ORIGINAL ARTICLES

Cell Research (2006)16:539-547
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A Cdc2-related protein kinase hPFTAIRE1 from human brain interacting with 14-3-3 proteins

Yankun Gao, Mei Jiang, Tao Yang, Jian Ni, Jiangye Chen

¹State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-yang Road, Shanghai 200031, China

Correspondence: Jiangye Chen Tel: 86-21-54921251; Fax: 86-21-54921011 E-mail: jychen@sunm.shcnc.ac.cn Received 22 Apr 2005; revised 28 Mar 2006; accepted 11 Apr 2006; published online 15 Jun 2006

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hPFTAIRE1 (PFTK1), a Cdc2-related protein kinase, is highly expressed in human brain. It exhibits cytoplasmic distribution in Hela cells, although it contains two nuclear localization signals (NLSs) in its N-terminus. To search for its substrates and regulatory components, we screened a two-hybrid library by using the full-length hPFTAIRE1 as a bait. Four 14-3-3 isoforms (β, ε, η, τ) were identified interacting with the hPFTAIRE1. We found a putative 14-3-3 binding consensus motif (RHSSPSS) in the hPFTAIRE1, which overlapped with its second NLS. Deletion of the RHSSPSS motif or substitution of Ser¹¹⁹ with Ala in the conserved binding motif abolished the specific interaction between the hPFTAIRE1 and the 14-3-3 proteins. The mutant S120A hPFTAIRE1 also showed a weak interaction to the 14-3-3 proteins. The results suggested that the Ser¹¹⁹ is crucial for the interaction between hPFTAIRE1 and the 14-3-3 proteins. All the hPFTAIRE1 mutants distributed in cytoplasm of Hela cells and human neuroblastoma cells (SH-SY5Y) when fused to the C-terminus of a green fluorescent protein (GFP), indicating that binding with the 14-3-3 proteins does not contribute to the subcellular localization of the hPFTAIRE1, although the binding may be involved in its signaling regulation.

Cell Research (2006) 16:539-547. doi:10.1038/sj.cr.7310071; published online 15 June 2006

Keywords: hPFTAIRE1, 14-3-3 proteins, 14-3-3 binding motif, two-hybrid