scholarly journals Exploration of inositol 1,4,5-trisphosphate (IP3) regulated dynamics of N-terminal domain of IP3 receptor reveals early phase molecular events during receptor activation

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Aneesh Chandran ◽  
Xavier Chee ◽  
David L. Prole ◽  
Taufiq Rahman
Keyword(s):  
Early Phase ◽  
Receptor Activation ◽  
Ip3 Receptor ◽  
Terminal Domain ◽  
Molecular Events ◽  
Inositol 1,4,5 Trisphosphate

scholarly journals Exploration of inositol 1,4,5-trisphosphate (IP3) regulated dynamics of N-terminal domain of IP3 receptor reveals early phase molecular events during receptor activation

2018 ◽  
Author(s):  
Aneesh Chandran ◽  
Xavier Chee ◽  
David L. Prole ◽  
Taufiq Rahman
Keyword(s):  
Conformational Dynamics ◽  
Md Simulations ◽  
Receptor Activation ◽  
Activation Mechanism ◽  
Ip3 Receptor ◽  
Dynamic Correlation ◽  
Molecular Events ◽  
Binding Core ◽  
Domain Dynamics ◽  
Phosphate Groups

Inositol 1, 4, 5-trisphosphate (IP3) binding at the N-terminus (NT) of IP3 receptor (IP3R) allosterically triggers the opening of a Ca2+-conducting pore located ~ 100 Å away from the IP3-binding core (IBC). However, the precise mechanism of IP3 binding and correlated domain dynamics in the NT that are central to the IP3R activation, remains unknown. Our all-atom molecular dynamics (MD) simulations recapitulate the characteristic twist motion of the suppresser domain (SD) and reveal correlated ‘clam closure’ dynamics of IBC with IP3-binding, complementing existing suggestions on IP3R activation mechanism. Our study further reveals the existence of inter-domain dynamic correlation in the NT and establishes the SD to be critical for the conformational dynamics of IBC. Also, a tripartite interaction involving Glu283-Arg54-Asp444 at the SD – IBC interface seemed critical for IP3R activation. Intriguingly, during the sub-microsecond long simulation, we observed Arg269 undergoing an SD-dependent flipping of hydrogen bonding between the first and fifth phosphate groups of IP3. This seems to play a major role in determining the IP3 binding affinity of IBC in the presence/absence of the SD. Our study thus provides atomistic details of early molecular events occurring within the NT during and following IP3 binding that lead to channel gating.

Inhibition of TASK-1 potassium channel by phospholipase C

2001 ◽  
Vol 281 (2) ◽  
pp. C700-C708 ◽  
Author(s):  
Gábor Czirják ◽  
Gábor L. Petheő ◽  
András Spät ◽  
Péter Enyedi
Keyword(s):  
Phospholipase C ◽  
Lysophosphatidic Acid ◽  
Protein S ◽  
Receptor Activation ◽  
Xenopus Laevis Oocytes ◽  
Ang Ii ◽  
Inositol 1,4,5 Trisphosphate ◽  
Glomerulosa Cells ◽  
Pore Domain ◽  
Stimulation Of

The two-pore-domain K+ channel, TASK-1, was recently shown to be a target of receptor-mediated regulation in neurons and in adrenal glomerulosa cells. Here, we demonstrate that TASK-1 expressed in Xenopus laevis oocytes is inhibited by different Ca2+-mobilizing agonists. Lysophosphatidic acid, via its endogenous receptor, and ANG II and carbachol, via their heterologously expressed ANG II type 1a and M1 muscarinic receptors, respectively, inhibit TASK-1. This effect can be mimicked by guanosine 5′- O-(3-thiotriphosphate), indicating the involvement of GTP-binding protein(s). The phospholipase C inhibitor U-73122 reduced the receptor-mediated inhibition of TASK-1. Downstream signals of phospholipase C action (inositol 1,4,5-trisphosphate, cytoplasmic Ca2+ concentration, and diacylglycerol) do not mediate the inhibition. Unlike the Gq-coupled receptors, stimulation of the Gi-activating M2 muscarinic receptor coexpressed with TASK-1 results in an only minimal decrease of the TASK-1 current. However, additional coexpression of phospholipase C-β2 (which is responsive also to Giβγ-subunits) renders M2 receptor activation effective. This indicates the significance of phospholipase C activity in the receptor-mediated inhibition of TASK-1.

