G蛋白偶联受体激酶5在有丝分裂中的作用

G蛋白偶联受体激酶（GRK）是G蛋白偶联受体（GPCR）信号通路的负性调节因子。近来的研究发现,GRK除了磷酸化G蛋白偶联受体使其脱敏外,还能与其他非受体底物结合,功能呈现多样性。GRK5是GRK家族成员之一,该研究探索了GRK5在细胞周期和有丝分裂中的作用,结果显示：在细胞内干扰GRK5的表达导致分裂中期的细胞数目增多和细胞凋亡。进一步的研究发现,干扰GRK5的表达导致有丝分裂中期的染色体不能正常排列到赤道板,而对分裂后期染色质分离以及胞质分裂没有影响。在细胞内干扰GRK蛋白家族的另一个成员GRK2对有丝分裂则没有明显影响。该研究提示GRK5是细胞有丝分裂的重要调控蛋白。

The Role of GRK5 in Mitosis

G protein-coupled receptor（GPCR） kinases（GRKs） are known as a family of serine/threonine kinases that desensitize GPCR signaling by phosphorylating agonist-occupied receptors.Receptor phosphorylation catalyzed by GRK leads to the recruitment of arrestins to the cell membrane and the internalization of GPCRs.GRKs are also capable to phosphorylate a variety of non-GPCR substrates and regulate several signaling pathways via direct interactions with other proteins in a phosphorylation-independent manner.GRK5 is an important member of GRKs.The current study explored potential roles of GRK5 in cell cycle and cell mitosis.Our results showed that knockdown of GRK5 arrests cells in metaphase and induces cell apoptosis.Using DAPI labeling chromosome,we found that knockdown of GRK5 induces chromosome misalignment but has no effect on cytokinesis.However,knockdown of GRK2,another member of GRKs,has no effect on cell cycle and cell mitosis.Our results suggest that GRK5 is an important regulator of cell mitosis.