CLONING OF AN INTRACELLULAR RECEPTOR FOR PROTEIN-KINASE-C - A HOMOLOG OF THE BETA-SUBUNIT OF G-PROTEINS
CLONING OF AN INTRACELLULAR RECEPTOR FOR PROTEIN-KINASE-C - A HOMOLOG OF THE BETA-SUBUNIT OF G-PROTEINS
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DOI：
10.1073/pnas.91.3.839
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发表时间：
1994-02-01
影响因子：
11.1
通讯作者：
MOCHLYROSEN, D
中科院分区：
文献类型：
--
作者：
RON, D;CHEN, CH;MOCHLYROSEN, D
蛋白激酶C（PKC）在活化时从可溶性部分易位到细胞颗粒部分。结合颗粒部分中活化的PKC的细胞内受体已被许多研究所牵连。以前的工作确定了30- 36-kDa的蛋白质在心脏和大脑的颗粒部分，结合激活的PKC在一个特定的和饱和的方式。这些蛋白质被称为活化C-激酶受体，或RACK。在下面的研究中，我们描述了一个cDNA编码的36 kDa的蛋白质（RACK 1），满足RACKs的标准的克隆。(i)RACK 1结合PKC激活剂的存在下，但不是在他们的缺席。(ii)PKC与重组RACK 1的结合不受假底物肽或来自假底物序列的底物肽的抑制，这表明结合并不简单地反映PKC与其底物的结合。(iii)PKC与RACK 1的结合是饱和的和特异性的;另外两种蛋白激酶不与RACK 1结合。(iv)RACK 1含有两个短序列同源的PKC结合序列以前确定在膜联蛋白I和脑PKC抑制剂KCIP。从这些序列衍生的肽抑制PKC与RACK 1的结合。最后，RACK 1是G蛋白的β亚基的同源物，其最近与β-肾上腺素能受体激酶的膜锚定有关[Pitcher，J.，英格莱斯湖Higgins，J. B.，阿里扎，JA，凯西，PJ，金角，澳-地Benovic，J.L.，Kwatra，M. M.，卡伦，M. G. & Lefkowitz，R. J.（1992）Science 257，1264-12671中所述。我们的体外数据表明RACK 1在PKC介导的信号传导中的作用。
Protein kinase C (PKC) translocates from the soluble to the cell particulate fraction on activation. Intracellular receptors that bind activated PKC in the particulate fraction have been implicated by a number of studies. Previous work identified 30- to 36-kDa proteins in the particulate fraction of heart and brain that bound activated PKC in a specific and saturable manner. These proteins were termed receptors for activated C-kinase, or RACKs. In the following study, we describe the cloning of a cDNA encoding a 36-kDa protein (RACK1) that fulfills the criteria for RACKs. (i) RACK1 bound PKC in the presence of PKC activators, but not in their absence. (ii) PKC binding to the recombinant RACK1 was not inhibited by a pseudosubstrate peptide or by a substrate peptide derived from the pseudosubstrate sequence, indicating that the binding did not reflect simply PKC association with its substrate. (iii) Binding of PKC to RACK1 was saturable and specific; two other protein kinases did not bind to RACK1. (iv) RACK1 contains two short sequences homologous to a PKC binding sequence previously identified in annexin I and in the brain PKC inhibitor KCIP. Peptides derived from these sequences inhibited PKC binding to RACK1. Finally, RACK1 is a homolog of the beta subunit of G proteins, which were recently implicated in membrane anchorage of the beta-adrenergic receptor kinase [Pitcher, J., Inglese, L., Higgins, J. B., Arriza, J. A., Casey, P. J., Kim, C., Benovic, J. L., Kwatra, M. M., Caron, M. G. & Lefkowitz, R. J. (1992) Science 257, 1264-12671. Our in vitro data suggest a role for RACK1 in PKC-mediated signaling.