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Biology subjects

Old, W.

Publications and source records attributed to Old, W..

3 recordsLinked to original sources

eIF3d and eIF3e mediate selective translational control of hypoxia that can be inhibited by novel small molecules

Exposure to hypoxia is linked to increased cellular plasticity and enhanced metastasis; effects which are primarily attributed to the transcriptional activation of large gene programs downstream of hypoxia inducible factors (HIFs). However, translational effects in hypoxia, that likely precede transcriptional effects, have remained largely unexplored. Using ribosome-profiling, we uncovered a selective translational response in acute hypoxia that is eIF3d/eIF3e-dependent and controls downstream hypoxic responses including HIF1a accumulation and cellular invasion. We further demonstrated that eIF3e copy number and an eIF3e-expression signature are associated with worsened outcomes for breast cancer patients. Finally, we identified a class of novel small molecules that target eIF3e specifically, reducing the translational response to hypoxia and to ER stress, another stressor that is dependent on eIF3d/eIF3e-mediated translation. Our data uncover critical functions for eIF3d/eIF3e in the hypoxic response and identify a potential means to inhibit stress-induced translation, and potentially plasticity and metastasis, mediated by eIF3e.

cancer biology↗

Proteomic analysis of microtubule inner proteins (MIPs) in Rib72 null Tetrahymena cells reveals functional MIPs

Motile cilia and flagella are built from stable populations of doublet microtubules that comprise their axonemes. Their unique stability is brought about, at least in part, by a network of Microtubule Inner Proteins (MIPs) found in the lumen of their doublet microtubules. Rib72A and Rib72B were identified as microtubule inner proteins (MIPs) in the motile cilia of Tetrahymena thermophila. Loss of these proteins leads to ciliary defects and loss of multiple MIPs. We performed mass spectrometry coupled with proteomic analysis and bioinformatics to identify the MIPs lost in RIB72A/B knockout (KO) Tetrahymena cells. From this analysis we identified a number of candidate MIPs and pursued one, Fap115, for functional characterization. We find that loss of Fap115 results in disrupted cell swimming and aberrant ciliary beating. Cryo-electron tomography reveals that Fap115 localizes to MIP6a in the A-tubule of the doublet microtubules. Overall, our results highlight the complex relationship between MIPs, ciliary structure, and ciliary function.

molecular biology↗

Unexpected Early Proteomic Changes in Alzheimer’s Disease Model Mice Synaptosomes

We have employed label-free quantitative proteomics of wild-type and Alzheimers disease (AD) model mice synaptosomes to investigate proteomic changes occurring during AD progression as a prelude to analysis in humans. More than 4000 proteins were analyzed using multiple analysis tools and statistical criteria. Pathway enrichment identified numerous pathways consistent with the current AD knowledge base, including dysregulation of Glutamate Receptor Signaling, Synaptic Long Term Potentiation and Depression, Rho and Rac Signaling, Calcium Signaling, and Oxidative Phosphorylation and Mitochondrial Dysfunction. Additionally, the data demonstrate that a large number of changes occur in the proteome very early relative to the onset of both traditional disease markers such as amyloid accumulation, tau phosphorylation and cognitive dysfunction. These early changes include a number of dysregulated proteins that have novel associations with AD progression. These results reinforce the importance of mechanistic investigations in early disease progression long before the classical markers of Alzheimers disease are observed.

neuroscience↗