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Volume 13 (1988)
- Issue 6 Pages 459-
- Issue 5 Pages 359-
- Issue 4 Pages 271-
- Issue 3 Pages 193-
- Issue 2 Pages 105-
- Issue 1 Pages 1-
Volume 13, Issue 6
Displaying 1-6 of 6 articles from this issue
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Atsuo Tanaka, Yasuhiko Kakui, Hidetoshi Uemura, Hidekazu Matsuoka, Tad ...1988 Volume 13 Issue 6 Pages 459-470
Published: 1988
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSIt was reported in our previous studies that the "spongy degeneration-like" changes of human tumor cells were detected by coculture with human embryonic fibroblasts in vitro. It was discovered that the degenerative changes were mediated by a factor secreted from human em-bryonic fibroblasts. This factor was named the tumor-degenerating factor (TDF). The present study found that fibronectin inhibited TDF activity while TDF inhibited cell attachment mediated by fibronectin. It was possible that these mutual inhibitions were due to the direct binding of the TDF molecule to the fibrOnectin molecule. Since it is well known that fibronectin is composed of multiple domains which differ in their biological activities, this study also at-tempted to clarify which domain(s) inhibit TDF activity, through the use oftrypsin, thermolysin and 2-nitro-5-thiocyanobenzoic acid (NTCB). It is conclud-ed that multiple domains of fibronectin are required for the inhibition of TDF activity.View full abstractDownload PDF (1112K) -
Masamichi Hirai, Masayuki Amagai, Shingo Tajima, Takeji Nishikawa, Nob ...1988 Volume 13 Issue 6 Pages 471-480
Published: 1988
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSDNA synthesis of WF-1 fibroblasts derived from a patient with Werner's syndrome was stimulated by fetal calf serum and adult human serum but not by various mitogens including epidermal growth factor, platelet-derived growth factor (PDGF), fibroblast growth factor, insulin and 12-O- tetradecanoylphorbol-13-acetate (TPA). To clarify the cause of nonrespon-siveness to these mitogens, we compared the rate of protein phosphorylation in normal fibroblasts HF-O and Werner's WF-1 cells. PDGF and TPA enhanced the phosphorylation of a Mr 80 K protein, which is known to be a substrate for protein kinase C, both in HF-O and WF-1 cells. This indicates that the pathway involving PDGF receptor, phosphatidylinositol turnover and protein kinase C activation is operational in WF-1 cells. Several species of phosphoproteins of Mr 250 K, 135 K, 110 K, 78 K and 42 K were detected in normal HF-O cells by immunoprecipitation using an anti-phosphotyrosine antibody. The same species of phosphoproteins were detected in Werner's WF-1 cells at passage 6, but only when treated with various mitogens and were not detected in WF-1 cells at passage 10 even after the PDGF- or TPA-treatment. These results sug-gest that the reduction of phosphorylation of these target proteins may be in part responsible for the diminished mitogenic responsiveness of Werner's fibroblasts.View full abstractDownload PDF (815K) -
Hatsue Morita, Hidetaro Yasumitsu, Hiroshi Harada, Makoto Umeda, Toshi ...1988 Volume 13 Issue 6 Pages 481-493
Published: 1988
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSSeveral cell lines growing in protein- and lipid-free synthetic medium secreted cell-adhesive protein(s) into the medium. The conditioned medium (CM) of one of these cell lines, mouse L•P3, showed the highest cell at-tachment-promoting activity (CPA) among them. Cell-adhesive protein(s) in the CM of L•P3 cells (L•P3-CM) were separated into two types by sequential affinity column chromatography employing gelatin-Sepharose 4B and heparin-Sepharose 4B. One was a gelatin- and heparin-binding cell-adhesive protein (GCP), and was identified as a cellular form of mouse fibronectin. The other was a gelatin-non-binding and heparin-binding cell-adhesive protein (GNCP). The CPA of GNCP preparation was effective for the cell-attachment and spreading of both epithelial and fibroblastic cells. The CPA of GNCP prepara-tion was not blocked by the antiserum and scarcely inhibited in the presence of the synthetic cell attachment-promoting peptide Gly-Arg-Gly-Asp-Ser-Pro, a competitive inhibitor of fibronectin. This suggests that the structure of the cell-attachment site of GNCP is different from that of fibronectin. The GNCP preparation showed little cross-reactivity with anti-mouse laminin antiserum in enzyme-linked immunosorbent assay (ELISA). These results demonstrate the possibility that GNCP in L•P3-CM is a novel cell-adhesive protein distinct from fibronectin or laminin. The secretion of the two types of cell-adhesive pro-teins by L•P3 cells is discussed.View full abstractDownload PDF (1435K) -
