Laboratory of Protein Structure and Function, Institute of Medicine and Pharmacy, Qiqihar Medical University, Qiqihar, 161006, Heilongjiang, China.
Department of Histology and Embryology, Basic Medical School, Qiqihar Medical University, Qiqihar, 161006, Heilongjiang, China.
Sci Rep. 2022 Jun 11;12(1):9700. doi: 10.1038/s41598-022-13934-3.
Vacuolar protein sorting 35 (VPS35) is a major component of the retromer complex that regulates endosomal trafficking in eukaryotic cells. Recent studies have shown that VPS35 promotes tumor cell proliferation and affects the nuclear accumulation of its interacting partner. In this study, isobaric tags for relative and absolute quantitation (iTRAQ)-based mass spectrometry were used to measure the changes in nuclear protein abundance in VPS35-depleted HeLa cells. A total of 47 differentially expressed proteins were identified, including 27 downregulated and 20 upregulated proteins. Gene ontology (GO) analysis showed that the downregulated proteins included several minichromosome maintenance (MCM) proteins described as cell proliferation markers, and these proteins were present in the MCM2-7 complex, which is essential for DNA replication. Moreover, we validated that loss of VPS35 reduced the mRNA and protein expression of MCM2-7 genes. Notably, re-expression of VPS35 in VPS35 knockout HeLa cells rescued the expression of these genes. Functionally, we showed that VPS35 contributes to cell proliferation and maintenance of genomic stability of HeLa cells. Therefore, these findings reveal that VPS35 is involved in the regulation of MCM2-7 gene expression and establish a link between VPS35 and cell proliferation.
液泡蛋白分选 35（VPS35）是调节真核细胞内体运输的逆行体复合物的主要组成部分。最近的研究表明，VPS35 促进肿瘤细胞增殖，并影响其相互作用伙伴的核积累。在这项研究中，我们使用基于相对和绝对定量同位素标记（iTRAQ）的质谱法来测量 VPS35 耗尽的 HeLa 细胞中核蛋白丰度的变化。共鉴定出 47 种差异表达的蛋白质，包括 27 种下调和 20 种上调的蛋白质。基因本体（GO）分析表明，下调的蛋白质包括几个被描述为细胞增殖标志物的微小染色体维持（MCM）蛋白，这些蛋白质存在于 MCM2-7 复合物中，该复合物对于 DNA 复制至关重要。此外，我们验证了 VPS35 的缺失降低了 MCM2-7 基因的 mRNA 和蛋白质表达。值得注意的是，在 VPS35 敲除的 HeLa 细胞中重新表达 VPS35 挽救了这些基因的表达。功能上，我们表明 VPS35 有助于 HeLa 细胞的增殖和基因组稳定性的维持。因此，这些发现表明 VPS35 参与了 MCM2-7 基因表达的调节，并在 VPS35 和细胞增殖之间建立了联系。
