Biomedical subjects

D Nagakubo

Publications and source records attributed to D Nagakubo.

3 recordsLinked to original sources

PubMed2000

Binding of a large chondroitin sulfate/dermatan sulfate proteoglycan, versican, to L-selectin, P-selectin, and CD44.

Here we show that a large chondroitin sulfate proteoglycan, versican, derived from a renal adenocarcinoma cell line ACHN, binds L-selectin, P-selectin, and CD44. The binding was mediated by the interaction of the chondroitin sulfate (CS) chain of versican with the carbohydrate-binding domain of L- and P-selectin and CD44. The binding of versican to L- and P-selectin was inhibited by CS B, CS E, and heparan sulfate (HS) but not by any other glycosaminoglycans tested. On the other hand, the binding to CD44 was inhibited by hyaluronic acid, chondroitin (CH), CS A, CS B, CS C, CS D, and CS E but not by HS or keratan sulfate. A cross-blocking study indicated that L- and P-selectin recognize close or overlapping sites on versican, whereas CD44 recognizes separate sites. We also show that soluble L- and P-selectin directly bind to immobilized CS B, CS E, and HS and that soluble CD44 directly binds to immobilized hyaluronic acid, CH, and all the CS chains examined. Consistent with these results, structural analysis showed that versican is modified with at least CS B and CS C. Thus, proteoglycans sufficiently modified with the appropriate glycosaminoglycans should be able to bind L-selectin, P-selectin, and/or CD44.

Animals↗

PubMed2000

PAP-1, a novel target protein of phosphorylation by pim-1 kinase.

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.

Amino Acid Sequence↗

PubMed1997

DJ-1, a novel oncogene which transforms mouse NIH3T3 cells in cooperation with ras.

We have isolated and characterized the cDNA encoding a novel protein designated DJ-1. DJ-1, sharing no significant homology with the sequences so far reported, did not show transactivation activity in the Gal4 recombinant system, but transformed mouse NIH3T3 cells by itself. Furthermore, DJ-1 showed a cooperative transforming activity with H-Ras, more than 3 times as strong as the activity of ras/myc combination. DJ-1 was ubiquitously expressed in various human tissues, and the expression was induced by growth stimuli. Moreover, DJ-1 translocated from cytoplasm to nuclei in the S phase of the cell cycle. DJ-1 is thus suggested to be a novel mitogen-dependent oncogene product involved in a Ras-related signal transduction pathway.

3T3 Cells↗