scholarly journals In vivo Stimulus-Induced Vasodilation Occurs without IP3 Receptor Activation and May Precede Astrocytic Calcium Increase

2013 ◽  
Vol 33 (19) ◽  
pp. 8411-8422 ◽  
Author(s):  
K. Nizar ◽  
H. Uhlirova ◽  
P. Tian ◽  
P. A. Saisan ◽  
Q. Cheng ◽  
...  
Keyword(s):  
Receptor Activation ◽  
Ip3 Receptor

The existence of inositol 1,4,5-trisphosphate and ryanodine receptors in mature bovine oocytes

Development ◽  
1995 ◽  
Vol 121 (8) ◽  
pp. 2645-2654 ◽  
Author(s):  
C. Yue ◽  
K.L. White ◽  
W.A. Reed ◽  
T.D. Bunch
Keyword(s):  
Ryanodine Receptors ◽  
Inhibitory Effect ◽  
Ruthenium Red ◽  
Calcium Oscillations ◽  
Ip3 Receptor ◽  
Cyclic Adp Ribose ◽  
Inositol 1,4,5 Trisphosphate ◽  
Bovine Oocytes ◽  
Continuous Injection

Intracellular Ca2+ (Ca2+i) transients during fertilization are critical to the activation of eggs in all species studied. Activation of both the inositol 1,4,5-trisphosphate (IP3) receptor (IP3R) and ryanodine receptor (RYR) are responsible for the calcium oscillations during fertilization in sea urchin eggs. Using in vitro matured bovine oocytes loaded with Fura-2 AM ester as Ca2+i indicator, we addressed whether IP3Rs and RYRs coexist in mammalian eggs. Our results indicate that microinjection of 50–250 nM IP3 or 10–20 mM caffeine, 100–200 microM ryanodine and 4–8 microM cyclic ADP-ribose all induced Ca2+i release. The Ca2+i release induced by 250 nM IP3 could only be inhibited by prior injection of 1 mg/ml heparin which was overcome by continuous injection of IP3 to 1 microM. Prior injection of either 50 microM ruthenium red, 50 microM procaine or 1 % vehicle medium (VM) did not affect the Ca2+i release induced by IP3. Prior injection of heparin or VM did not affect the Ca2+i release induced by 10–20 mM caffeine or 200 microM ryanodine, but prior injection of 50 microM ruthenium red or procaine completely inhibited the effect of 10–20 mM caffeine. In addition, continuous injection of caffeine up to 40 mM overcame the inhibitory effect of ruthenium red or procaine. The same 50 microM concentration of ruthenium red or procaine only partially blocked the effect of 200 microM ryanodine, but 200 microM ruthenium red or procaine completely blocked the effect of 200 microM ryanodine.(ABSTRACT TRUNCATED AT 250 WORDS)

Mobilization of Intracellular Calcium by Methacholine and Inositol 1,4,5-Trisphosphate in Rat Parotid Acinar Cells

1987 ◽  
Vol 66 (2) ◽  
pp. 547-551 ◽  
Author(s):  
D.L. Aub ◽  
J.W. Putney
Keyword(s):  
Receptor Activation ◽  
Transient Phase ◽  
Cell Preparation ◽  
Similar Concentration ◽  
Parotid Acinar Cells ◽  
Parotid Acinar Cell ◽  
Inositol 1,4,5 Trisphosphate ◽  
Intracellular Ca ◽  
Rat Parotid ◽  
Stimulation Of

