scholarly journals Characterization of phosphoinositide-specific phospholipase C in rat colonocyte membranes

1993 ◽  
Vol 292 (1) ◽  
pp. 271-276 ◽  
Author(s):  
M J G Bolt ◽  
B M Bissonnette ◽  
R K Wali ◽  
S C Hartmann ◽  
T A Brasitus ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Monoclonal Antibodies ◽  
Phospholipase C ◽  
Plasma Membranes ◽  
Signal Transduction Pathway ◽  
Protein S ◽  
Transduction Pathway ◽  
Intestinal Physiology ◽  
Key Enzyme

The phosphoinositide signal transduction pathway mediates important processes in intestinal physiology, yet the key enzyme, phosphoinositide-specific phospholipase C (PI-PLC), is not well-characterized in the colon. PI-PLC activity was examined in rat colonic membranes using exogenous [3H]phosphatidylinositol 4,5-bisphosphate (PIP2) as substrate, and beta-glycerophosphate to suppress degradation of substrate or product. The activity of membrane PI-PLC increased 6-fold with the addition of alamethicin, and a further 2-3-fold enhancement was observed with 10 microM guanosine 5′-[gamma-thio]triphosphate (GTP[S]), suggesting the involvement of G-protein(s). The effect of GTP[S] appeared to be specific, as up to 100 microM adenosine 5′-[gamma-thio]-triphosphate failed to stimulate PI-PLC activity, and guanosine 5′-[beta-thio]diphosphate inhibited activity. The response of membrane PI-PLC to Ca2+ was biphasic, while > 0.5 mM Mg2+ was inhibitory with or without GTP[S]. Comparable total PI-PLC activities and responses to GTP[S] and Ca2+ were observed in purified brush-border and basolateral membranes. Western immunoblots probed with monoclonal antibodies to PLC isoenzymes PLC-beta 1, -gamma 1 and -delta 1 demonstrated that these antipodal plasma membranes contain predominantly the PLC-delta 1 isoform, with small amounts of PLC-gamma 1 present but no detectable PLC-beta 1. PLC-gamma 1 was the major isoform detected in cytosol.

scholarly journals cAMP activates calcium signalling via phospholipase C to regulate cellulase production in the filamentous fungus Trichoderma reesei

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Yumeng Chen ◽  
Xingjia Fan ◽  
Xinqing Zhao ◽  
Yaling Shen ◽  
Xiangyang Xu ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Phospholipase C ◽  
Trichoderma Reesei ◽  
Filamentous Fungus ◽  
Calcium Signalling ◽  
Signal Transduction Pathway ◽  
Cellulase Production ◽  
Signalling Pathway ◽  
Dependent Manner ◽  
Transduction Pathway

Abstract Background The filamentous fungus Trichoderma reesei is one of the best producers of cellulase and has been widely studied for the production of cellulosic ethanol and bio-based products. We previously reported that Mn2+ and N,N-dimethylformamide (DMF) can stimulate cellulase overexpression via Ca2+ bursts and calcium signalling in T. reesei under cellulase-inducing conditions. To further understand the regulatory networks involved in cellulase overexpression in T. reesei, we characterised the Mn2+/DMF-induced calcium signalling pathway involved in the stimulation of cellulase overexpression. Results We found that Mn2+/DMF stimulation significantly increased the intracellular levels of cAMP in an adenylate cyclase (ACY1)-dependent manner. Deletion of acy1 confirmed that cAMP is crucial for the Mn2+/DMF-stimulated cellulase overexpression in T. reesei. We further revealed that cAMP elevation induces a cytosolic Ca2+ burst, thereby initiating the Ca2+ signal transduction pathway in T. reesei, and that cAMP signalling causes the Ca2+ signalling pathway to regulate cellulase production in T. reesei. Furthermore, using a phospholipase C encoding gene plc-e deletion strain, we showed that the plc-e gene is vital for cellulase overexpression in response to stimulation by both Mn2+ and DMF, and that cAMP induces a Ca2+ burst through PLC-E. Conclusions The findings of this study reveal the presence of a signal transduction pathway in which Mn2+/DMF stimulation produces cAMP. Increase in the levels of cAMP activates the calcium signalling pathway via phospholipase C to regulate cellulase overexpression under cellulase-inducing conditions. These findings provide insights into the molecular mechanism of the cAMP–PLC–calcium signalling pathway underlying cellulase expression in T. reesei and highlight the potential applications of signal transduction in the regulation of gene expression in fungi.

