Molecular Cloning and Characterization of a Conserved Nuclear Serine (Threonine) Protein Kinase

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 92; no. 11; pp. 5022 - 5026
• Main Authors: Millward, Thomas, Cron, Peter, Hemmings, Brian A.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 23.05.1995; National Acad Sciences; National Academy of Sciences
• Subjects: Amino Acid Sequence; amino acid sequence predictions; Amino acids; Animals; Base Sequence; Biochemistry; Caenorhabditis elegans - enzymology; cDNA; Cell cycle; Cell Line; Cell lines; Cell Nucleus - enzymology; Cercopithecus aethiops; Cloning, Molecular; Complementary DNA; Conserved Sequence; COS cells; Deoxyribonucleic acid; DNA; DNA Primers; DNA, Complementary; Drosophila; Drosophila - embryology; Drosophila - enzymology; Drosophila melanogaster; Enzymes; genes; Glutathione Transferase - biosynthesis; HeLa Cells; Humans; Kinetics; man; Molecular Sequence Data; Mutagenesis, Site-Directed; Ndr protein; Nuclear Proteins - analysis; Nuclear Proteins - biosynthesis; Nuclear Proteins - chemistry; nucleotide sequence; Phosphorylation; Polymerase Chain Reaction; Protein-Serine-Threonine Kinases - analysis; Protein-Serine-Threonine Kinases - biosynthesis; Protein-Serine-Threonine Kinases - chemistry; protein-serine/threonine kinase; Proteins; Recombinant Fusion Proteins - analysis; Recombinant Fusion Proteins - biosynthesis; Recombinant Fusion Proteins - chemistry; Sequence Deletion; Sequence Homology, Amino Acid; Transfection
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.92.11.5022

Human, Drosophila melanogaster, and Caenorhabditis elegans cDNA clones encoding homologues of a serine(threonine) protein kinase (EC 2.7.1.37) (designated Ndr protein kinase) have been isolated and sequenced. The human and Drosophila cDNAs predict polypeptides of 54 kDa and 52 kDa, respectively, which share ≈80% amino acid similarity. Northern analysis of human tissues revealed a ubiquitously expressed 3.9-kb transcript. Recombinant GST-Ndr underwent intramolecular autophosphorylation on serine and threonine residues in vitro but failed to transphosphorylate several standard protein kinase substrates. Transfection of the human cDNA into COS-1 cells resulted in the appearance of an intense nuclear staining in cells analyzed by indirect immunofluorescence; deletion mutagenesis identified a short basic peptide, KRKAETWKRNRR, responsible for the nuclear accumulation of Ndr. Thus, Ndr is a conserved and widely expressed nuclear protein kinase. The closest known relative of this previously uncharacterized kinase is Dbf2, a budding yeast protein kinase required for the completion of nuclear division.