In the rat parotid acinar cell, methacholine caused an increase in [Ca2+]i as determined by quin-2 fluorescence. The increase in [Ca2+] i was initially independent of, and subsequently dependent on, the presence of extracellular Ca2+, indicating mobilization of intracellular Ca2+, as well as activation of Ca2+ entry. Methacholine mobilization of the internal Ca2+ pool and stimulation of the initial transient phase of K+ efflux have similar concentration dependencies; the EC50 value for Ca2+ mobilization is 80 nmollL, the EC50 value for K+ efflux is 200 nmol/L. In a permeable parotid cell preparation, inositol 1,4,5-trisphosphate, inositol 2,4,5-trisphosphate, and inositol 4,5-bisphosphate were able to release Ca2+ from an ATP-dependent, oligomycininsensitive pool. These observations, when taken with the previous finding that methacholine stimulates Ca-independent inositol trisphosphate formation, support the view that inositol 1,4,5-trisphosphate acts as a second messenger mediating the release of an intracellular Ca 2+ pool following muscarinic receptor activation in the parotid gland.

Partial calcium release in response to submaximal inositol 1,4,5-trisphosphate receptor activation

1994 ◽  
Vol 98 (2) ◽  
pp. 147-156 ◽  
Author(s):  
Ludwig Missiaen ◽  
Jan B. Parys ◽  
Humbert De Smedt ◽  
Masahiro Oike ◽  
Rik Casteels
Keyword(s):  
Calcium Release ◽  
Receptor Activation ◽  
Inositol 1,4,5 Trisphosphate ◽  
Trisphosphate Receptor

Structure of the N-terminal domain of Euprosthenops australis dragline silk suggests that conversion of spidroin dope to spider silk involves a conserved asymmetric dimer intermediate

2019 ◽  
Vol 75 (7) ◽  
pp. 618-627 ◽  
Author(s):  
Wangshu Jiang ◽  
Glareh Askarieh ◽  
Alexander Shkumatov ◽  
My Hedhammar ◽  
Stefan D. Knight
Keyword(s):  
Electrostatic Interactions ◽  
Spider Silk ◽  
Quaternary Structure ◽  
Nephila Clavipes ◽  
Trigger Mechanism ◽  
Dragline Silk ◽  
Terminal Domain ◽  
Structure Changes ◽  
Molecular Events ◽  
Asymmetric Dimer

Spider silk is a biomaterial with exceptional mechanical toughness, and there is great interest in developing biomimetic methods to produce engineered spider silk-based materials. However, the mechanisms that regulate the conversion of spider silk proteins (spidroins) from highly soluble dope into silk are not completely understood. The N-terminal domain (NT) of Euprosthenops australis dragline silk protein undergoes conformational and quaternary-structure changes from a monomer at a pH above 7 to a homodimer at lower pH values. Conversion from the monomer to the dimer requires the protonation of three conserved glutamic acid residues, resulting in a low-pH `locked' dimer stabilized by symmetric electrostatic interactions at the poles of the dimer. The detailed molecular events during this transition are still unresolved. Here, a 2.1 Å resolution crystal structure of an NT T61A mutant in an alternative, asymmetric, dimer form in which the electrostatic interactions at one of the poles are dramatically different from those in symmetrical dimers is presented. A similar asymmetric dimer structure from dragline silk of Nephila clavipes has previously been described. It is suggested that asymmetric dimers represent a conserved intermediate state in spider silk formation, and a revised `lock-and-trigger' mechanism for spider silk formation is presented.

scholarly journals Inositol 1,4,5-trisphosphate–induced Calcium Release Is Necessary for Generating the Entire Light Response of Limulus Ventral Photoreceptors

2003 ◽  
Vol 121 (5) ◽  
pp. 441-449 ◽  
Author(s):  
Alan Fein
Keyword(s):  
Calcium Release ◽  
Cyclopiazonic Acid ◽  
Light Response ◽  
Calcium Stores ◽  
Ip3 Receptor ◽  
Treatment Results ◽  
Light Responses ◽  
Calcium Buffer ◽  
Pressure Injection ◽  
Inositol 1,4,5 Trisphosphate

