PAP‐1, a novel target protein of phosphorylation by Pim‐1 kinase

• Published in: European journal of biochemistry Vol. 267; no. 16; pp. 5168 - 5178
• Main Authors: Maita, Hiroshi, Harada, Yosuke, Nagakubo, Daisuke, Kitaura, Hirotake, Ikeda, Masako, Tamai, Katsuyuki, Takahashi, Kazuhiko, Ariga, Hiroyoshi, Iguchi‐Ariga, Sanae M. M.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01-08-2000
• Subjects: Amino Acid Sequence; Animals; Annexin A5 - metabolism; Base Sequence; Binding Sites; Cloning, Molecular; COS Cells; Humans; Jurkat Cells; Kinetics; Molecular Sequence Data; Pancreatitis-Associated Proteins; PAP‐1; Phosphorylation; Pim‐1; Protein-Serine-Threonine Kinases - metabolism; Proto-Oncogene Proteins - chemistry; Proto-Oncogene Proteins - genetics; Proto-Oncogene Proteins - metabolism; Proto-Oncogene Proteins c-pim-1; Recombinant Proteins - chemistry; Recombinant Proteins - metabolism; Sequence Alignment; Sequence Homology, Amino Acid; Substrate Specificity; U937 Cells
• ISSN: 0014-2956; 1432-1033
• DOI: 10.1046/j.1432-1327.2000.01585.x

Protooncogene, pim‐1, has been reported to be a predisposition for lymphomagenesis along with myc, and its protein product, Pim‐1, has been shown to be a serine/threonine protein kinase, whose activity is involved in proliferation and differentiation of blood cells. The signal transduction pathways neither to nor from Pim‐1, however, have been clarified. We have cloned a cDNA encoding a novel Pim‐1 binding protein, PAP‐1, comprising 213 amino acids with a basic amino‐acid cluster near the C‐terminus. PAP‐1 was colocalized with Pim‐1 in human HeLa cell nuclei. The in vitro binding assays using GST fusion proteins of the wild‐type and various deletion mutants revealed that the whole molecule of Pim‐1 is required for the binding activity to PAP‐1 and that Pim‐1 binds to the region from amino‐acid numbers 1–147 of PAP‐1, or to two segments in the region. The association of PAP‐1 with Pim‐1 was also shown in vivo in transfected cells. Furthermore, PAP‐1 was phosphorylated in vitro by Pim‐1, but not a kinase‐negative Pim‐1 mutant. The two serine residues of PAP‐1 at amino acids 204 and 206 near the C‐terminus were phosphorylated by Pim‐1. PAP‐1 is thus thought to be a target protein for Pim‐1 kinase.