scholarly journals ATP triggers macropinocytosis that internalizes and is regulated by PANX1

2020 ◽  
Author(s):  
Andrew K.J. Boyce ◽  
Emma van der Slagt ◽  
Juan C. Sanchez-Arias ◽  
Leigh Anne Swayne
Keyword(s):  
Neuroblastoma Cells ◽  
Atp Release ◽  
Surface Proteins ◽  
Cell Area ◽  
Release Channel ◽  
Cross Sectional ◽  
Pannexin 1 ◽  
Disease States ◽  
Cellular Area ◽  
Area Expansion

ABSTRACTMacropinocytosis is an endocytic process that allows cells to respond to changes in their environment by internalizing nutrients and cell surface proteins, as well as modulating cell size. Here, we identify that adenosine triphosphate (ATP) triggers macropinocytosis in murine neuroblastoma cells, thereby internalizing the ATP release channel pannexin 1 (PANX1) while concurrently increasing cross-sectional cellular area. Amiloride, a potent inhibitor of macropinocytosis-associated GTPases, abolished ATP-induced PANX1 internalization and cell area expansion. Transient expression of the GTP-hydrolysis resistant GTPase ARF6 Q67L led to increased PANX1 internalization and increased cell area equivalent to levels seen with ATP stimulation. Mutation of an extracellular tryptophan (W74) in PANX1 abolished ATP-evoked cell area enlargement suggesting that PANX1 regulates this form of macropinocytosis. This novel role of PANX1 in macropinocytosis could be particularly important for disease states implicating PANX1, such as cancer, where ATP can act as a purinergic regulator of cell growth/metastasis and as a supplementary energy source following internalization.

scholarly journals Pannexin-1 Deficient Mice Have an Increased Susceptibility for Atrial Fibrillation and Show a QT-Prolongation Phenotype

2016 ◽  
Vol 38 (2) ◽  
pp. 487-501 ◽  
Author(s):  
Stella Petric ◽  
Sofia Klein ◽  
Lisa Dannenberg ◽  
Tillman Lahres ◽  
Lukas Clasen ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Cardiac Electrophysiology ◽  
Electrophysiological Study ◽  
Atp Release ◽  
Release Channel ◽  
Knock Out ◽  
Pannexin 1 ◽  
Significant Prolongation ◽  
Knock Out Mice

Background/Aims: Pannexin-1 (Panx1) is an ATP release channel that is ubiquitously expressed and coupled to several ligand-gated receptors. In isolated cardiac myocytes, Panx1 forms large conductance channels that can be activated by Ca2+ release from the sarcoplasmic reticulum. Here we characterized the electrophysiological function of these channels in the heart in vivo, taking recourse to mice with Panx1 ablation. Methods: Cardiac phenotyping of Panx1 knock-out mice (Panx1-/-) was performed by employing a molecular, cellular and functional approach, including echocardiography, surface and telemetric ECG recordings with QT analysis, physical stress testing and quantification of heart rate variability. In addition, an in vivo electrophysiological study entailed programmed electrical stimulation using an intracardiac octapolar catheter. Results: Panx1 deficiency results in a higher incidence of AV-block, delayed ventricular depolarisation, significant prolongation of QT- and rate corrected QT-interval and a higher incidence of atrial fibrillation after intraatrial burst stimulation. Conclusion: Panx1 seems to play an important role in murine cardiac electrophysiology and warrants further consideration in the context of hereditary forms of atrial fibrillation.

scholarly journals Role of an Aromatic–Aromatic Interaction in the Assembly and Trafficking of the Zebrafish Panx1a Membrane Channel

Biomolecules ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 272 ◽  
Author(s):  
Ksenia Timonina ◽  
Anna Kotova ◽  
Georg Zoidl
Keyword(s):  
Atp Release ◽  
Integral Membrane Protein ◽  
Membrane Channel ◽  
Release Channel ◽  
Post Translational Modifications ◽  
Mutant Proteins ◽  
Pannexin 1 ◽  
Interaction Testing ◽  
Insight Into

Pannexin 1 (Panx1) is a ubiquitously expressed hexameric integral membrane protein known to function as an adenosine triphosphate (ATP) release channel. Panx1 proteins exist in unglycosylated core form (Gly0). They undergo critical post-translational modifications forming the high mannose glycosylation state (Gly1) in the endoplasmic reticulum (ER) and the complex glycosylation state (Gly2) in the Golgi apparatus. The regulation of transition from the ER to the cell membrane is not fully understood. Using site-specific mutagenesis, dye uptake assays, and interaction testing, we identified two conserved aromatic residues, Trp123 and Tyr205, in the transmembrane domains 2 and 3 of the zebrafish panx1a protein. Results suggest that both residues primarily govern the assembly of panx1a subunits into channels, with mutant proteins failing to interact. The results provide insight into a mechanism enabling regulation of Panx1 oligomerization, glycosylation, and trafficking.

scholarly journals Cryo-EM structures of the ATP release channel pannexin 1

2020 ◽  
Vol 27 (4) ◽  
pp. 373-381 ◽  
Author(s):  
Zengqin Deng ◽  
Zhihui He ◽  
Grigory Maksaev ◽  
Ryan M. Bitter ◽  
Michael Rau ◽  
...  
Keyword(s):  
Atp Release ◽  
Release Channel ◽  
Pannexin 1

scholarly journals A permeant regulating its permeation pore: inhibition of pannexin 1 channels by ATP

