tailieunhanh - Báo cáo khoa học: Association of RNase L with a Ras GTPase-activating-like protein IQGAP1 in mediating the apoptosis of a human cancer cell-line

Mammalian intracellular ribonuclease L (RNase L) is a latent endoribo-nuclease that functions against viral infections as an apoptosis-inducing protein, and its activity requires intracellular 5¢-end-triphosphorylated-2¢,5¢ oligoadenylates (2-5A) as an activator. Previously, we showed that RNase L can be activated in human cancer cell line HT1080 by an RNA polymerase I inhibitor, 1-(3-C-ethynyl-b-d-ribo-pentofuranosyl)cytosine (3¢-ethynylcytidine; ECyd). | Association of RNase L with a Ras GTPase-activating-like protein IQGAP1 in mediating the apoptosis of a human cancer cell-line Akira Sato1 Tomoharu Naito1 Akiko Hiramoto1 Kazato Goda1 Takuya Omi1 Yukio Kitade2 Takuma Sasaki3 Akira Matsuda4 Masakazu Fukushima1 Yusuke Wataya1 and Hye-Sook Kim1 1 Department of Molecular Drug Informatics Faculty of PharmaceuticalSciences Okayama University Japan 2 Department of Biomolecular Science Faculty of Engineering Gifu University Japan 3 Department of Bioorganic Chemistry Schoolof Pharmacy Aichi Gakuin University Nagoya Japan 4 Department of MedicinalChemistry Faculty of PharmaceuticalSciences Hokkaido University Sapporo Japan Keywords apoptosis ECyd focused proteomics IQGAP1 RNase L Correspondence . Kim Faculty of Pharmaceutical Sciences Okayama University Tsushima Okayama 700-8530 Japan Fax 81 86 251 7974 Tel 81 86 251 7975 E-mail hskim @ Note Akira Sato and Tomoharu Naito contributed equally to this work Received 14 April 2010 revised 28 July 2010 accepted 26 August 2010 doi Mammalian intracellular ribonuclease L RNase L is a latent endoribonuclease that functions against viral infections as an apoptosis-inducing protein and its activity requires intracellular 5 -end-triphosphorylated-2 5 oligoadenylates 2-5A as an activator. Previously we showed that RNase L can be activated in human cancer cell line HT1080 by an RNA polymerase I inhibitor 1- 3-C-ethynyl-b-D-ribo-pentofuranosyl cytosine 3 -ethynylcytidine ECyd . In ECyd-treated cells knockdown of the RNase L resulted in a marked decrease in c-jun N-terminal kinase JNK phosphorylation thereby inhibiting apoptosis. We investigate RNase L binding partners by focused proteomic approach using immunoprecipitation with anti-RNase L IgG and mass spectrometry. We found that the IQ motif-containing Ras GTPase-activating-like protein 1 IQGAP1 can associate with RNase L and that phosphorylation occurs on the IQGAP1. ECyd-induced JNK