Rational role of amino acids in intestinal epithelial cells (Review).
There is much interest in precise functions of amino acids on mammalian growth and development. Some of amino acids play important roles in the control of gene expression by controlling the initiation phase of mRNA translation. The signal induced by leucine or arginine may stimulate cell growth. On the other hand, the other signal induced by glutamine may stimulate cellular proliferation and increase cell number, but inhibit the growth of cell size. However, there was no clear evidence that an individual amino acid specifically works as a signaling molecule. In our recent study, not only leucine, but also arginine is shown to activate the mTOR signaling pathway in rat intestinal epithelial cells. Furthermore, regarding L-Glutamine, an important amino acid that is required for culturing of numerous cell types, including rat intestinal epithelial cells, we have shown that it had an inhibitory effect on leucine- or arginine-induced activation of the mTOR signaling pathway. We have demonstrated that L-Glutamine inhibited the activation of p70 S6 kinase and phosphorylation of 4E-BP1 induced by arginine or leucine in rat intestinal epithelial cells. Based on these results, we are planning to confirm the effect of each amino acid including glutamine in an in vivo model using new born mice.
Naomoto
Yoshio
Y
Department of Gastroenterological Surgery, Transplant, and Surgical Oncology, Graduate School of Medicine and Dentistry, Okayama University, 2-5-1, Okayama 700-8558, Japan. ynaomoto@md.okayama-u.ac.jp
Yamatsuji
Tomoki
T
Shigemitsu
Kaori
K
Ban
Hidetoshi
H
Nakajo
Tohru
T
Shirakawa
Yasuhiro
Y
Motok
Takayuki
T
Kobayashi
Masahiko
M
Gunduz
Mehmet
M
Tanaka
Noriaki
N
D000596:Amino Acids / Q000502:physiology*; D000818:Animals; D004847:Epithelial Cells / Q000502:physiology*; D007413:Intestinal Mucosa / Q000166:cytology / Q000502:physiology*; D051379:Mice; D008954:Models, Biological; D011494:Protein Kinases / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D058570:TOR Serine-Threonine Kinases
D000596:Amino Acids; D011494:Protein Kinases; C546843:mTOR protein, mouse; C546845:mTOR protein, rat; D058570:TOR Serine-Threonine Kinases