Inositol 1,4,5-trisphosphate Receptor Contains Multiple Cavities and L-shaped Ligand-binding Domains

2004 ◽  
Vol 336 (1) ◽  
pp. 155-164 ◽  
Author(s):  
Chikara Sato ◽  
Kozo Hamada ◽  
Toshihiko Ogura ◽  
Atsuo Miyazawa ◽  
Kenji Iwasaki ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Binding Domains ◽  
Inositol 1,4,5 Trisphosphate ◽  
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.

scholarly journals Cooperative Formation of the Ligand-binding Site of the Inositol 1,4,5-Trisphosphate Receptor by Two Separable Domains

1999 ◽  
Vol 274 (1) ◽  
pp. 328-334 ◽  
Author(s):  
Fumio Yoshikawa ◽  
Hirohide Iwasaki ◽  
Takayuki Michikawa ◽  
Teiichi Furuichi ◽  
Katsuhiko Mikoshiba
Keyword(s):  
Ligand Binding ◽  
Binding Site ◽  
Ligand Binding Site ◽  
Inositol 1,4,5 Trisphosphate ◽  
Trisphosphate Receptor

scholarly journals The regulatory domain of the inositol 1,4,5-trisphosphate receptor is necessary to keep the channel domain closed: possible physiological significance of specific cleavage by caspase 3

2004 ◽  
Vol 377 (2) ◽  
pp. 299-307 ◽  
Author(s):  
Tomohiro NAKAYAMA ◽  
Mitsuharu HATTORI ◽  
Keiko UCHIDA ◽  
Takeshi NAKAMURA ◽  
Yoko TATEISHI ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Caspase 3 ◽  
Fluorescent Protein ◽  
Binding Domain ◽  
Ligand Binding Domain ◽  
Physiological Significance ◽  
Regulatory Domain ◽  
Inositol 1,4,5 Trisphosphate ◽  
Trisphosphate Receptor ◽  
In Cells

The type 1 inositol 1,4,5-trisphosphate receptor (IP3R1) is an intracellular Ca2+ channel protein that plays crucial roles in generating complex Ca2+ signalling patterns. IP3R1 consists of three domains: a ligand-binding domain, a regulatory domain and a channel domain. In order to investigate the function of these domains in its gating machinery and the physiological significance of specific cleavage by caspase 3 that is observed in cells undergoing apoptosis, we utilized various IP3R1 constructs tagged with green fluorescent protein (GFP). Expression of GFP-tagged full-length IP3R1 or IP3R1 lacking the ligand-binding domain in HeLa and COS-7 cells had little effect on cells’ responsiveness to an IP3-generating agonist ATP and Ca2+ leak induced by thapsigargin. On the other hand, in cells expressing the caspase-3-cleaved form (GFP–IP3R1-casp) or the channel domain alone (GFP–IP3R1-ES), both ATP and thapsigargin failed to induce increase of cytosolic Ca2+ concentration. Interestingly, store-operated (−like) Ca2+ entry was normally observed in these cells, irrespective of thapsigargin pre-treatment. These findings indicate that the Ca2+ stores of cells expressing GFP–IP3R1-casp or GFP–IP3R1-ES are nearly empty in the resting state and that these proteins continuously leak Ca2+. We therefore propose that the channel domain of IP3R1 tends to remain open and that the large regulatory domain of IP3R1 is necessary to keep the channel domain closed. Thus cleavage of IP3R1 by caspase 3 may contribute to the increased cytosolic Ca2+ concentration often observed in cells undergoing apoptosis. Finally, GFP–IP3R1-casp or GFP–IP3R1-ES can be used as a novel tool to deplete intracellular Ca2+ stores.

scholarly journals Mutational Analysis of the Ligand Binding Site of the Inositol 1,4,5-Trisphosphate Receptor

1996 ◽  
Vol 271 (30) ◽  
pp. 18277-18284 ◽  
Author(s):  
Fumio Yoshikawa ◽  
Mitsuhiro Morita ◽  
Toshiaki Monkawa ◽  
Takayuki Michikawa ◽  
Teiichi Furuichi ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Binding Site ◽  
Mutational Analysis ◽  
Ligand Binding Site ◽  
Inositol 1,4,5 Trisphosphate ◽  
Trisphosphate Receptor

The complex regulatory function of the ligand-binding domain of the inositol 1,4,5-trisphosphate receptor

Cell Calcium ◽  
2008 ◽  
Vol 43 (1) ◽  
pp. 17-27 ◽  
Author(s):  
Benoit Devogelaere ◽  
Leen Verbert ◽  
Jan B. Parys ◽  
Ludwig Missiaen ◽  
Humbert De Smedt
Keyword(s):  
Ligand Binding ◽  
Binding Domain ◽  
Ligand Binding Domain ◽  
Regulatory Function ◽  
Inositol 1,4,5 Trisphosphate ◽  
Trisphosphate Receptor

scholarly journals Crystal Structure of the Ligand Binding Suppressor Domain of Type 1 Inositol 1,4,5-Trisphosphate Receptor

2005 ◽  
Vol 17 (2) ◽  
pp. 193-203 ◽  
Author(s):  
Ivan Bosanac ◽  
Haruka Yamazaki ◽  
Toru Matsu-ura ◽  
Takayuki Michikawa ◽  
Katsuhiko Mikoshiba ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ligand Binding ◽  
Inositol 1,4,5 Trisphosphate ◽  
Trisphosphate Receptor
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