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Module 3: Figure cyclic AMP modulation of the InsP3R

Cyclic AMP modulation of the InsP3R.

The InsP3R binds a number of regulatory components that regulate its modulation by cyclic AMP-induced phosphorylation. A. Resting state. B. Cyclic AMP activates protein kinase A (PKA) to phosphorylate both DARPP-32, which enables it to inhibit the protein phosphatase 1 (PP1) thus preventing desensitization, and the InsP3R, which greatly sensitizes the latter. C. In response to InsP3 there is a large Ca2+ release. Some of this Ca2+ feeds back to stimulate calcineurin (CaN) that then dephosphorylates DARPP-32 thus removing its inhibition of PP1. D. The PP1 dephosphorylates the InsP3R resulting in a much reduced Ca2+ release. This Figure was redrawn from a figure in Chan et al. (2014).