Human TAO kinase 1 induces apoptosis in SH-SY5Y cells

• Published in: Cell biology international 2008, Vol.32 (1), p.151-156
• Main Authors: Wu, Ming-Fang, Wang, Shyang-Guang
• Format: Article
• Language: English
• Subjects: Anthracenes - pharmacology; Apoptosis; Apoptosis - drug effects; Apoptosis - physiology; Caspase 3 - metabolism; Cell Line, Tumor; Human; Humans; JNK Mitogen-Activated Protein Kinases - metabolism; MAP Kinase Kinase Kinases - metabolism; Neuroblastoma - metabolism; Neuroblastoma - pathology; Protein Structure, Tertiary; Protein-Serine-Threonine Kinases; SH-SY5Y cells; TAO kinase 1; Transfection
• ISSN: 1065-6995; 1095-8355
• DOI: 10.1016/j.cellbi.2007.08.006

The human TAO kinase 1 (hTAOK1) is a member of the Ste20 group of kinases with the kinase domain located at the N-terminus. The rat homologue, originally named TAO1, has been demonstrated to be highly expressed in brain. In this study, the human TAO kinase 1 was transfected into human neuroblastoma SH-SY5Y cells and its biological effects on the cell morphology were observed by co-expressing the enhanced green fluorescent protein (EGFP). It was found that after 16 h of transfection the cells had shrunk, and finally became rounded when transfected with wild-type or mutant K57A genes encoding either the kinase domain (residues 1–376) or the full-length molecule (residues 1–1001). Thirty-four hours after transfection, cells floated and apoptotic bodies were observed after nuclear staining with DAPI. On the other hand, the cells that were transfected with the gene encoding the C-terminal regulatory region (residues 377–1001) of hTAOK1, appeared to remain unchanged. In order to know the signaling events involved in the above biological phenomena, caspase-3-like activities of the transfected cells were measured in the absence or presence of JNK inhibitor SP600125, in which caspase-3 and JNK (C-jun-N-terminal kinase) are both known to be critical components of the neuronal apoptosis. The results showed that the apoptotic cells exhibited elevated caspase-3-like activity, which could be reduced by SP600125 to some extent. It is concluded that human TAO kinase 1 induces apoptosis in SH-SY5Y cells and the kinase domain is essential, but its catalytic activity seems to be dispensable in this case.