scholarly journals Involvement of chondroitin sulfate synthase-3 (chondroitin synthase-2) in chondroitin polymerization through its interaction with chondroitin synthase-1 or chondroitin-polymerizing factor

2007 ◽  
Vol 403 (3) ◽  
pp. 545-552 ◽  
Author(s):  
Tomomi Izumikawa ◽  
Toru Uyama ◽  
Yuka Okuura ◽  
Kazuyuki Sugahara ◽  
Hiroshi Kitagawa
Keyword(s):  
Rna Interference ◽  
Chondroitin Sulfate ◽  
Chain Length ◽  
Hela Cells ◽  
Polymerase Activity

Previously, we have demonstrated that co-expression of ChSy-1 (chondroitin synthase-1), with ChPF (chondroitin-polymerizing factor) resulted in a marked augmentation of glycosyltransferase activities and the expression of the chondroitin polymerase activity of ChSy-1. These results prompted us to evaluate the effects of co-expression of the recently cloned CSS3 (chondroitin sulfate synthase-3) with ChPF, because ChSy-1 and CSS3 have similar properties, i.e. they possess GalNAcT-II (N-acetylgalactosaminyltransferase-II) and GlcAT-II (glucuronyltransferase-II) activities responsible for the elongation of CS (chondroitin sulfate) chains but cannot polymerize chondroitin chains by themselves. Co-expressed CSS3 and ChPF showed not only substantial GalNAcT-II and GlcAT-II activities but also chondroitin polymerase activity. Interestingly, co-expressed ChSy-1 and CSS3 also exhibited polymerase activity. The chain length of chondroitin formed by the co-expressed proteins in various combinations was different. In addition, interactions between any two of ChSy-1, CSS3 and ChPF were demonstrated by pull-down assays. Moreover, overexpression of CSS3 increased the amount of CS in HeLa cells, while the RNA interference of CSS3 resulted in a reduction in the amount of CS in the cells. Altogether these results suggest that chondroitin polymerization is achieved by multiple combinations of ChSy-1, CSS3 and ChPF. Based on these characteristics, we have renamed CSS3 ChSy-2 (chondroitin synthase-2).

FAM20B is a kinase that phosphorylates xylose in the glycosaminoglycan–protein linkage region

2009 ◽  
Vol 421 (2) ◽  
pp. 157-162 ◽  
Author(s):  
Toshiyasu Koike ◽  
Tomomi Izumikawa ◽  
Jun-Ichi Tamura ◽  
Hiroshi Kitagawa
Keyword(s):  
Rna Interference ◽  
Heparan Sulfate ◽  
Chondroitin Sulfate ◽  
Hela Cells ◽  
Unknown Function ◽  
Gel Filtration ◽  
Transfected Cells ◽  
Linkage Region ◽  
Xylose Residue ◽  
Weak Similarity

2-O-phosphorylation of xylose has been detected in the glycosaminoglycan–protein linkage region, GlcAβ1-3Galβ1-3Galβ1-4Xylβ1-O-Ser, of proteoglycans. Recent mutant analyses in zebrafish suggest that xylosyltransferase I and FAM20B, a protein of unknown function that shows weak similarity to a Golgi kinase encoded by four-jointed, operate in a linear pathway for proteoglycan production. In the present study, we identified FAM20B as a kinase that phosphorylates the xylose residue in the linkage region. Overexpression of FAM20B increased the amount of both chondroitin sulfate and heparan sulfate in HeLa cells, whereas the RNA interference of FAM20B resulted in a reduction of their amount in the cells. Gel-filtration analysis of the glycosaminoglycan chains synthesized in the overexpressing cells revealed that the glycosaminoglycan chains had a similar length to those in mock-transfected cells. These results suggest that FAM20B regulates the number of glycosaminoglycan chains by phosphorylating the xylose residue in the glycosaminoglycan–protein linkage region of proteoglycans.

scholarly journals Inhibition of Bcl-2 expression by a novel tumor-specific RNA interference system increases chemosensitivity to 5-fluorouracil in Hela cells

