Department of Biomedical Sciences, University of Padova, Via U. Bassi 58/B, Padova, Italy.
Proteomics Center, University of Padova and Azienda Ospedaliera di Padova, via G. Orus 2/B, Padova, Italy.
Sci Rep. 2017 Feb 17;7:42409. doi: 10.1038/srep42409.
CK2 is a ubiquitous, constitutively active, highly pleiotropic, acidophilic Ser/Thr protein kinase whose holoenzyme is composed of two catalytic (α and/or α') subunits and a dimer of a non-catalytic β subunit. Abnormally high CK2 level/activity is often associated with malignancy and a variety of cancer cells have been shown to rely on it to escape apoptosis. To gain information about the actual "druggability" of CK2 and to dissect CK2 dependent cellular processes that are instrumental to the establishment and progression of neoplasia we have exploited the CRISPR/Cas9 genome editing technology to generate viable clones of C2C12 myoblasts devoid of either both the CK2 catalytic subunits or its regulatory β-subunit. Suppression of both CK2 catalytic subunits promotes the disappearance of the β-subunit as well, through its accelerated proteasomal degradation. A quantitative proteomics analysis of CK2α/α' versus wild type cells shows that knocking out both CK2 catalytic subunits causes a rearrangement of the proteomics profile, with substantially altered level ( > 50%) of 240 proteins, 126 of which are up-regulated, while the other are down-regulated. A functional analysis reveals that up- and down-regulated proteins tend to be segregated into distinct sub-cellular compartments and play different biological roles, consistent with a global rewiring underwent by the cell to cope with the lack of CK2.
CK2 是一种普遍存在的、组成型激活的、高度多功能的、嗜酸的丝氨酸/苏氨酸蛋白激酶，其全酶由两个催化（α 和/或 α'）亚基和一个非催化β亚基的二聚体组成。异常高的 CK2 水平/活性通常与恶性肿瘤有关，多种癌细胞已被证明依赖它来逃避细胞凋亡。为了获得有关 CK2 实际“可成药性”的信息，并剖析对肿瘤发生和发展至关重要的 CK2 依赖性细胞过程，我们利用 CRISPR/Cas9 基因组编辑技术生成了缺乏 CK2 催化亚基或其调节β亚基的 C2C12 成肌细胞的存活克隆。通过其加速的蛋白酶体降解，抑制两个 CK2 催化亚基也会促进β亚基的消失。对 CK2α/α'与野生型细胞的定量蛋白质组学分析表明，敲除两个 CK2 催化亚基会导致蛋白质组学图谱发生重排，240 种蛋白质的水平发生实质性改变（>50%），其中 126 种上调，而其他下调。功能分析表明，上调和下调的蛋白质往往被分隔到不同的亚细胞区室中，并发挥不同的生物学作用，这与细胞为应对 CK2 缺乏而进行的全局重新布线一致。
