A Cdc2-related protein kinase hPFTAIRE1 from human brain interacting with 14-3-3 proteins

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 hPFTAIRE 1, which overlapped with its second NLS. Deletion of the RHSSPSS motif or substitution of Ser^119 gwithAla in the conserved binding motif abolished the specific interaction between the hPFTAIRE 1 and the 14-3 -3 proteins. The mutant S 120A hPFTAIRE1 also showed a weak interaction to the 14-3-3 proteins. The results suggested that the Ser^119 is crucial for the interaction between hPFTAIREI 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.     

Cloning and characterization of the CDZFP gene which encodes a putative zinc finger protein.

We report here the cloning and characterization of a novel human cytoplasm-distribution zinc finger protein (CDZFP) gene, isolated from human ovary cDNA library, and mapped to 4p12 by searching the UCSC genomic database. The CDZFP cDNA is 1793 base pairs in length and contains an open reading frame (ORF) encoding 236 amino acids. The CDZFP gene consists of 7 exons and encodes a putative zinc finger protein with a transmembrane region and two zinc finger motifs. Subcellular localization demonstrated that CDZFP protein was located in the cytoplasm when overexpressed in Hela cells and northern blot analysis revealed that CDZFP was ubiquitously expressed in 16 human tissues.     

A Novel cdc2-Related Protein Kinase Expressed in the Nervous System

Abstract: We report the cloning and characterization of a cDNA encoding a cdc2-related protein kinase, named PFTAIRE, that is expressed primarily in the postnatal and adult nervous system. We have demonstrated by in situ hybridization and indirect immunofluorescence that several populations of terminally differentiated neurons and some neuroglia expressed PFTAIRE mRNA and protein. In neurons, PFTAIRE protein was localized in the nucleus and cytoplasm of cell bodies. The anatomical, cellular, and ontogenic patterns of PFTAIRE expression in the nervous system differed from those of p34^cdc2 and cdk5, which are expressed in brain and several other mitotic tissues. Proteins of ～58–60 kDa coprecipitated specifically with PFTAIRE from cytosolic protein preparations of adult mouse brain and transfected cells. These proteins appeared to be the major endogenous substrates associated with this kinase activity. The temporal and spatial expression patterns of PFTAIRE in the postnatal and adult nervous system suggest that PFTAIRE kinase activity may be associated with the postmitotic and differentiated state of cells in the nervous system and that its function may be distinct from those of p34^cdc2 and cdk5.