Physical and functional interactions between ZIP kinase and UbcH5.

Norihiko Ohbayashi, Katsuya Okada, Shiho Kawakami, Sumihito Togi, Noriko Sato, Osamu Ikeda, Shinya Kamitani, Ryuta Muromoto, Yuichi Sekine, Taro Kawai, Shizuo Akira, Tadashi Matsuda

Department of Immunology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-Ku Kita 12 Nishi 6, Sapporo 060-0812, Japan.

Biochemical and biophysical research communications 2008 Aug 8

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Zipper-interacting protein kinase (ZIPK) is a widely expressed serine/threonine kinase that has been implicated in cell death and transcriptional regulation, but its mechanism of regulation remains unknown. In our previous study, we showed that leukemia inhibitory factor stimulated threonine-265 phosphorylation of ZIPK, thereby leading to phosphorylation and activation of signal transducer and activator of transcription 3. Here, we identified UbcH5c as a novel ZIPK-binding partner by yeast two-hybrid screening. Importantly, we found that UbcH5c induced ubiquitination of ZIPK. Small-interfering RNA-mediated reduction of endogenous UbcH5 expression decreased ZIPK ubiquitination. Furthermore, coexpression of UbcH5c with ZIPK influenced promyelocytic leukemia protein nuclear body (PML-NB) formation. These results suggest that UbcH5 regulates ZIPK accumulation in PML-NBs by interacting with ZIPK and stimulating its ubiquitination.

Citation

Norihiko Ohbayashi, Katsuya Okada, Shiho Kawakami, Sumihito Togi, Noriko Sato, Osamu Ikeda, Shinya Kamitani, Ryuta Muromoto, Yuichi Sekine, Taro Kawai, Shizuo Akira, Tadashi Matsuda. Physical and functional interactions between ZIP kinase and UbcH5. Biochemical and biophysical research communications. 2008 Aug 8;372(4):708-12