Ophthalmology Research Laboratories, Department of Surgery and Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA.
J Cell Biochem. 2012 Sep;113(9):2948-56. doi: 10.1002/jcb.24171.
Protein kinase CK2 participates in a wide range of cellular events, including the regulation of cellular morphology and migration, and may be an important mediator of angiogenesis. We previously showed that in the retina, CK2 immunolocalizes mostly to vascular endothelium and astrocytes in association with the cytoskeleton. Additionally, CK2 inhibitors significantly reduced retinal neovascularization and stem cell recruitment in the mouse model of oxygen-induced proliferative retinopathy. We have also shown that CK2 and F-actin co-localized in actin stress fibers in microvascular endothelial cells, and that highly specific CK2 inhibitors caused cell rounding in astrocytes and microvascular endothelial cells, which was alleviated by serum that promotes spreading by Rho/Rho-kinase (RhoK) activation of myosin II. Therefore, we examined a possible role of CK2 in the regulation of actin-myosin II-based contractility. Treatment with CK2 inhibitors correlated with disassembly of actomyosin stress fibers and cell shape changes, including cytoplasmic retraction and process formation that were similar to those occurring during astrocyte stellation. Low doses of specific inhibitors of kinases (RhoK and MLCK) that phosphorylate myosin light chain (MLC) enhanced the effect of suboptimal CK2 inhibition on cell shape. Such striking stellation-like alteration was accompanied by decreased level of phospho-MLC, thus implying a CK2 role in regulation of actomyosin cytoskeleton. Our results suggest an important role of CK2 in the control of cell contractility and motility, which may account for suppressing effect of CK2 inhibition on retinal neovascularization. Together, our data implicate protein kinase CK2 for the first time in stellation-like morphological transformation.
蛋白激酶 CK2 参与广泛的细胞事件，包括细胞形态和迁移的调节，并且可能是血管生成的重要介质。我们之前的研究表明，在视网膜中，CK2 免疫定位主要与细胞骨架相关联，位于血管内皮细胞和星形胶质细胞上。此外，CK2 抑制剂可显著减少氧诱导的增生性视网膜病变小鼠模型中的视网膜新生血管形成和干细胞募集。我们还表明，CK2 和 F-肌动蛋白在微血管内皮细胞中的肌动蛋白应力纤维中共同定位于 F-肌动蛋白，并且高度特异性 CK2 抑制剂导致星形胶质细胞和微血管内皮细胞的细胞圆化，这可通过促进 Rho/Rho 激酶（RhoK）激活肌球蛋白 II 来促进细胞扩展的血清来缓解。因此，我们研究了 CK2 在调节基于肌动球蛋白 II 的收缩性中的可能作用。CK2 抑制剂的处理与肌动蛋白应力纤维的解聚和细胞形状变化相关，包括细胞质回缩和突起形成，这类似于星形胶质细胞星状化过程中发生的变化。低剂量的特定激酶（RhoK 和 MLCK）抑制剂可磷酸化肌球蛋白轻链（MLC），增强了亚最佳 CK2 抑制对细胞形状的影响。这种引人注目的星状样改变伴随着磷酸化 MLC 水平的降低，因此暗示 CK2 在调节肌动球蛋白细胞骨架中起作用。我们的结果表明 CK2 在控制细胞收缩性和运动性方面具有重要作用，这可能解释了 CK2 抑制对视网膜新生血管形成的抑制作用。总之，我们的数据首次表明蛋白激酶 CK2 参与了星状样形态转化。
