Mammalian Notch receptors contain 29-36 epidermal growth factor (EGF)-like repeats that may be modified by protein O-fucosyltransferase 1 (Pofut1), an essential component of the canonical Notch signaling pathway. The Drosophila orthologue Ofut1 is proposed to function as both a chaperone required for stable cell surface expression of Notch and a protein O-fucosyltransferase. Here we investigate...

Human Toll like receptor (TLR) 2 has been implicated as a signaling receptor for LPS from Gram-negative bacteria and cell wall components from Gram-positive organisms. In this study, we investigated whether TLR2 can signal cell activation by the heat-killed group B streptococci type III (GBS) and Listeria monocytogenes (HKLM). HKLM, but not GBS, showed a time- and dose-dependent activation of C...

OBJECTIVE To define the ability of GPIHBP1 to bind other lipase family members and other apolipoproteins (apos) and lipoproteins. METHODS AND RESULTS GPIHBP1, a GPI-anchored lymphocyte antigen (Ly)6 protein of capillary endothelial cells, binds lipoprotein lipase (LPL) avidly, but its ability to bind related lipase family members has never been evaluated. As judged by cell-based and cell-free...

In an effort to shed light upon the processes of antitumor drug-induced cell death, we have carried out a systemic study of the effects of the anti-topoisomerase II agent, etoposide, on Chinese hamster ovary cells. Treatment of Chinese hamster ovary cells for 1 h with a 2-log cell-killing concentration of etoposide induces a high incidence of DNA single-strand breaks which are rapidly repaired ...

The intracellular concentrations of polyphosphoinositides and inositol phosphates were determined, and their role in growth factor-initiated cell division was investigated in a Chinese hamster ovary cell inositol auxotroph (CHO-K1-Ins). Metabolic labeling experiments during inositol starvation of CHO-K1-Ins cells showed that 1) the lipid-linked inositol component was maintained at the expense o...

Single-stranded reovirus RNA, synthesized in vitro by reovirus cores, functioned as messenger RNA in cell-free extracts prepared from several mammalian cells: Krebs II mouse ascites cells, mouse L cells, Chinese hamster ovary cells, HeLa cells, and rabbit reticulocytes. As shown by acrylamide gel electrophoresis, all eight polypeptides known to be specified by reovirus were synthesized in the r...

The potent tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) was tested for its ability (a) to induce sister chromatid exchange, (b) to increase the rate of transition at the adenine phosphoribosyltransferase (apt) locus from the presumptive heterozygous state ((+/- to the homozygous state (-/ - or -), and (c) to enhance the frequency of mutations expressed after ultraviolet radiation m...

The amount of crude Campylobacter jejuni enterotoxin present in culture products was quantitated by comparing the response of these preparations with that of pure Escherichia coli heat-labile toxin (LT) in the Chinese hamster ovary assay and in enzyme-linked immunosorbent assays that used GM ganglioside or antisera to LT or both. Maximum C. jejuni enterotoxin production was achieved by growth a...

Mitomycin C is an alkylating agent used in cancer chemotherapy that shows some specificity towards hypoxic cells. The therapeutic effects of this compound are thought to result from its metabolic activation by enzymes such as NADPH:cytochrome P-450 reductase. In a previous report we described a Chinese hamster ovary cell line resistant to mitomycin C, which had a decreased NADPH:cytochrome P-45...

Introduction Leukemia inhibitory factor (LIF) is a polyfunctional cytokine with numerous regulatory effects in vivo and in vitro. In murine stem cell cultures it is the essential media supplement for the maintenance of pluripotency of embryonic and induced pluripotent stem cells. To explore if the glycosylation and/or other post-translational modifications are affecting this activity, we produc...