Piggott Leslie A, Bauman Andrea L, Scott John D, Dessauer Carmen W
Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA.
Proc Natl Acad Sci U S A. 2008 Sep 16;105(37):13835-40. doi: 10.1073/pnas.0712100105. Epub 2008 Sep 4.
A-kinase anchoring proteins (AKAPs) influence the spatial and temporal regulation of cAMP signaling events. Anchoring of PKA in proximity to certain adenylyl cyclase (AC) isoforms is thought to enhance the phosphorylation dependent termination of cAMP synthesis. Using a combination of immunoprecipitation and enzymological approaches, we show that the plasma membrane targeted anchoring protein AKAP9/Yotiao displays unique specificity for interaction and the regulation of a variety of AC isoforms. Yotiao inhibits AC 2 and 3, but has no effect on AC 1 or 9, serving purely as a scaffold for these latter isoforms. Thus, Yotiao represents an inhibitor of AC2. The N terminus of AC2 (AC2-NT), which binds directly to amino acids 808-957 of Yotiao, mediates this interaction. Additionally, AC2-NT and Yotiao (808-957) are able to effectively inhibit the association of AC2 with Yotiao and, thus, reverse the inhibition of AC2 by Yotiao in membranes. Finally, disruption of Yotiao-AC interactions gives rise to a 40% increase in brain AC activity, indicating that this anchoring protein functions to directly regulate cAMP production in the brain.
A激酶锚定蛋白（AKAPs）影响cAMP信号事件的时空调节。蛋白激酶A（PKA）与某些腺苷酸环化酶（AC）亚型的接近锚定被认为会增强cAMP合成的磷酸化依赖性终止。通过免疫沉淀和酶学方法相结合，我们发现靶向质膜的锚定蛋白AKAP9/Yotiao对多种AC亚型的相互作用和调节具有独特的特异性。Yotiao抑制AC 2和AC 3，但对AC 1或AC 9没有影响，仅作为后两种亚型的支架。因此，Yotiao是AC2的一种抑制剂。AC2的N末端（AC2-NT）直接与Yotiao的808-957位氨基酸结合，介导了这种相互作用。此外，AC2-NT和Yotiao（808-957）能够有效抑制AC2与Yotiao的结合，从而逆转Yotiao对膜中AC2的抑制作用。最后，Yotiao与AC相互作用的破坏导致脑AC活性增加40%，表明这种锚定蛋白直接调节脑中cAMP的产生。