The experiments reported here were designed to answer the question of whether inositol 1,4,5-trisphosphate (IP3)-induced calcium release is necessary for generating the entire light response of Limulus ventral photoreceptors. For this purpose the membrane-permeable IP3 receptor antagonist 2-aminoethoxydiphenyl borate (2APB) (Maruyama, T., T. Kanaji, S. Nakade, T. Kanno, and K. Mikoshiba. 1997. J. Biochem. (Tokyo). 122:498–505) was used. Previously, 2APB was found to inhibit the light activated current of Limulus ventral photoreceptors and reversibly inhibit both light and IP3 induced calcium release as well as the current activated by pressure injection of calcium into the light sensitive lobe of the photoreceptor (Wang, Y., M. Deshpande, and R. Payne. 2002. Cell Calcium. 32:209). In this study 2APB was found to inhibit the response to a flash of light at all light intensities and to inhibit the entire light response to a step of light, that is, both the initial transient and the steady-state components of the response to a step of light were inhibited. The light response in cells injected with the calcium buffer 1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (BAPTA) was reversibly inhibited by 2APB, indicating that these light responses result from IP3-mediated calcium release giving rise to an increase in Cai. The light response obtained from cells after treatment with 100 μM cyclopiazonic acid (CPA), which acts to empty intracellular calcium stores, was reversibly inhibited by 2APB, indicating that the light response after CPA treatment results from IP3-mediated calcium release and a consequent rise in Cai. Together these findings imply that IP3-induced calcium release is necessary for generating the entire light response of Limulus ventral photoreceptors.

Characterization and mapping of the 12kDa FK506-binding protein (FKBP12)-binding site on different isoforms of the ryanodine receptor and of the inositol 1,4,5-trisphosphate receptor

2001 ◽  
Vol 354 (2) ◽  
pp. 413-422 ◽  
Author(s):  
Geert BULTYNCK ◽  
Patrick DE SMET ◽  
Daniela ROSSI ◽  
Geert CALLEWAERT ◽  
Ludwig MISSIAEN ◽  
...  
Keyword(s):  
Binding Site ◽  
Ryanodine Receptor ◽  
Binding Protein ◽  
Limited Proteolysis ◽  
Ip3 Receptor ◽  
Fk506 Binding Protein ◽  
High Affinity ◽  
Receptor Isoforms ◽  
Inositol 1,4,5 Trisphosphate ◽  
Affinity Interaction

We investigated the interaction of the 12kDa FK506-binding protein (FKBP12) with two ryanodine-receptor isoforms (RyR1 and RyR3) and with two myo-inositol 1,4,5-trisphosphate (IP3) receptor isoforms (IP3R1 and IP3R3). Using glutathione S-transferase (GST)-FKBP12 affinity chromatography, we could efficiently extract RyR1 (42±7% of the solubilized RyR1) from terminal cisternae of skeletal muscle as well as RyR3 (32±4% of the solubilized RyR3) from RyR3-overexpressing HEK-293 cells. These interactions were completely abolished by FK506 (20µM) but were largely unaffected by RyR-channel modulators. In contrast, neither IP3R1 nor IP3R3 from various sources, including rabbit cerebellum, A7r5 smooth-muscle cells and IP3R-overexpressing Sf9 insect cells from Spodoptera frugiperda, were retained on the GST-FKBP12 matrix. Moreover, immunoprecipitation experiments indicated a high-affinity interaction of FKBP12 with RyR1 but not with IP3R1. In order to determine the FKBP12-binding site, we fragmented both RyR1 and IP3R1 by limited proteolysis. We obtained a 45kDa fragment of RyR1 that bound to the GST-FKBP12 matrix, indicating that it retained all requirements for FKBP12 binding. This fragment was identified by its interaction with antibody m34C and must therefore contain its epitope (amino acids 2756–2803). However, no fragment of IP3R1 was retained on the column. These molecular data are in agreement with the lack of correlation between FKBP12 and IP3R1 expression in various cell types. The observation that FKBP12 did not affect IP3-induced Ca2+ release but reduced caffeine-induced Ca2+ release also indicated that mature IP3R1 and IP3R3, in contrast to RyR1 and RyR3, did not display a specific, high-affinity interaction with FKBP12.

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