机构：[1]Center for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Hunan, China[2]Center for Regenerative Medicine, The First People’s Hospital of Yunnan Province, Kunming, China云南省第一人民医院再生医学研究中心科研科科技教育处行政职能机构[3]School of Life Sciences, Central South University, Hunan, China[4]Hunan Key Laboratory of Basic and Applied Hematology, Central South University, Hunan, China[5]Hunan Key Laboratory of Animal Models for Human Diseases, Central South University, Hunan, China[6]Department of Cell Biology, School of Life Sciences, Central South University, Hunan, China
Aims The ubiquilin-like protein ubiquilin 2 (UBQLN2) is associated with amyotrophic lateral sclerosis and frontotemporal degeneration (ALS/FTD). The biological function of UBQLN2 has previously been shown to be related to stress granules (SGs). In this study, we aimed to clarify the regulatory relationship between UBQLN2 and SGs. Methods In this study, we transfected UBQLN2-WT or UBQLN2-P497H plasmids into cell lines (HEK293T, HeLa), and observed the process of SG dynamics by immunofluorescence. Meanwhile, immunoblot analyses the protein changes of stress granules related components. Results We observed that ubiquilin 2 colocalizes with the SG component proteins G3BP1, TIA-1, ATXN2, and PABPC1. In cells expressing WT UBQLN2 or P497H mutants, in the early stages of SG formation under oxidative stress, the percentage of cells with SGs and the number of SGs per cell decreased to varying degrees. Between WT and mutant, there was no significant difference in eIF2 alpha activity after stress treatment. Interestingly, the UBQLN2 P497H mutant downregulates the level of TIA-1. In addition, the overexpression of the UBQLN2 P497H mutant inhibited the phosphorylation of 4E-BP1 and affected the nucleoplasmic distribution of TDP-43. Conclusions Ubiquilin 2 colocalizes with the SG component proteins G3BP1, TIA-1, ATXN2, and PABPC1. It participates in regulating SG dynamics. And UBQLN2 mutation affects the assembly of stress granules by regulating TIA-1. In addition, the overexpression of the UBQLN2 P497H mutant inhibited the phosphorylation of 4E-BP1 and affected the nuclear and cytoplasmic distribution of TDP-43. These provide new insights into the role of UBQLN2 in oxidative stress and the pathogenesis of ALS.
基金：
National Key Research and Development Program
of China (2016YFC0905100), the National
Natural Science Foundation of China
(81770200), and Education and Teaching
Reform Research Project of Central South
University (2020jy144)
第一作者机构：[1]Center for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Hunan, China
共同第一作者：
通讯作者：
通讯机构：[1]Center for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Hunan, China[4]Hunan Key Laboratory of Basic and Applied Hematology, Central South University, Hunan, China[5]Hunan Key Laboratory of Animal Models for Human Diseases, Central South University, Hunan, China[6]Department of Cell Biology, School of Life Sciences, Central South University, Hunan, China[*1]Center for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, 410000 Changsha, Hunan, China[*2]Hunan Key Laboratory of Basic and Applied Hematology, Central South University, 410000 Changsha, Hunan, China
医学