ABSTRACT
A large amount of data and observations on inositol 1,4,5-trisphosphate (IP^sub 3^) binding to the IP^sub 3^ receptor/Ca^sup 2+^ channel, the steady-state activity of the channel, and its inactivation by IP^sub 3^ can be explained by assuming one activation and one inhibition module, both allosterically operated by Ca^sup 2+^, IP^sub 3^, and ATP, and one adaptation element, driven by IP^sub 3^, Ca^sup 2+^, and the interconversion between two possible conformations of the receptor. The adaptation module becomes completely insensitive to a second IP^sub 3^ pulse within 80 s. Observed kinetic responses are well reproduced if, in addition, two module open states are rendered …
No comments:
Post a Comment