Molecular Recognition of Adenophostin, a Very Potent Ca2+Inducer, at thed-myo-Inositol 1,4,5-Trisphosphate Receptor‡

Biochemistry ◽  
1999 ◽  
Vol 38 (29) ◽  
pp. 9234-9241 ◽  
Author(s):  
Hitoshi Hotoda ◽  
Kazuhiro Murayama ◽  
Shuichi Miyamoto ◽  
Yoriko Iwata ◽  
Masaaki Takahashi ◽  
...  
Keyword(s):  
Molecular Recognition ◽  
Inositol 1,4,5 Trisphosphate ◽  
Adenophostin A ◽  
Trisphosphate Receptor

scholarly journals Ca2+ and calmodulin differentially modulate myo-inositol 1,4,5-trisphosphate (IP3)-binding to the recombinant ligand-binding domains of the various IP3 receptor isoforms

2000 ◽  
Vol 346 (2) ◽  
pp. 275-280 ◽  
Author(s):  
Sara VANLINGEN ◽  
Henk SIPMA ◽  
Patrick DE SMET ◽  
Geert CALLEWAERT ◽  
Ludwig MISSIAEN ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Recombinant Proteins ◽  
Ip3 Receptor ◽  
Binding Characteristics ◽  
Binding Domains ◽  
Receptor Isoforms ◽  
Inositol 1,4,5 Trisphosphate ◽  
Adenophostin A ◽  
Trisphosphate Receptor

We have expressed the N-terminal 581 amino acids of type 1 myo-inositol 1,4,5-trisphosphate receptor (IP3R1), IP3R2 and IP3R3 as recombinant proteins [ligand-binding site 1 (lbs-1), lbs-2, lbs-3] in the soluble fraction of Escherichia coli. These recombinant proteins contain the complete IP3-binding domain and bound IP3 and adenophostin A with high affinity. Ca2+ and calmodulin were previously found to maximally inhibit IP3 binding to lbs-1 by 42±6 and 43±6% respectively, and with an IC50 of approx. 200 nM and 3 μM respectively [Sipma, De Smet, Sienaert, Vanlingen, Missiaen, Parys and De Smedt (1999) J. Biol. Chem. 274, 12157-12562]. We now report that Ca2+ inhibited IP3 binding to lbs-3 with an IC50 of approx. 700 nM (37±4% inhibition at 5 μM Ca2+), while IP3 binding to lbs-2 was not affected by increasing [Ca2+] from 100 nM to 25 μM. Calmodulin (10 μM) inhibited IP3 binding to lbs-3 by 37±4%, while IP3 binding to lbs-2 was inhibited by only 11±2%. The inhibition of IP3 binding to lbs-3 by calmodulin was dose-dependent (IC50≈ 2 μM). We conclude that the IP3-binding domains of the various IP3R isoforms differ in binding characteristics for IP3 and adenophostin A, and are differentially modulated by Ca2+ and calmodulin, suggesting that the various IP3R isoforms can have different intracellular functions.

ChemInform Abstract: Synthesis of Potent Agonists of the D-myo-Inositol 1,4,5-Trisphosphate Receptor Based on Clustered Disaccharide Polyphosphate Analogues of Adenophostin A.

ChemInform ◽  
2000 ◽  
Vol 31 (50) ◽  
pp. no-no
Author(s):  
Martin de Kort ◽  
Vanessa Correa ◽  
A. Rob P. M. Valentijn ◽  
Gijs A. van der Marel ◽  
Barry V. L. Potter ◽  
...  
Keyword(s):  
Inositol 1,4,5 Trisphosphate ◽  
Adenophostin A ◽  
Trisphosphate Receptor

scholarly journals Thimerosal stimulates Ca2+ flux through inositol 1,4,5-trisphosphate receptor type 1, but not type 3, via modulation of an isoform-specific Ca2+-dependent intramolecular interaction

2004 ◽  
Vol 381 (1) ◽  
pp. 87-96 ◽  
Author(s):  
Geert BULTYNCK ◽  
Karolina SZLUFCIK ◽  
Nael Nadif KASRI ◽  
Zerihun ASSEFA ◽  
Geert CALLEWAERT ◽  
...  
Keyword(s):  
Amino Acids ◽  
Conformational Changes ◽  
Intramolecular Interaction ◽  
Binding Activity ◽  
Release Channel ◽  
B Lymphoma Cells ◽  
Inositol 1,4,5 Trisphosphate ◽  
Adenophostin A ◽  
Binding Core ◽  
Trisphosphate Receptor

Thiol-reactive agents such as thimerosal have been shown to modulate the Ca2+-flux properties of IP3 (inositol 1,4,5-trisphosphate) receptor (IP3R) via an as yet unidentified mechanism [Parys, Missiaen, De Smedt, Droogmans and Casteels (1993) Pflügers Arch. 424, 516–522; Kaplin, Ferris, Voglmaier and Snyder (1994) J. Biol. Chem. 269, 28972–28978; Missiaen, Taylor and Berridge (1992) J. Physiol. (Cambridge, U.K.) 455, 623–640; Missiaen, Parys, Sienaert, Maes, Kunzelmann, Takahashi, Tanzawa and De Smedt (1998) J. Biol. Chem. 273, 8983–8986]. In the present study, we show that thimerosal potentiated IICR (IP3-induced Ca2+ release) and IP3-binding activity of IP3R1, expressed in triple IP3R-knockout R23-11 cells derived from DT40 chicken B lymphoma cells, but not of IP3R3 or [Δ1–225]-IP3R1, which lacks the N-terminal suppressor domain. Using a 45Ca2+-flux technique in permeabilized A7r5 smooth-muscle cells, we have shown that Ca2+ shifted the stimulatory effect of thimerosal on IICR to lower concentrations of thimerosal and thereby increased the extent of Ca2+ release. This suggests that Ca2+ and thimerosal synergetically regulate IP3R1. Glutathione S-transferase pull-down experiments elucidated an interaction between amino acids 1–225 (suppressor domain) and amino acids 226–604 (IP3-binding core) of IP3R1, and this interaction was strengthened by both Ca2+ and thimerosal. In contrast, calmodulin and sCaBP-1 (short Ca2+-binding protein-1), both having binding sites in the 1–225 region, weakened the interaction. This interaction was not found for IP3R3, in agreement with the lack of functional stimulation of this isoform by thimerosal. The interaction between the IP3-binding and transmembrane domains (amino acids 1–604 and 2170–2749 respectively) was not affected by thimerosal and Ca2+, but it was significantly inhibited by IP3 and adenophostin A. Our results demonstrate that thimerosal and Ca2+ induce isoform-specific conformational changes in the N-terminal part of IP3R1, leading to the formation of a highly IP3-sensitive Ca2+-release channel.

Synthesis of Potent Agonists of thed-myo-Inositol 1,4,5-Trisphosphate Receptor Based on Clustered Disaccharide Polyphosphate Analogues of Adenophostin A

2000 ◽  
Vol 43 (17) ◽  
pp. 3295-3303 ◽  
Author(s):  
Martin de Kort ◽  
Vanessa Correa ◽  
A. Rob P. M. Valentijn ◽  
Gijs A. van der Marel ◽  
Barry V. L. Potter ◽  
...  
Keyword(s):  
Inositol 1,4,5 Trisphosphate ◽  
Adenophostin A ◽  
Trisphosphate Receptor
Sign in / Sign up

Export Citation Format

Share Document