SIRT1 Regulates Thyroid-Stimulating Hormone Release by Enhancing PIP5Kc Activity through Deacetylation of Specific Lysine Residues in Mammals Sayaka Akieda-Asai1,2, Nobuhiro Zaima2,3, Koji Ikegami2,3, Tomoaki Kahyo2,4, Ikuko Yao2,5, Takahiro Hatanaka2, Shun-ichiro Iemura6, Rika Sugiyama 7 , Takeaki Yokozeki7, Yoshinobu Eishi8, Morio Koike8, Kyoji Ikeda9, Takuya Chiba10, Haruyoshi Yamaza10,11, Isao Shimokawa10, Si-Young Song 2 , Akira Matsuno12, Akiko Mizutani13, Motoji Sawabe14, Moses V. Chao15, Masashi Tanaka16, Yasunori Kanaho 7 , Tohru Natsume 6 , Haruhiko Sugimura4, Yukari Date1, Michael W. McBurney17, Leonard Guarente18, Mitsutoshi Setou2,3* 1 Frontier Science Research Center, University of Miyazaki, Miyazaki, Japan, 2 Mitsubishi Kagaku Institute of Life Sciences (MITILS), Tokyo, Japan, 3 Department of Molecular Anatomy, Hamamatsu University School of Medicine, Shizuoka, Japan, 4 Department of Pathology, Hamamatsu University School of Medicine, Shizuoka, Japan, 5 Department of Medical Chemistry, Kansai Medical University, Osaka, Japan, 6 National Institute of Advanced Industrial Science and Technology, Biomedicinal Information Research Center, Tokyo, Japan, 7 Department of Physiological Chemistry, Graduate School of Comprehensive Human Sciences and Institute of Basic Medical Sciences, University of Tsukuba, Ibaraki, Japan, 8 Department of Human Pathology, Tokyo Medical and Dental University, Tokyo, Japan, 9 Department of Bone and Joint Disease, Research Institute, National Center for Geriatrics and Gerontology, Aichi, Japan, 10 Department of Investigative Pathology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan, 11 Section of Pediatric Dentistry, Division of Oral Health, Growth and Development, Faculty of Dental Science, Kyushu University, Fukuoka, Japan, 12 Department of Neurosurgery, Teikyo University Chica Medical Center, Chiba, Japan, 13 Basic Medical Science and Molecular Medicine, Tokai University School of Medicine, Kanagawa, Japan, 14 Department of Pathology and Bioresource Center for Geriatric Research, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, Japan, 15 Molecular Neurobiology Program, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, New York, United States of America, 16 Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan, 17 Ottawa Hospital Research Institute and Department of Medicine, University of Ottawa, Ottawa, Canada, 18 Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America Abstract Background: SIRT1, a NAD-dependent deacetylase, has diverse roles in a variety of organs such as regulation of endocrine function and metabolism. However, it remains to be addressed how it regulates hormone release there. Methodology/Principal Findings: Here, we report that SIRT1 is abundantly expressed in pituitary thyrotropes and regulates thyroid hormone secretion. Manipulation of SIRT1 level revealed that SIRT1 positively regulated the exocytosis of TSH- containing granules. Using LC/MS-based interactomics, phosphatidylinositol-4-phosphate 5-kinase (PIP5K)c was identified as a SIRT1 binding partner and deacetylation substrate. SIRT1 deacetylated two specific lysine residues (K265/K268) in PIP5Kc and enhanced PIP5Kc enzyme activity. SIRT1-mediated TSH secretion was abolished by PIP5Kc knockdown. SIRT1 knockdown decreased the levels of deacetylated PIP5Kc, PI(4,5)P2, and reduced the secretion of TSH from pituitary cells. These results were also observed in SIRT1-knockout mice. Conclusions/Significance: Our findings indicated that the control of TSH release by the SIRT1-PIP5Kc pathway is important for regulating the metabolism of the whole body. Citation: Akieda-Asai S, Zaima N, Ikegami K, Kahyo T, Yao I, et al. (2010) SIRT1 Regulates Thyroid-Stimulating Hormone Release by Enhancing PIP5Kc Activity through Deacetylation of Specific Lysine Residues in Mammals. PLoS ONE 5(7): e11755. doi:10.1371/journal.pone.0011755 Editor: Mikhail V. Blagosklonny, Roswell Park Cancer Institute, United States of America Received April 7, 2010; Accepted June 29, 2010; Published July 23, 2010 Copyright: 2010 Akieda-Asai et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This study was supported by the Mitsubishi Kagaku Institute of Life Sciences and WAKATE S for Scientific Research to M.S. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. * E-mail: setou@hama-med.ac.jp Introduction Sir2 (silent information regulator 2) is a NAD+-dependent protein deacetylase [1,2]. In yeast, Sir2 mediates transcriptional silencing at telomeres and regulates the pace of aging [3]. In C.elegans, one of the Sir2 orthologues, Sir2.1, has been shown to forestall aging by acting in a DAF-16 signaling pathway [4]. In mammals, SIRT1, the closest mammalian orthologue of Sir2, has diverse roles in a variety of organs or tissues [5], and molecular mechanisms underlying the broad SIRT1 functions are highly complicated. SIRT1 is shown to be mainly involved in the regulations of whole body metabolism and physical activity. SIRT1 promotes free fatty acid mobilization of fat from white adipose tissues by repressing peroxisome proliferator-activated receptor-c (PPARc), a nuclear receptor that promotes adipogen- esis [6]. SIRT1 also regulates the gluconeogenic and glycolytic PLoS ONE | www.plosone.org 1 July 2010 | Volume 5 | Issue 7 | e11755