scholarly journals Two potential calmodulin-binding sequences in the ryanodine receptor contribute to a mobile, intra-subunit calmodulin-binding domain

2013 ◽  
Vol 126 (19) ◽  
pp. 4527-4535 ◽  
Author(s):  
X. Huang ◽  
Y. Liu ◽  
R. Wang ◽  
X. Zhong ◽  
Y. Liu ◽  
...  
Keyword(s):  
Ryanodine Receptor ◽  
Binding Domain ◽  
Calmodulin Binding

Interaction of the Lys3614–Asn3643 calmodulin-binding domain with the Cys4114-Asn4142 region of the type 1 ryanodine receptor is involved in the mechanism of Ca2+/agonist-induced channel activation

2008 ◽  
Vol 411 (2) ◽  
pp. 415-423 ◽  
Author(s):  
Jaya P. Gangopadhyay ◽  
Noriaki Ikemoto
Keyword(s):  
Ryanodine Receptor ◽  
Binding Activity ◽  
Significant Inhibition ◽  
Binding Domain ◽  
Domain Pair ◽  
Dependent Manner ◽  
Domain Interaction ◽  
Channel Activation ◽  
Calmodulin Binding

In the present study we show that the interaction of the CaM (calmodulin)-binding domain (Lys3614–Asn3643) with the Cys4114–Asn4142 region (a region included in the CaM-like domain) serves as an intrinsic regulator of the RyR1 (type-1 ryanodine receptor). We tested the effects of antibodies raised against the two putative key regions of RyR1 [anti-(Lys3614–Asn3643) and anti-(Cys4114–Asn4142) antibodies]. Both antibodies produced significant inhibition of [3H]ryanodine-binding activity of RyR1. This suggests that the inter-domain interaction between the two domains, Lys3614–Asn3643 and Cys4114–Asn4142, activates the channel, and that the binding of antibody to either side of the interacting domain pair interfered with the formation of a ‘channel-activation link’ between the two regions. In order to spectroscopically monitor the mode of interaction of these domains, the site of inter-domain interaction was fluorescently labelled with MCA [(7-methoxycoumarin-4-yl)acetyl] in a site-directed manner. The accessibility of the bound MCA to a large molecular mass fluorescence quencher, BSA-QSY (namely, the size of a gap between the interacting domains) decreased with an increase of [Ca2+] in a range of 0.03–2.0 μM, as determined by Stern–Volmer fluorescence quenching analysis. The Ca2+-dependent decrease in the quencher accessibility was more pronounced in the presence of 150 μM 4-CmC (4-chlorometacresol), and was reversed by 1 mM Mg2+ (a well-known inhibitor of Ca2+/agonist-induced channel activation). These results suggest that the Lys3614–Asn3643 and Cys4114–Asn4142 regions of RyR1 interact with each other in a Ca2+- and agonist-dependent manner, and this serves as a mechanism of Ca2+- and agonist-dependent activation of the RyR1 Ca2+ channel.

scholarly journals Modulation of erythrocyte Ca2+-ATPase by selective calpain cleavage of the calmodulin-binding domain

1989 ◽  
Vol 264 (14) ◽  
pp. 8289-8296 ◽  
Author(s):  
P James ◽  
T Vorherr ◽  
J Krebs ◽  
A Morelli ◽  
G Castello ◽  
...  
Keyword(s):  
Binding Domain ◽  
Calmodulin Binding

scholarly journals The Calmodulin Binding Domain of the Plasma Membrane Ca2+ Pump Interacts Both with Calmodulin and with Another Part of the Pump

1989 ◽  
Vol 264 (21) ◽  
pp. 12313-12321 ◽  
Author(s):  
A Enyedi ◽  
T Vorherr ◽  
P James ◽  
D J McCormick ◽  
A G Filoteo ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Binding Domain ◽  
Calmodulin Binding
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