Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical & Health Sciences, Hiroshima University, 1-2-3 Kausmi, Minami-ku, Hiroshima, 734-8551, Japan; Department of Dental Anesthesiology, Graduate School of Biomedical & Health Sciences, Hiroshima University, 1-2-3 Kausmi, Minami-ku, Hiroshima 734-8551, Japan.
Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, 1-1 Rokkodai-cho Nada-ku, Kobe, 675-8501, Japan.
J Pharmacol Sci. 2018 May;137(1):20-29. doi: 10.1016/j.jphs.2018.03.008. Epub 2018 Apr 6.
Propofol is the most commonly used anesthetic. Immunohistochemical studies have reported that propofol translocated protein kinase Cs (PKCs) in cardiomyocyte in a subtype-specific manner; however detailed features of the propofol-induced translocation of PKCs remain unknown. In this study, we performed real-time observation of propofol-induced PKC translocation in SH-SY5Y cells expressing PKCs fused with a fluorescent protein. Propofol unidirectionally translocated γPKC-GFP, a conventional PKC, and ζPKC-GFP, an atypical PKC, to the plasma membrane and nucleus, respectively, whereas the propofol-induced translocation of novel PKCs was diverse and subtype-specific among δPKC, εPKC and ηPKC. The propofol-induced translocation of εPKC-GFP was especially complicated and diverse, that is, 200 μM propofol first translocated εPKC-GFP to the perinuclear region. Thereafter, εPKC was translocated to the nucleus, followed by translocation to the plasma membrane. Analysis using a mutant εPKC in which the C1 domain was deleted demonstrated that the C1b domain of εPKC was indispensable for its translocation to the perinuclear region and plasma membrane, but not for its nuclear translocation. An in vitro kinase assay revealed that propofol increased the activities of the PKCs activities at the concentration that triggered the translocation. These results suggest that propofol could translocate PKCs to their appropriate target sites in a subtype-specific manner and concomitantly activated PKCs at these sites, contributing to its beneficial or adverse effects.
异丙酚是最常用的麻醉剂。免疫组织化学研究报道，异丙酚以亚型特异性方式将蛋白激酶 C（PKC）易位至心肌细胞中；然而，PKC 易位的详细特征仍不清楚。在这项研究中，我们通过实时观察表达与荧光蛋白融合的 PKC 的 SH-SY5Y 细胞中异丙酚诱导的 PKC 易位来进行研究。异丙酚将 γPKC-GFP（一种常规 PKC）和 ζPKC-GFP（一种非典型 PKC）分别单向易位至质膜和核内，而新型 PKC（δPKC、εPKC 和 ηPKC）的异丙酚诱导易位则具有多样性和亚型特异性。εPKC-GFP 的异丙酚诱导易位尤其复杂和多样化，即 200μM 异丙酚首先将 εPKC-GFP 易位至核周区域。此后，εPKC 易位至核内，随后易位至质膜。使用 C1 结构域缺失的突变型 εPKC 的分析表明，εPKC 的 C1b 结构域对于其向核周区域和质膜的易位是必不可少的，但对于其向核内的易位不是必需的。体外激酶测定表明，在触发易位的浓度下，异丙酚增加了 PKC 的活性。这些结果表明，异丙酚可以以亚型特异性的方式将 PKC 易位至其适当的靶位，并同时在这些靶位上激活 PKC，从而发挥其有益或有害作用。