2009 ◽  
Vol 296 (2) ◽  
pp. C250-C255 ◽  
Author(s):  
Feng Qiu ◽  
Gerhard Dahl
Keyword(s):  
Mutational Analysis ◽  
Rank Order ◽  
Atp Release ◽  
Binding Affinities ◽  
Channel Activity ◽  
Release Channel ◽  
Pannexin 1 ◽  
Atp Inhibition ◽  
Atp Analogues ◽  
Receptor Agonists And Antagonists

Pannexin 1 forms a large membrane channel that, based on its biophysical properties and its expression pattern, is a prime candidate to represent an ATP release channel. Pannexin 1 channel activity is potentially deleterious for cells as indicated by its involvement in the P2X7 death complex. Here we describe a negative feedback loop controlling pannexin 1 channel activity. ATP, permeant to pannexin 1 channels, was found to inhibit its permeation pathway when applied extracellularly to oocytes expressing pannexin 1 exogenously. ATP analogues, including benzoylbenzoyl-ATP, suramin, and brilliant blue G were even more effective inhibitors of pannexin 1 currents than ATP. These compounds also attenuated the uptake of dyes by erythrocytes, which express pannexin 1. The rank order of the compounds in attenuation of pannexin 1 currents was similar to their binding affinities to the P2X7 receptor, except that receptor agonists and antagonists both were inhibitory to the channel. Mutational analysis identified R75 in pannexin 1 to be critical for ATP inhibition of pannexin 1 currents.

scholarly journals Pannexin 1, an ATP Release Channel, Is Activated by Caspase Cleavage of Its Pore-associated C-terminal Autoinhibitory Region

2012 ◽  
Vol 287 (14) ◽  
pp. 11303-11311 ◽  
Author(s):  
Joanna K. Sandilos ◽  
Yu-Hsin Chiu ◽  
Faraaz B. Chekeni ◽  
Allison J. Armstrong ◽  
Scott F. Walk ◽  
...  
Keyword(s):  
Atp Release ◽  
Release Channel ◽  
Caspase Cleavage ◽  
Pannexin 1

scholarly journals Cryo-EM structures of the ATP release channel pannexin 1

2020 ◽  
Author(s):  
Zengqin Deng ◽  
Zhihui He ◽  
Grigory Maksaev ◽  
Ryan M. Bitter ◽  
Michael Rau ◽  
...  
Keyword(s):  
Cancer Progression ◽  
Homo Sapiens ◽  
Apoptotic Cell ◽  
Purinergic Signaling ◽  
Functional Characterization ◽  
Atp Release ◽  
Release Channel ◽  
Pannexin 1 ◽  
Cell Clearance ◽  
Outer Pore

AbstractThe plasma membrane ATP release channel pannexin 1 has been implicated in numerous physiological and pathophysiological processes associated with purinergic signaling, including cancer progression, apoptotic cell clearance, inflammation, blood pressure regulation, oocyte development, epilepsy and neuropathic pain. Here, we present near-atomic resolution structures of Xenopus tropicalis and Homo sapiens PANX1 determined by cryo-electron microscopy that reveal a heptameric channel architecture. Compatible with ATP permeation, the transmembrane pore and cytoplasmic vestibule are exceptionally wide. An extracellular tryptophan ring located at the outer pore creates a constriction site, potentially functioning as a molecular sieve that restricts the size of permeable substrates. In combination with functional characterization, this work elucidates the previously unknown architecture of pannexin channels and establishes a foundation for understanding their unique channel properties as well as for developing rational therapies.

scholarly journals Yeast Morphology Assessment through Automated Image Analysis during Fermentation

Fermentation ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 44
Author(s):  
Mario Guadalupe-Daqui ◽  
Mandi Chen ◽  
Katherine A. Thompson-Witrick ◽  
Andrew J. MacIntosh
Keyword(s):  
Image Analysis ◽  
High Stress ◽  
Cross Sectional Area ◽  
Automated Image Analysis ◽  
Yeast Cells ◽  
Morphological Properties ◽  
Cell Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Industrial Fermentation

The kinetics and success of an industrial fermentation are dependent upon the health of the microorganism(s) responsible. Saccharomyces sp. are the most commonly used organisms in food and beverage production; consequently, many metrics of yeast health and stress have been previously correlated with morphological changes to fermentations kinetics. Many researchers and industries use machine vision to count yeast and assess health through dyes and image analysis. This study assessed known physical differences through automated image analysis taken throughout ongoing high stress fermentations at various temperatures (30 °C and 35 °C). Measured parameters included sugar consumption rate, number of yeast cells in suspension, yeast cross-sectional area, and vacuole cross-sectional area. The cell morphological properties were analyzed automatically using ImageJ software and validated using manual assessment. It was found that there were significant changes in cell area and ratio of vacuole to cell area over the fermentation. These changes were temperature dependent. The changes in morphology have implications for rates of cellular reactions and efficiency within industrial fermentation processes. The use of automated image analysis to quantify these parameters is possible using currently available systems and will provide additional tools to enhance our understanding of the fermentation process.

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