ABSTRACT: The total protein of bone marrw myeloma cells was extracted with cell lysis buffer for IP. YBX1 antibody was used to perform Immunoprecipitation.
Project description:URI keeps low levels of p53 in a TRIM28-MDM2 dependent manner, maintains SCD1 activity and accumulation of MUFAs, and subsequently promotes resistance to TKIs in cancer cell. URI-p53-SCD1 axis mediates resistance of TKIs and may explain why p53-wild type HCC still showed intrinsic resistance to TKIs. Moreover, the combination therapy identified here may represent a promising strategy for the approximately 41% of patients with advanced HCC who have wild-type p53 and high levels of URI/SCD1.
Project description:Obesity is a metabolic disease accompanied by lipid metabolism that can cause hyperlipidemia, non-alcoholic fatty liver disease, and artery atherosclerosis. Sleeve gastrectomy (SG) is a type of bariatric surgery that can effectively treat obesity and improve lipid metabolism. However, its specific underlying mechanism remains unclear. Therefore, we herein performed SG, and sham surgery on two groups of diet-induced obese mice. The results showed that compared to the sham group, the SG group displayed a downregulation of deubiquitinase ubiquitin-specific peptidase 20 (USP20). And USP20 could promote lipid accumulation in vitro. Co-immunoprecipitation and mass spectrometry analyses showed that heat-shock protein family A member 2 (HSPA2) potentially acts as a substrate of USP20. HSPA2 was also downregulated in the SG group and could promote lipid accumulation in vitro. Further research showed that USP20 targeted and stabilized HSPA2 via the ubiquitin-proteasome pathway. The downregulation of the USP20-HSPA2 axis in diet-induced obese mice following SG improved lipid dysmetabolism, indicating that USP20-HSPA2 axis was a noninvasive therapeutic treatment to be investigated in the future.
Project description:In order to identify YBX1 binding sites on endogenous RNA, we performed HITS-CLIP on endogenous YBX1 We used a previously published method to perform HITS-CLIP on endogenous YBX1 (Licatalosi D, et al. 2008, Nature 456:464-U22)
Project description:Lysine acetylation and ubiquitination are one of many protein modifications and play a crucial role in the biological regulation of many organisms, but little is known about the relationship between acetylation and ubiquitination few. Here, the Isw1 protein is an important member of the chromatin remodeling complex, and we performed single-protein modification mass spectrometry detection of the C. neoformans Isw1 protein and site mutations for both detected modifications. The data showed that the two modifications of Cryptococcus neoformans Isw1 protein have a balance of each other. Acetylation can maintain protein stability and maintain protein function, while ubiquitination can reduce protein level and maintain Isw1 protein expression. The expression level of Isw1 protein leads to resistance to antifungal drugs. These results reveal the resistance mechanism of Isw1 protein of Cryptococcus neoformans to antifungal drugs.
Project description:Pili on the surface of Sulfolobus islandicus are used for a host of functions, and serve as receptors for certain archaeal viruses. We find that these pili, when removed from cells, resist digestion by trypsin or pepsin, and survive boiling in SDS or 5M guanidinium-HCl. We have used cryo-EM to determine the structure of these filaments at 4.1 Å resolution. An atomic model was built by combining the map with bioinformatics without prior knowledge of the pilin sequence, an approach that should prove useful when looking at assemblies where all of the components may not be known. The atomic structure of the archaeal pilus was unusual due to almost a third of the residues being either threonine or serine and many hydrophobic surface residues. While the map showed specific glycosylation of only three residues, mass per unit length measurements suggested extensive glycosylation. We show that this extensive glycosylation renders these filaments soluble and provides the remarkable structural stability. We also show that the overall fold of the archaeal pilin is quite similar to archaeal flagellin, establishing common evolutionary origins.
Project description:In order to identify YBX1 binding sites on tRNA fragments, we performed small-RNA HITS-CLIP on endogenous YBX1 We used a previously published method to perform HITS-CLIP on endogenous YBX1 (Chi SW, et al. 2009, Nature 460:479)
Project description:YBX1 is a multifunctional protein involved in the control of transcription and translation. We identified YBX1 as an target of MEK/ERK signaling in colorectal cancer cell lines. We performed a ChIP-chip analysis of HCT116 cells to identify new potential target genes of YBX1. Comparison of input DNA fragments with fragments coprecipitated with YBX1 in HCT116 cells.
Project description:In order to identify YBX1-dependent targets that are modulated under hypoxic conditions, we used control and YBX1 knockdown cells grown under normoxia and hypoxia to profile gene expression levels. Control and YBX1-knockdown cells were grown and profiled under hypoxia and normoxia to identify YBX1-dependent hypoxia-induced target transcripts.
Project description:The control of p53 protein stability is critical to its tumor suppressor functions. The CREB Binding Protein (CBP) transcriptional coactivator co-operates with MDM2 to maintain normally low physiologic p53 levels in cells via an exclusively cytoplasmic ‘E4’ polyubiquitination activity. Utilizing mass spectrometry to identify nuclear and cytoplasmic CBP interacting proteins that regulate compartmentalized CBP E4 activity, we identified Deleted in Breast Cancer 1 (DBC1) as a stoichiometric CBP-interacting protein that negatively regulates CBP–dependent p53 polyubiquitination, stabilizes p53, and augments p53-dependent apoptosis. TCGA analysis demonstrated that solid tumors often retain wild type p53 alleles in conjunction with DBC1 loss, supporting the hypothesis that DBC1 is selected for disruption during carcinogenesis as a surrogate for p53 functional loss. As DBC1 maintains p53 stability in the nucleus where p53 exerts its tumor suppressive transcriptional function, replacement of DBC1 functionality in DBC1-deleted tumors might also enhance p53 function and chemosensitivity for therapeutic benefit.
Project description:In order to identify YBX1-dependent targets that are modulated upon changing the levels of endogenous tRFs, we used transient transfection of antisense locked-nucleic acids (LNAs) against tRFAsp, tRFGly, tRFGlu, and tRFTyr followed by microarray profiling. Synthetic antisense locked-nucleic acids (LNAs) targeting the YBX1 binding site on tRFAsp, tRFGly, tRFGlu, and tRFTyr were transfected into control and YBX1-knockdown cells to identify YBX1-dependent targets that are modulated due to tRF loss-of-function.