Fluorescent tetradecanoylphorbol acetate: A novel probe of phorbol ester binding domains

1991 ◽  
Vol 46 (3) ◽  
pp. 266-276 ◽  
Author(s):  
Margit Balázs ◽  
Jánòs Szöllösi ◽  
William C. Lee ◽  
Richard P. Haugland ◽  
Anthony P. Guzikowski ◽  
...  
1988 ◽  
Vol 254 (3) ◽  
pp. E358-E364 ◽  
Author(s):  
S. B. Richardson ◽  
S. Twente

In a perifused dispersed rat anterior pituitary cell system, growth hormone (GH) secretion became attenuated in response to repeated pulsatile or prolonged exposure to submaximal stimulatory concentrations of rat growth hormone-releasing factor (GHRF). However, persistent intracellular GH stores could be released upon subsequent challenge with the membrane depolarizing agent KCl, forskolin, or the phorbol ester, tetradecanoylphorbol acetate (TPA). The GH secretory response to repeated pulsatile administration of either KCl or forskolin also became attenuated. In these experiments, persistent intracellular GH stores could be released upon subsequent GHRF stimulation. Repeated challenge with pulses of TPA failed to elicit any GH release after the initial stimulatory response, although a subsequent GHRF pulse was stimulatory, indicating persistence of intracellular GH stores. These data are compatible with the hypothesis that the decreased GH secretory responsivity to GHRF, which was observed in the course of these experiments, is caused by the functional depletion of specific secretagogue-sensitive pools of intracellular GH, rather than by receptor-mediated desensitization.


1986 ◽  
Vol 41 (1-2) ◽  
pp. 94-99 ◽  
Author(s):  
Michael Hebei ◽  
Gerhard Brandner ◽  
Heinz K. Hochkeppel ◽  
Dietmar G. Braun

Abstract 12-O-Tetradecanoylphorbol-13-acetate (TPA, 100 ng ml-1), a tumor promoting phorbol ester, is able to induce enhanced levels of the transformation-associated cellular antigen p53 in normal rat2 cells which had not been previously initiated by a carcinogen. p53 was estimated in ethanolfixed treated cells on microtiter plates with ELISA using the monoclonal antibody Pab 1620 [EMBO J. 7, 1485, (1984)]. Induction of p53 was confirmed by immunoblotting. This effect of TPA is an additional phenotypic characteristic of tumor cells which can be induced by TPA in untransformed rodent cells.


2002 ◽  
Vol 69 ◽  
pp. 59-72 ◽  
Author(s):  
Kurt Drickamer ◽  
Andrew J. Fadden

Many biological effects of complex carbohydrates are mediated by lectins that contain discrete carbohydrate-recognition domains. At least seven structurally distinct families of carbohydrate-recognition domains are found in lectins that are involved in intracellular trafficking, cell adhesion, cell–cell signalling, glycoprotein turnover and innate immunity. Genome-wide analysis of potential carbohydrate-binding domains is now possible. Two classes of intracellular lectins involved in glycoprotein trafficking are present in yeast, model invertebrates and vertebrates, and two other classes are present in vertebrates only. At the cell surface, calcium-dependent (C-type) lectins and galectins are found in model invertebrates and vertebrates, but not in yeast; immunoglobulin superfamily (I-type) lectins are only found in vertebrates. The evolutionary appearance of different classes of sugar-binding protein modules parallels a development towards more complex oligosaccharides that provide increased opportunities for specific recognition phenomena. An overall picture of the lectins present in humans can now be proposed. Based on our knowledge of the structures of several of the C-type carbohydrate-recognition domains, it is possible to suggest ligand-binding activity that may be associated with novel C-type lectin-like domains identified in a systematic screen of the human genome. Further analysis of the sequences of proteins containing these domains can be used as a basis for proposing potential biological functions.


2001 ◽  
Vol 120 (5) ◽  
pp. A528-A528
Author(s):  
S SAKSENA ◽  
R GILL ◽  
S TYAGI ◽  
I SYED ◽  
A CHINNAKOTLA ◽  
...  

1989 ◽  
Vol 61 (01) ◽  
pp. 101-105 ◽  
Author(s):  
Bonnie J Warn-Cramer ◽  
Fanny E Almus ◽  
Samuel I Rapaport

SummaryCultured human umbilical vein endothelial cells (HUVEC) have been reported to produce extrinsic pathway inhibitor (EPI), the factor Xa-dependent inhibitor of factor VHa/tissue factor (TF). We examined the release of this inhibitor from HUVEC as a function of their growth state and in response to the induction of endothelial cell TF activity. HUVEC constitutively produced significant amounts of EPI at all stages of their growth in culture including the post-confluent state. Rate of release varied over a 3-fold range for primary cultures from 12 different batches of pooled umbilical cord cells. Constitutive EPI release was unaltered during a 6 hour period of induction of TF activity with thrombin or phorbol ester but slowed during longer incubation of the cells with phorbol ester. Whereas plasma contains two molecular weight forms of EPI, only the higher of these two molecular weight forms was demonstrable by Western analysis of HUVEC supernatants with 125I-factor Xa as the ligand.


Author(s):  
YuE Kravchenko ◽  
SV Ivanov ◽  
DS Kravchenko ◽  
EI Frolova ◽  
SP Chumakov

Selection of antibodies using phage display involves the preliminary cloning of the repertoire of sequences encoding antigen-binding domains into phagemid, which is considered the bottleneck of the method, limiting the resulting diversity of libraries and leading to the loss of poorly represented variants before the start of the selection procedure. Selection in cell-free conditions using a ribosomal display is devoid from this drawback, however is highly sensitive to PCR artifacts and the RNase contamination. The aim of the study was to test the efficiency of a combination of both methods, including pre-selection in a cell-free system to enrich the source library, followed by cloning and final selection using phage display. This approach may eliminate the shortcomings of each method and increase the efficiency of selection. For selection, alpaca VHH antibody sequences suitable for building an immune library were used due to the lack of VL domains. Analysis of immune libraries from the genes of the VH3, VHH3 and VH4 families showed that the VHH antibodies share in the VH3 and VH4 gene groups is insignificant, and selection from the combined library is less effective than from the VHH3 family of sequences. We found that the combination of ribosomal and phage displays leads to a higher enrichment of high-affinity fragments and avoids the loss of the original diversity during cloning. The combined method allowed us to obtain a greater number of different high-affinity sequences, and all the tested VHH fragments were able to specifically recognize the target, including the total protein extracts of cell cultures.


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