Masayasu Yamada, Makoto Kawaguchi, Haruo Takamiya, Hiroyoshi Wada, Toh ...1988 Volume 13 Issue 6 Pages 495-513
Published: 1988
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSAn epithelial cell line, designated as SGE1, has been established from isolated rat renal glomeruli. SGE1 cells are able to grow continuously in a serum-free medium at similar growth rates to those in the medium containing serum. Quantitative studies of the cells in the serum-free condition demonstrated that SGE1 cells required a collagen type I or IV, fibronectin, or laminin-coated substratum for adhesion and growth, and among them, collagen type I and IV were most effective. Essential medium supplements for the adhesion and growth were epidermal growth factor and transferrin, respectively, and both effects were noticeably enhanced with linoleic acid. Morphological observation found that in a monolayer culture, SGE1 cells formed domes, and in a collagen embedding culture, they formed cystic spheres having features of a simple cuboidal epithelium, polarized formation of microvilli and tight junctions as well as a lateral cell membrane with cytoplasmic projections. In addition, SGE1 cells expressed Fx1A antigens, which are nephritogenic antigens on their microvilli.View full abstractDownload PDF (12633K) -
Tadashi Shimo-Oka, Yuka Hasegawa, Ichio Ii1988 Volume 13 Issue 6 Pages 515-524
Published: 1988
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSHuman diploid fibroblasts (TIG-3) were shown to attach and spread onto substrata coated with collagen, fibronectin, laminin and vitronec-tin. The cell attachment to these proteins required divalent cations. Mg2+ stimulated the cell attachment to all the proteins, while Ca2+ alone was not effec-tive for the attachment to collagen and laminin. A mild trypsin treatment had prevented cells from attaching to the laminin, while it had no effect on the at-tachment to the other proteins. The fibronectin fragment, which retained cell binding activity, inhibited the cells from attaching and spreading onto fibronec-tin, but it did not cause any inhibition on the other proteins. The synthetic pep-tide GRGDSP inhibited the cells from attaching and spreading onto fibronectin and vitronectin, while it did not cause any inhibition on collagen and laminin. In attempts to isolate distinct receptors for these proteins, we were able to purify proteins very similar to the fibronectin and vitronectin receptors of human placenta. Based on the differential properties of the attachment of TIG-3 cells to these proteins and biochemical data, we indicate that human diploid fibroblasts have distinctive binding sites (receptors) for collagen, fibronectin, laminin and vitronectin.View full abstractDownload PDF (4983K) -
Hiroshi Hosoya, Takashi Takagi, Issei Mabuchi, Hisashi Iwaasa, Hikoich ...1988 Volume 13 Issue 6 Pages 525-532
Published: 1988
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe 15 kDa protein is the most abundant low molecular weight Ca2+-binding protein, different from calmodulin, in eggs of sea urchin, Hemicentrotus pulcherrimus (9). The data from the amino acid sequence demonstrated that the 15 kDa protein belonged to the troponin C superfamily. Based on immunofluorescent and immunomicroscopic observations, we showed that the 15 kDa protein localized in the nuclei of fertilized eggs and mitotic apparatus of dividing eggs. Microinjection of the antibody against 15 kDa protein into sea urchin blastomeres resulted in the arresting of cell division. These results suggest that the 15 kDa protein plays an important role in mitosis of sea urchin egg.View full abstractDownload PDF (3820K)
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