CAMP SIGNALING IN NEURONS - PATTERNS OF NEURONAL EXPRESSION AND INTRACELLULAR-LOCALIZATION FOR A NOVEL PROTEIN, AKAP-150, THAT ANCHORS THE REGULATORY SUBUNIT OF CAMP-DEPENDENT PROTEIN KINASE-II-BETA
CAMP SIGNALING IN NEURONS - PATTERNS OF NEURONAL EXPRESSION AND INTRACELLULAR-LOCALIZATION FOR A NOVEL PROTEIN, AKAP-150, THAT ANCHORS THE REGULATORY SUBUNIT OF CAMP-DEPENDENT PROTEIN KINASE-II-BETA
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DOI：
10.1091/mbc.3.11.1215
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发表时间：
1992-11-01
影响因子：
3.3
通讯作者：
RUBIN, CS
中科院分区：
文献类型：
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作者：
GLANTZ, SB;AMAT, JA;RUBIN, CS
在哺乳动物的脑中，环磷酸腺苷(CAMP)携带的生理信号似乎通过cAMP依赖的蛋白激酶IIbeta(PKAIIbeta)与细胞内结构的连接而定位于效应部位。最近鉴定的A激酶锚定蛋白(AKAP)可能是PKAIIbeta隔离的介体，因为它们包含一个高亲和力的结合位点和一个独特的细胞内靶向结构域。为了建立这种靶向机制的细胞基础，我们使用免疫细胞化学方法1)鉴定富含AKAP的神经元类型，2)确定锚蛋白在细胞内的主要位置，3)证明AKAP和RIIbeta共浓缩并共存于利用腺苷环化酶-环磷酸腺苷依赖蛋白激酶(PKA)信号通路的神经元中。针对大鼠脑AKAP 150的抗体被用来阐明一个原型锚蛋白在中枢神经系统中的区域、细胞和细胞内的分布。AKAP 150在浦肯野细胞以及嗅球、基底节、大脑皮质和其他前脑区域的神经元中含量丰富。相比之下，在丘脑、下丘脑、中脑和后脑的神经元中检测到少量的AKAP 150。总AKAP150的很大比例集中在树突的初级分支，在那里它与微管有关。我们还发现，RIIbeta(和PKAIIbeta)在脑内的积累和定位模式与AKAP 150相似。结果表明，双功能AKAP 150将PKAIIbeta连接到树突状细胞骨架上，从而为cAMP携带的信号的接收和传播创造了一个离散的靶点。
In mammalian brain, physiological signals carried by cyclic AMP (cAMP) seem to be targeted to effector sites via the tethering of cAMP-dependent protein kinase IIbeta (PKAIIbeta) to intracellular structures. Recently characterized A kinase anchor proteins (AKAPs) are probable mediators of the sequestration of PKAIIbeta because they contain a high-affinity binding site for the regulatory subunit (RIIbeta) of the kinase and a distinct intracellular targeting domain. To establish a cellular basis for this targeting mechanism, we have employed immunocytochemistry to 1) identify the types of neurons that are enriched in AKAPs, 2) determine the primary intracellular location of the anchor protein, and 3) demonstrate that an AKAP and RIIbeta are coenriched and colocalized in neurons that utilize the adenylate cyclase-cyclic AMP-dependent protein kinase (PKA) signaling pathway. Antibodies directed against rat brain AKAP 150 were used to elucidate the regional, cellular and intracellular distribution of a prototypic anchor protein in the CNS. AKAP 150 is abundant in Purkinje cells and in neurons of the olfactory bulb, basal ganglia, cerebral cortex, and other forebrain regions. In contrast, little AKAP 150 is detected in neurons of the thalamus, hypothalamus, midbrain, and hindbrain. A high proportion of total AKAP 150 is concentrated in primary branches of dendrites, where it is associated with microtubules. We also discovered that the patterns of accumulation and localization of RIIbeta (and PKAIIbeta) in brain are similar to those of AKAP 150. The results suggest that bifunctional AKAP 150 tethers PKAIIbeta to the dendritic cytoskeleton, thereby creating a discrete target site for the reception and propagation of signals carried by cAMP.