A Change in Intracellular pH does not Contribute to the Signal Transduction Chain in Phytochrome-Mediated Spore Germination

1986 ◽  
pp. 393-393
Author(s):  
Randy Wayne ◽  
Peter K. Hepler
Keyword(s):  
Signal Transduction ◽  
Intracellular Ph ◽  
Spore Germination

Intracellular alkalinization augments capacitative Ca2+ entry in platelets

2003 ◽  
Vol 90 (12) ◽  
pp. 1121-1127 ◽  
Author(s):  
Mikio Marumo ◽  
Ichiro Wakabayashi
Keyword(s):  
Signal Transduction ◽  
Platelet Aggregation ◽  
Intracellular Ph ◽  
Free Medium ◽  
Intracellular Acidification ◽  
Excitable Cells ◽  
Simultaneous Addition ◽  
Intracellular Alkalinization

SummaryIn order to elucidate the significance of intracellular alkalinization in signal transduction of platelets, we investigated the effects on capacitative Ca2+ entry (CCE) of intracellular alkalinization that was induced by NH4Cl. Addition of NH4Cl (10 mM) to the medium resulted in an elevation of intracellular pH by about 0.35, which was eliminated by simultaneous addition of propionate (20 mM), an inducer of intracellular acidification, to the medium. CCE was induced by an extracellular addition of Ca2+ to platelets in which Ca2+ stores had been depleted by stimulation with thapsigargin in nominally Ca2+-free medium. NH4Cl markedly augmented CCE and subsequent platelet aggregation, both of which were abolished in the presence of SKF-96365, an inhibitor of capacitative Ca2+ entry in non-excitable cells such as platelets. The augmentation of CCE and subsequent aggregation by NH4Cl was not observed in the presence of propionate or SKF-96365. Extracellular alkalosis induced by Tris also markedly augmented CCE and subsequent aggregation. These augmenting effects of extracellular alkalosis by Tris were significantly but incompletely inhibited by simultaneous addition of propionate (20 mM), which completely eliminated elevation of intracellular pH elicited by Tris. Thus, the augmenting effect of extracellular alkalosis on CCE was in part mediated by intracellular alkalosis. These findings suggest that intracellular alkalinization is a potent signal that augments CCE in platelets.

Genetic suppression meets structure prediction: probing a spore germination receptor complex

2021 ◽  
Author(s):  
Anne Moir ◽  
David Popham
Keyword(s):  
Signal Transduction ◽  
Spore Germination ◽  
Structure Prediction ◽  
Receptor Complex ◽  
Genetic Approach ◽  
Classical Genetic ◽  
Genetic Suppression

Despite the thousands of spore germinant receptor operons identified in genomes of Bacilli and Clostridia, understanding how the three essential receptor components act as a signal transduction machine in germination remains limited. The paper by Amon et al in this issue uses the classical genetic approach of suppression to define a region of likely interaction between the GerAA and GerAB proteins: it provides a first glimpse into potential events within the receptor complex.

scholarly journals Influence of CO2pneumoperitoneum on intracellular pH and signal transduction in cancer cells

2005 ◽  
Vol 6B (7) ◽  
pp. 650-655 ◽  
Author(s):  
Li-ping Cao ◽  
Guo-ping Ding ◽  
Ri-sheng Que ◽  
Shu Zheng
Keyword(s):  
Signal Transduction ◽  
Cancer Cells ◽  
Intracellular Ph

Intracellular pH does not change during phytochrome-mediated spore germination in Onoclea

1986 ◽  
Vol 113 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Randy Wayne ◽  
David Rice ◽  
Peter K. Hepler
Keyword(s):  
Intracellular Ph ◽  
Spore Germination

scholarly journals Cooperativity Between Different Nutrient Receptors in Germination of Spores of Bacillus subtilis and Reduction of This Cooperativity by Alterations in the GerB Receptor

2006 ◽  
Vol 188 (1) ◽  
pp. 28-36 ◽  
Author(s):  
Swaroopa Atluri ◽  
Katerina Ragkousi ◽  
Donna E. Cortezzo ◽  
Peter Setlow
Keyword(s):  
Signal Transduction ◽  
Amino Acids ◽  
Bacillus Subtilis ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Binding Site ◽  
Spore Germination ◽  
Binding Sites ◽  
Signal Transduction Pathways ◽  
Amino Acid Binding