Abstract 741: Characterization of high-grade serous ovarian carcinoma by measuring functional signal transduction pathway activity

2021 ◽  
Author(s):  
Phyllis van der Ploeg ◽  
Laura van Lieshout ◽  
Yvonne Wesseling-Rozendaal ◽  
Anja van de Stolpe ◽  
Diederick Keizer ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Ovarian Carcinoma ◽  
Signal Transduction Pathway ◽  
High Grade ◽  
Transduction Pathway ◽  
Pathway Activity ◽  
Serous Ovarian Carcinoma

scholarly journals Genetic evidence for signal transduction within the Bacillus subtilis GerA germinant receptor

2021 ◽  
Author(s):  
Jeremy D. Amon ◽  
Lior Artzi ◽  
David Z. Rudner
Keyword(s):  
Signal Transduction ◽  
Bacillus Subtilis ◽  
Signal Transduction Pathway ◽  
Dominant Negative ◽  
Transduction Pathway ◽  
Sense And Respond ◽  
Enrichment Strategy ◽  
Functional Receptor

Bacterial spores can rapidly exit dormancy through the process of germination. This process begins with the activation of nutrient receptors embedded in the spore membrane. The prototypical germinant receptor in Bacillus subtilis responds to L-alanine and is thought to be a complex of proteins encoded by the genes in the gerA operon: gerAA , gerAB , and gerAC . The GerAB subunit has recently been shown to function as the nutrient sensor, but beyond contributing to complex stability, no additional functions have been attributed to the other two subunits. Here, we investigate the role of GerAA. We resurrect a previously characterized allele of gerA (termed gerA* ) that carries a mutation in gerAA and show it constitutively activates germination even in the presence of a wild-type copy of gerA . Using an enrichment strategy to screen for suppressors of gerA* , we identified mutations in all three gerA genes that restore a functional receptor. Characterization of two distinct gerAB suppressors revealed that one ( gerAB[E105K]) reduces the GerA complex's ability to respond to L-alanine, while another ( gerAB[F259S] ) disrupts the germinant signal downstream of L-alanine recognition. These data argue against models in which GerAA is directly or indirectly involved in germinant sensing. Rather, our data suggest that GerAA is responsible for transducing the nutrient signal sensed by GerAB. While the steps downstream of gerAA have yet to be uncovered, these results validate the use of a dominant-negative genetic approach in elucidating the gerA signal transduction pathway. Importance Endospore formers are a broad group of bacteria that can enter dormancy upon starvation and exit dormancy upon sensing the return of nutrients. How dormant spores sense and respond to these nutrients is poorly understood. Here, we identify a key step in the signal transduction pathway that is activated after spores detect the amino acid L-alanine. We present a model that provides a more complete picture of this process that is critical for allowing dormant spores to germinate and resume growth.

Characterization of the ABA signal transduction pathway in Vitis vinifera

Plant Science ◽  
2012 ◽  
Vol 187 ◽  
pp. 89-96 ◽  
Author(s):  
Uri Boneh ◽  
Iris Biton ◽  
Amnon Schwartz ◽  
Giora Ben-Ari
Keyword(s):  
Signal Transduction ◽  
Vitis Vinifera ◽  
Signal Transduction Pathway ◽  
Transduction Pathway ◽  
Aba Signal Transduction

scholarly journals A Genetic Analysis of Glucocorticoid Receptor Signaling: Identification and Characterization of Ligand-Effect Modulators in Saccharomyces cerevisiae

Genetics ◽  
2000 ◽  
Vol 156 (3) ◽  
pp. 963-972
Author(s):  
Raquel Sitcheran ◽  
Roger Emter ◽  
Anastasia Kralli ◽  
Keith R Yamamoto
Keyword(s):  
Signal Transduction ◽  
Glucocorticoid Receptor ◽  
Cellular Response ◽  
Transmembrane Protein ◽  
Signal Transduction Pathway ◽  
Transduction Pathway ◽  
Ligand Effect ◽  
Yeast Genetic ◽  
Identification And Characterization

Abstract To find novel components in the glucocorticoid signal transduction pathway, we performed a yeast genetic screen to identify ligand-effect modulators (LEMs), proteins that modulate the cellular response to hormone. We isolated several mutants that conferred increased glucocorticoid receptor (GR) activity in response to dexamethasone and analyzed two of them in detail. These studies identify two genes, LEM3 and LEM4, which correspond to YNL323w and ERG6, respectively. LEM3 is a putative transmembrane protein of unknown function, and ERG6 is a methyltransferase in the ergosterol biosynthetic pathway. Analysis of null mutants indicates that LEM3 and ERG6 act at different steps in the GR signal transduction pathway.

scholarly journals Characterization of a Myeloid Tyrosine Phosphatase, Lyp, and Its Role in the Bcr-Abl Signal Transduction Pathway

2003 ◽  
Vol 278 (30) ◽  
pp. 27413-27420 ◽  
Author(s):  
Wenwen Chien ◽  
Nicola Tidow ◽  
Elizabeth A. Williamson ◽  
Lee-Yung Shih ◽  
Utz Krug ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Tyrosine Phosphatase ◽  
Signal Transduction Pathway ◽  
Transduction Pathway
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