Kin17是通过其对针对原核RecA的抗体的免疫反应性而发现的蛋白质。对Kin17的进一步研究揭示了DNA复制和修复的功能,以及在前mRNA处理中。最近,发现新发现的甲基转移酶METTL22使Kin17在赖氨酸135上甲基化。为了更好地理解Kin17的功能及其通过甲基化的调节,我们使用多细胞区室蛋白亲和纯化与质谱联用(MCC-AP-MS)来鉴定Kin17的新的相互作用伴侣,并评估这些相互作用是否可以在染色质上发生.我们的结果证实Kin17与METTL22在可溶性和染色质部分相互作用。我们还表明,许多RNA结合蛋白,包括先前确定的相互作用子BUD13以及剪接体和核糖体亚基,与可溶性部分中的Kin17缔合。有趣的是,METTL22在HEK293细胞中的过表达将Kin17从染色质转移到细胞质部分,提示赖氨酸135的甲基化在调节与染色质的关联中的作用,赖氨酸135是位于Kin17的有翼螺旋结构域内的残基。鉴于Kin17的推定细胞功能讨论了这些结果。
■此处显示的结果扩大了我们对METTL22的理解,METTL22是新发现的非组蛋白赖氨酸甲基转移酶及其底物家族的成员,Kin17,一种DNA/RNA结合蛋白,据报道在DNA修复和复制以及mRNA加工中起作用。一种研究多个细胞区室中蛋白质-蛋白质相互作用的创新方法用于概述两种蛋白质的相互作用网络。功能实验揭示了Kin17赖氨酸甲基化及其与染色质关联之间的相关作用。本文是特刊的一部分,题为:蛋白质组学可以填补基因组学和表型之间的差距吗?
Kin17 is a protein that was discovered through its immunoreactivity towards an antibody directed against prokaryotic RecA. Further study of Kin17 revealed a function in DNA replication and repair, as well as in pre-mRNA processing. Recently, it was found that Kin17 is methylated on lysine 135 by the newly discovered methyltransferase METTL22. To better understand the function of Kin17 and its regulation by methylation, we used multiple cell compartment protein affinity purification coupled with mass spectrometry (MCC-AP-MS) to identify novel interaction partners of Kin17 and to assess whether these interactions can take place on chromatin. Our results confirm that Kin17 interacts with METTL22 both in the soluble and chromatin fractions. We also show that many RNA-binding proteins, including the previously identified interactor BUD13 as well as spliceosomal and ribosomal subunits, associate with Kin17 in the soluble fraction. Interestingly, overexpression of METTL22 in HEK 293 cells displaces Kin17 from the chromatin to the cytoplasmic fraction, suggesting a role for methylation of lysine 135, a residue that lies within a winged helix domain of Kin17, in regulating association with chromatin. These results are discussed in view of the putative cellular function of Kin17.
UNASSIGNED: The results shown here broaden our understanding of METTL22, a member of a family of newly-discovered non-histone lysine methyltransferases and its substrate, Kin17, a DNA/RNA-binding protein with reported roles in DNA repair and replication and mRNA processing. An innovative method to study protein-protein interactions in multiple cell compartments is employed to outline the interaction network of both proteins. Functional experiments uncover a correlative role between Kin17 lysine methylation and its association with chromatin. This article is part of a Special Issue entitled: Can Proteomics Fill the Gap Between Genomics and Phenotypes?