Dodge-Kafka Kimberly L, Langeberg Lorene, Scott John D
Pat and Jim Calhoun Center for Cardiology, University of Connecticut Health Center, Farmington, CT 06030, USA.
Circ Res. 2006 Apr 28;98(8):993-1001. doi: 10.1161/01.RES.0000218273.91741.30.
The activation of the cyclic nucleotide protein kinase A (PKA) and PKG by their respective second messengers is responsible for the modulation of many cellular functions in the heart including cardiac hypertrophy, strength of contraction, and ion flux. However, several studies have revealed that a general increase in cyclic nucleotide concentration in the cell is not sufficient for the specific regulation of target proteins. These studies found that PKA and PKG must be colocalized with their targets to ensure spatial-temporal control of substrate phosphorylation. This compartmentation of cyclic nucleotide signaling is accomplished by tethering the protein kinases with their respective substrates through the association with scaffolding proteins. For cAMP signaling, A-kinase anchoring proteins (AKAPs) provide a molecular mechanism for cAMP compartmentation, allowing for the precise control of PKA-mediated phosphorylation events. (cAMP, PKA, AKAP, PKG).
环核苷酸蛋白激酶A（PKA）和蛋白激酶G（PKG）分别被其相应的第二信使激活，这负责调节心脏中的许多细胞功能，包括心肌肥大、收缩强度和离子通量。然而，多项研究表明，细胞中环核苷酸浓度的普遍升高不足以对靶蛋白进行特异性调节。这些研究发现，PKA和PKG必须与其靶标共定位，以确保底物磷酸化的时空控制。环核苷酸信号的这种区室化是通过与支架蛋白结合，将蛋白激酶与其各自的底物拴系来实现的。对于cAMP信号传导，A激酶锚定蛋白（AKAPs）为cAMP区室化提供了一种分子机制，从而实现对PKA介导的磷酸化事件的精确控制。（cAMP、PKA、AKAP、PKG）
