A novel lipid-anchored A-kinase anchoring protein facilitates cAMP-responsive membrane events
A novel lipid-anchored A-kinase anchoring protein facilitates cAMP-responsive membrane events
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DOI：
10.1093/emboj/17.8.2261
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发表时间：
1998-04-15
期刊：
影响因子：
11.4
通讯作者：
Scott, JD
中科院分区：
文献类型：
--
作者：
Fraser, IDC;Tavalin, SJ;Scott, JD
蛋白激酶与底物的区室化是一种可能促进细胞内磷酸化事件特异性的机制。我们克隆了一种低分子量的A-激酶转运蛋白，称为AKAP 18，它将cAMP依赖性蛋白激酶（PKA）靶向质膜，并允许与L-型钙通道功能性偶联。膜锚定由AKAP 18的前10个氨基酸介导，并且涉及残基Gly 1、Cys 4和Cys 5，其分别通过豆蔻酰化和双棕榈酰化进行脂质修饰。将AKAP 18瞬时转染到表达心脏L型Ca 2+通道的HEK-293细胞中，促进cAMP响应性Ca 2+电流增加34 +/- 9%。相反，AKAP 18的靶向缺陷突变体对cAMP类似物的应用对Ca 2+电流没有影响。进一步的研究表明，AKAP 18促进胰腺β细胞系（RINm 5 F）中GLP-1介导的胰岛素分泌，表明激酶的膜锚定参与可能涉及离子通道激活的生理学相关cAMP应答事件。
Compartmentalization of protein kinases with substrates is a mechanism that may promote specificity of intracellular phosphorylation events. We have cloned a low-molecular weight A-kinase Anchoring Protein, called AKAP18, which targets the cAMP-dependent protein kinase (PKA) to the plasma membrane, and permits functional coupling to the L-type calcium channel. Membrane anchoring is mediated by the first 10 amino acids of AKAP18, and involves residues Gly1, Cys4 and Cys5 which are lipid-modified through myristoylation and dual palmitoylation, respectively. Transient transfection of AKAP18 into HEK-293 cells expressing the cardiac L-type Ca2+ channel promoted a 34 +/- 9% increase in cAMP-responsive Ca2+ currents. In contrast, a targeting-deficient mutant of AKAP18 had no effect on Ca2+ currents in response to the application of a cAMP analog. Further studies demonstrate that AKAP18 facilitates GLP-1-mediated insulin secretion in a pancreatic beta cell line (RINm5F), suggesting that membrane anchoring of the kinase participates in physiologically relevant cAMP-responsive events that may involve ion channel activation.