2006 ◽  
Vol 27 (2) ◽  
pp. 242-248 ◽  
Author(s):  
Sheng-lin HUANG ◽  
Yi WU ◽  
Hai YU ◽  
Ping ZHANG ◽  
Xing-qian ZHANG ◽  
...  
Keyword(s):  
Rna Interference ◽  
Hela Cells ◽  
Interference System

RNA interference targeting CML66, a novel tumor antigen, inhibits proliferation, invasion and metastasis of HeLa cells

2008 ◽  
Vol 269 (1) ◽  
pp. 127-138 ◽  
Author(s):  
Qingfei Wang ◽  
Meixing Li ◽  
Ying Wang ◽  
Yong Zhang ◽  
Shu Jin ◽  
...  
Keyword(s):  
Rna Interference ◽  
Hela Cells ◽  
Tumor Antigen ◽  
Invasion And Metastasis

scholarly journals RNA Interference of Human Papillomavirus Type 18 E6 and E7 Induces Senescence in HeLa Cells

2003 ◽  
Vol 77 (10) ◽  
pp. 6066-6069 ◽  
Author(s):  
Allison H. S. Hall ◽  
Kenneth A. Alexander
Keyword(s):  
Cell Proliferation ◽  
Human Papillomavirus ◽  
Rna Interference ◽  
Hela Cells ◽  
Tumor Suppressors ◽  
Small Interfering Rna ◽  
Promote Cell Proliferation ◽  
E6 And E7 ◽  
Cellular Dna ◽  
Interfering Rna

ABSTRACT The human papillomavirus oncoproteins E6 and E7 promote cell proliferation and contribute to carcinogenesis by interfering with the activities of cellular tumor suppressors. We used a small interfering RNA molecule targeting the E7 region of the bicistronic E6 and E7 mRNA to induce RNA interference, thereby reducing expression of E6 and E7 in HeLa cells. RNA interference of E6 and E7 also inhibited cellular DNA synthesis and induced morphological and biochemical changes characteristic of cellular senescence. These results demonstrate that reducing E6 and E7 expression is sufficient to cause HeLa cells to become senescent.

scholarly journals High Induction of Poly(ADP-ribose) Polymerase Activity in Bleomycin-resistant HeLa Cells

1989 ◽  
Vol 80 (5) ◽  
pp. 464-468 ◽  
Author(s):  
Masahiro Urade ◽  
Masakazu Sugi ◽  
Takashi Mima ◽  
Takafumi Ogura ◽  
Tokuzo Matsuya
Keyword(s):  
Hela Cells ◽  
Polymerase Activity ◽  
High Induction

scholarly journals Phospholipase D2 Is Required for Efficient Endocytic Recycling of Transferrin Receptors

2006 ◽  
Vol 17 (2) ◽  
pp. 598-606 ◽  
Author(s):  
David Padrón ◽  
Renee D. Tall ◽  
Michael G. Roth
Keyword(s):  
Rna Interference ◽  
Hela Cells ◽  
Transferrin Receptors ◽  
Endocytic Recycling ◽  
Recycling Endosomes ◽  
Exchange Factor ◽  
Phospholipase D2 ◽  
Internalization Rate ◽  
Recycling Pathway ◽  
In Cells

RNA interference-mediated depletion of phospholipase D2 (PLD2), but not PLD1, inhibited recycling of transferrin receptors in HeLa cells, whereas the internalization rate was unaffected by depletion of either PLD. Although reduction of both PLD isoforms inhibits PLD activity stimulated by phorbol 12-myristic 13-acetate, only depletion of PLD2 decreased nonstimulated activity. Cells with reduced PLD2 accumulated a greater fraction of transferrin receptors in a perinuclear compartment that was positive for Rab11, a marker of recycling endosomes. EFA6, an exchange factor for Arf6, has been proposed to stimulate the recycling of transferrin receptors. Thus, one consequence of EFA6 overexpression would be a reduction of the internal pool of receptors. We confirmed this observation in control HeLa cells; however, overexpression of EFA6 failed to decrease the internal pool of transferrin receptors that accumulate in cells previously depleted of PLD2. These observations suggest that either PLD2 is required for a constitutive Arf6-mediated recycling pathway or in the absence of PLD2 transferrin receptors accumulate in recycling endosomes that are not responsive to overexpression of EFA6.

Sign in / Sign up

Export Citation Format

Share Document