AOP-1 Interacts with Cardiac-Specific Protein Kinase TNNI3K and Down-regulates Its Kinase Activity

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Yan Feng¹, Dong-Qing Liu², Zhen Wang³, Zhao Liu¹, Hui-Qing Cao², Lai-Yuan Wang², Na Shi², and Xian-Min Meng^2*

¹Department of Pathology, Medical College, Tongji University, 200092 Shanghai, China; fax: +86-21-6598-4636; E-mail: shuangfeiyan888@yahoo.com.cn; ruziliu0486@hotmail.com

²Molecular Medical Center for Cardiovascular Diseases, Fu Wai Cardiovascular Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, 100037 Beijing, China; fax: +86-10-6831-3012; E-mail: xmmengcn@yahoo.com; liudq1029@yahoo.com

³Department of Pharmacology, School of Basic Medical Sciences, Tongji Medical College, Huazhong University of Science and Technology, 430030 Wuhan, China; E-mail: wzhen2001@sina.com

^* To whom correspondence should be addressed.

Received April 2, 2007; Revision received June 4, 2007

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In the present study, a yeast two-hybrid screening system was used to identify the interaction partners of cardiac troponin I-interacting kinase (TNNI3K) that might serve as regulators or targets, and thus in turn to gain some insights on the roles of TNNI3K. After screening the adult heart cDNA library with a bait construct encoding the ANK motif of TNNI3K, antioxidant protein 1 (AOP-1) was isolated. The interaction between TNNI3K and AOP-1 was confirmed by the in vitro binding assay and coexpression experiments in vivo. The colocalization of TNNI3K and AOP-1 was clarified by confocal immunofluorescence. Moreover, coexpression of AOP-1 inhibited TNNI3K kinase activity in the in vitro kinase assay.

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KEY WORDS: AOP-1, protein kinase, protein-protein interaction, TNNI3K, yeast two-hybrid system

DOI: 10.1134/S0006297907110053

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