Quantitative Proteomics Analysis of the Effects of Ionizing Radiation in Wild Type and p53K317R Knock-in Mouse Thymocytes

Abstract

The tumor suppressor protein p53 is a sequence-specific transcription factor that has crucial roles in apoptosis, cell cycle arrest, cellular senescence, and DNA repair. Following exposure to a variety of stresses, p53 becomes posttranslationally modified with concomitant increases in activity and stability. To better understand the role of acetylation of Lys-317 in mouse p53, the effect of ionizing radiation (IR) on the thymocytes of p53 K317R knock-in mice was studied at the global level. Using cleavable ICAT quantitative mass spectrometry, the effect of IR on protein levels in either the wild type or p53 K317R thymocytes was determined. We found 102 proteins to be significantly affected by IR in the wild type thymocytes, including several whose expression has been shown to be directly regulated by p53. When the effects of IR in the wild type and p53 K317R samples were compared, 46 proteins were found to be differently affected (p < 0.05). The p53 K317R mutation has widespread effects on specific protein levels following IR, including the levels of proteins involved in apoptosis, transcription, and translation. Pathway analysis of the differently regulated proteins suggests an increase in p53 activity in the p53 K317R thymocytes as well as a decrease in tumor necrosis factor ␣ signaling. These results suggest that acetylation of Lys-317 modulates the functions of p53 and influences the cross-talk between

Protein Carbonyl Formation in Response to Propiconazole-Induced Oxidative Stress

“…Although the carbonylation of proteins is generally thought to be a random and stochastic process, the proteins carbonylated by propiconazole treatment have inter-relationships as shown in Figure . This network was generated by unsupervised network analysis using Ingenuity Pathway Analyses, a knowledge-based pathways database program that has been used to discover insights in experimental data. , The network reveals interrelationships of proteins linked to central hubs: HNF4A, (hepatocyte nuclear factor 4, alpha), which binds to DNA as a homodimer and controls the expression of hepatic several genes; Fos (v-fos FBJ murine osteosarcoma viral oncogene homologue), a protein implicated as a regulator of cell proliferation, differentiation, apoptotic cell death and transformation; CYCS (cytochrome c, somatic); and PXN (paxillin), a cytoskeletal protein involved in Actin-membrane attachment at sites of cell adhesion tothe extracellular matrix. Among the 17 carbonylated proteins identified, four proteins are mitochondrial proteins (pyruvate carboxylase, ubiquinol-cytochrome c reductase complex core protein 1, succinyl-CoA ligase beta chain and aldehyde dehydrogenase mitochondrial precursor), and the remaining 13 proteins are mainly cytoplasmic proteins (with some linked to the cell membrane).…”

Proteomic Changes in Mouse Spleen after Radiation-Induced Injury and its Modulation by Gamma-Tocotrienol

“…Since in vitro cellular studies alone may not be sufficient to explain the proteomic alterations in complex tissues, using a global high-throughput proteomics approach offers several advantages for advancing the field of radiation biology (20, 22, 24). Radioproteomics is a powerful tool for comparing irradiated and normal tissues to identify organ-specific protein markers of radiation-induced tissue injury (20, 22, 24, 30, 31). There are previously published studies on radioproteomics in various mouse tissues/organs, including brain, lung, spleen, kidney and intestine (20, 32, 33).…”