Laboratory of Molecular Cell Biology, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba, 260-8675, Japan.
Laboratory of Transcriptional Regulation in Leukemogenesis, International Research Center for Medical Sciences (IRCMS), Kumamoto University, Kumamoto, 860-0811, Japan.
Sci Rep. 2021 Jan 28;11(1):2616. doi: 10.1038/s41598-021-82189-1.
Src-family tyrosine kinases (SFKs) play important roles in a number of signal transduction events during mitosis, such as spindle formation. A relationship has been reported between SFKs and the mitotic spindle; however, the underlying mechanisms remain unclear. We herein demonstrated that SFKs accumulated in the centrosome region at the onset of mitosis. Centrosomal Fyn increased in the G phase in a microtubule polymerization-dependent manner. A mass spectrometry analysis using mitotic spindle preparations was performed to identify tyrosine-phosphorylated substrates. Protein regulator of cytokinesis 1 (PRC1) and kinastrin/small kinetochore-associated protein (kinastrin/SKAP) were identified as SFK substrates. SFKs mainly phosphorylated PRC1 at Tyr-464 and kinastrin at Tyr-87. Although wild-type PRC1 is associated with microtubules, phosphomimetic PRC1 impaired the ability to bind microtubules. Phosphomimetic kinastrin at Tyr-87 also impaired binding with microtubules. Collectively, these results suggest that tyrosine phosphorylation of PRC1 and kinastrin plays a role in their delocalization from microtubules during mitosis.
Src 家族酪氨酸激酶（SFKs）在有丝分裂过程中的许多信号转导事件中发挥重要作用，例如纺锤体的形成。已经报道了 SFKs 与有丝分裂纺锤体之间的关系；然而，潜在的机制仍不清楚。我们在此证明，SFKs 在有丝分裂开始时积累在中心体区域。中心体 Fyn 在 G 期以微管聚合依赖性方式增加。使用有丝分裂纺锤体制剂进行了质谱分析，以鉴定酪氨酸磷酸化的底物。蛋白细胞分裂调控因子 1（PRC1）和 kinastrin/小着丝粒相关蛋白（kinastrin/SKAP）被鉴定为 SFK 底物。SFKs 主要在 Tyr-464 处磷酸化 PRC1，在 Tyr-87 处磷酸化 kinastrin。尽管野生型 PRC1 与微管相关，但磷酸化模拟 PRC1 损害了与微管结合的能力。磷酸化模拟的 Tyr-87kinastrin 也损害了与微管的结合。总之，这些结果表明 PRC1 和 kinastrin 的酪氨酸磷酸化在它们有丝分裂期间从微管上的重新定位中发挥作用。