ABSTRACT The GerA nutrient receptor alone triggers germination of Bacillus subtilis spores with l-alanine or l-valine, and these germinations were stimulated by glucose and K+ plus the GerK nutrient receptor. The GerB nutrient receptor alone did not trigger spore germination with any nutrients but required glucose, fructose, and K+ (GFK) (termed cogerminants) plus GerK for triggering of germination with a number of l-amino acids. GerB and GerA also triggered spore germination cooperatively with l-asparagine, fructose, and K+ and either l-alanine or l-valine. Two GerB variants (termed GerB*s) that were previously isolated by their ability to trigger spore germination in response to d-alanine do not respond to d-alanine but respond to the same l-amino acids that stimulate germination via GerB plus GerK and GFK. GerB*s alone triggered spore germination with these l-amino acids, although GerK plus GFK stimulated the rates of these germinations. In contrast to l-alanine germination via GerA, spore germination via l-alanine and GerB or GerB* was not inhibited by d-alanine. These data support the following conclusions. (i) Interaction with GerK, glucose, and K+ somehow stimulates spore germination via GerA. (ii) GerB can bind and respond to l-amino acids, although normally either the binding site is inaccessible or its occupation is not sufficient to trigger spore germination. (iii) Interaction of GerB with GerK and GFK allows GerB to bind or respond to amino acids. (iv) In addition to spore germination due to the interaction between GerA and GerK, and GerB and GerK, GerB can interact with GerA to trigger spore germination in response to appropriate nutrients. (v) The amino acid sequence changes in GerB*s reduce these receptor variants' requirement for GerK and cogerminants in their response to l-amino acids. (vi) GerK binds glucose, GerB interacts with fructose in addition to l-amino acids, and GerA interacts only with l-valine, l-alanine, and its analogs. (vii) The amino acid binding sites in GerA and GerB are different, even though both respond to l-alanine. These new conclusions are integrated into models for the signal transduction pathways that initiate spore germination.

Ultrastructural aspects of olfactory signal transduction and its development

1994 ◽  
Vol 52 ◽  
pp. 142-143
Author(s):  
Bert Ph. M. Menco
Keyword(s):  
Signal Transduction ◽  
Olfactory Receptor ◽  
Receptor Cell ◽  
Freeze Substitution ◽  
Luminal Surface ◽  
Tissue Sections ◽  
Olfactory Receptor Cells ◽  
Receptor Cells ◽  
Olfactory Signal ◽  
Odor Molecule

Vertebrate olfactory receptor cells are specialized neurons that have numerous long tapering cilia. The distal parts of these cilia line the interface between the external odorous environment and the luminal surface of the olfactory epithelium. The length and number of these cilia results in a large surface area that presumably increases the chance that an odor molecule will meet a receptor cell. Advanced methods of cryoprepration and immuno-gold labeling were particularly useful to preserve the delicate ultrastructural and immunocytochemical features of olfactory cilia required for localization of molecules involved in olfactory signal-transduction. We subjected olfactory tissues to freeze-substitution in acetone (unfixed tissues) or methanol (fixed tissues) followed by low temperature embedding in Lowicryl K11M for that purpose. Tissue sections were immunoreacted with several antibodies against proteins that are presumably important in olfactory signal-transduction.

Signal-regulated oxidation of proteins via MICAL

2020 ◽  
Vol 48 (2) ◽  
pp. 613-620
Author(s):  
Clara Ortegón Salas ◽  
Katharina Schneider ◽  
Christopher Horst Lillig ◽  
Manuela Gellert
Keyword(s):  
Signal Transduction ◽  
Hydrogen Peroxide ◽  
Cell Death ◽  
Redox Regulation ◽  
Signal Transduction Pathways ◽  
Cellular Functions ◽  
Intracellular Signals ◽  
Amino Acid Side Chains ◽  
Specific Receptors ◽  
Sulfur Containing

Processing of and responding to various signals is an essential cellular function that influences survival, homeostasis, development, and cell death. Extra- or intracellular signals are perceived via specific receptors and transduced in a particular signalling pathway that results in a precise response. Reversible post-translational redox modifications of cysteinyl and methionyl residues have been characterised in countless signal transduction pathways. Due to the low reactivity of most sulfur-containing amino acid side chains with hydrogen peroxide, for instance, and also to ensure specificity, redox signalling requires catalysis, just like phosphorylation signalling requires kinases and phosphatases. While reducing enzymes of both cysteinyl- and methionyl-derivates have been characterised in great detail before, the discovery and characterisation of MICAL proteins evinced the first examples of specific oxidases in signal transduction. This article provides an overview of the functions of MICAL proteins in the redox regulation of cellular functions.

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