishi-ku Fukuoka