Binding specificity for RACK1 resides in the V5 region of βII protein kinase C
Binding specificity for RACK1 resides in the V5 region of βII protein kinase C
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DOI：
10.1074/jbc.m101044200
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发表时间：
2001-08-10
影响因子：
4.8
通讯作者：
Mochly-Rosen, D
中科院分区：
文献类型：
--
作者：
Stebbins, EG;Mochly-Rosen, D
对负责特定信号蛋白特异性定位的选择性锚定蛋白的鉴定，导致了新的信号转导抑制剂以及锚定蛋白 - 配体相互作用抑制剂的发现。RACK1是我们实验室发现的第一个活化C激酶受体，它是βII蛋白激酶C（βIIPKC）的一种选择性锚定蛋白。我们先前发现，至少部分RACK1结合位点位于βIIPKC的C2结构域（Ron, D., Luo, J., 和Mochly - Rosen, D. (1995) J. Biol. Chem. 270, 24180 - 24187）。在此我们表明，V5结构域也包含βIIPKC中部分RACK1结合位点。在新生大鼠心肌细胞中，βIIPKC肽（βIIPKC中的氨基酸645 - 650）选择性地抑制佛波醇12 - 肉豆蔻酸13 - 乙酸酯（PMA）诱导的βIIPKC的转位，而不抑制βIPKC的转位。此外，βIIV5 - 3肽抑制了PMA处理细胞中的心肌细胞肥大。有趣的是，βIV5 - 3（βIPKC中的646 - 651），一种βIPKC的选择性转位抑制剂，也抑制了PMA诱导的心肌细胞肥大，这表明βI - 和βIIPKC对这种心脏功能都是必不可少的。因此，βIIV5结构域包含βIIPKC中部分RACK1结合位点；对应于此位点的肽是βIIPKC的选择性抑制剂，因此能够鉴定βIIPKC的选择性功能。
Identification of selective anchoring proteins responsible for specialized localization of specific signaling proteins has led to the identification of new inhibitors of signal transduction, inhibitors of anchoring protein-ligand interactions. RACK1, the first receptor for activated C kinase identified in our lab, is a selective anchoring protein for beta II protein kinase C (beta IIPKC). We previously found that at least part of the RACK1-binding site resides in the C2 domain of beta IIPKC (Ron, D., Luo, J., and Mochly-Rosen, D. (1995) J. Biol. Chem. 270, 24180-24187). Here we show that the V5 domain also contains part of the RACK1-binding site in beta IIPKC. In neonatal rat cardiac myocytes, the beta IIPKC peptide (amino acids 645-650 in beta IIPKC) selectively inhibited phorbol 12-myristate 13-acetate (PMA)-induced translocation of beta IIPKC and not beta IIPKC. In addition, the beta IIV5-3 peptide inhibited cardiac myocyte hypertrophy in PMA-treated cells. Interestingly, beta IV5-3 (646-651 in beta IPKC), a selective translocation inhibitor of beta IPKC, also inhibited PMA-induced cardiac myocyte hypertrophy, demonstrating that both betaI- and beta IIPKC are essential for this cardiac function. Therefore, the beta IIV5 domain contains part of the RACK1-binding site in beta IIPKC; a peptide corresponding to this site is a selective inhibitor of beta IIPKC and, hence, enables the identification of beta IIPKC-selective functions.