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Seale, B.

Publications and source records attributed to Seale, B..

3 recordsLinked to original sources

Stress Granules Underlie Acute Myeloid Leukemia Stem Cell Survival and Stress Adaptation

The link between cancer maintenance and an ability to sustain continued growth through stresses conferred by the cancer state itself is growing. However, there are significant gaps in our understanding of how this stress is managed, particularly at the level of cancer initiating cells. Here, we identify proteins comprising the dynamic, stress-adaptive ribonucleoprotein complexes known as stress granules (SG) to be enriched among the factors essential for leukemic stem cell (LSC)-driven leukemic propagation. Focusing on core SG nucleator G3BP1, we dissect the role of SGs in human acute myeloid leukemia (AML), their targetability, and the mechanisms they govern to uncover a novel propensity for AML, and in particular LSC-enriched fractions, to prime the expression of SG components, form SGs with greater fidelity and to be reliant on their establishment and continued integrity for LSC maintenance. We further unveil the transcript and protein interactome of G3BP1 in the AML context and show that consolidated control of innate immune signaling, and apoptosis repression is executed through regional binding specificity of G3BP1 to highly structured 3UTRs and cooperation with the RNA helicase UPF1 to mediate transcript decay in SGs. Altogether our findings advance novel fundamental principles of stress adaptation exploited in AML and LSCs that may extend to other cancers and uncover SGs as a novel axis for therapy development.

cancer biology↗

Dynamic extracellular proximal interaction profiling reveals Low-Density Lipoprotein Receptor as a new Epidermal Growth Factor signaling pathway component

Plasma membrane proteins are critical mediators of cell-cell and cell-environment interactions, pivotal in intracellular signal transmission vital for cellular functionality. Proximity-dependent biotinylation approaches such as BioID combined with mass spectrometry have begun illuminating the landscape of proximal protein interactions within intracellular compartments. However, their deployment in studies of the extracellular environment remains scarce. Here, we present extracellular TurboID (ecTurboID), a method designed to profile cell surface interactions in living cells on short timescales. We first report on the careful optimization of experimental and data analysis strategies that enable the capture of extracellular protein interaction information. Leveraging the ecTurboID technique, we unveiled the proximal interactome of multiple plasma membrane proteins, notably the epidermal growth factor receptor (EGFR). This led to identifying the low-density lipoprotein receptor (LDLR) as a newfound extracellular protein associating with EGFR, contingent upon the presence of the EGF ligand. We showed that 15 minutes of EGF stimulation induced LDLR localization to the plasma membrane to associate with proteins involved in EGFR regulation. This modified proximity labelling methodology allows us to dynamically study the associations between plasma membrane proteins in the extracellular environment. One Sentence SummaryWe developed extracellular TurboID (ecTurboID) as a new proximity dependent biotinylation approach that can capture dynamic interactions at the cell surface, identifying Low-Density Lipoprotein Receptor as a new ligand-dependent extracellular partner of Epidermal Growth Factor Receptor.

molecular biology↗

The petrosal and basicranial morphology of Protoceras celer

Protoceratids are an extinct family of endemic North American artiodactyls. The phylogenetic position of protoceratids in relation to camelids and ruminants has been contentious for over a century. The petrosal morphology of basal (Leptotragulus) and derived (Syndyoceras) protoceratids has suggested that protoceratids are closely related to ruminants, whereas a prior description of a disarticulated intermediate protoceratid petrosal (Protoceras celer) indicated that protoceratids were closely related to camelids. This contradictory evidence implied that there were several character reversals within the protoceratid lineage and brought into question the utility of basicranial characters in artiodactyl phylogenetics. Here, we provide descriptions of an additional P. celer petrosal. The descriptions are based on data produced by computed tomography scans, which allowed us to image the petrosal in situ in the skull. Our results indicate that the petrosal morphology of P. celer is similar to that of other protoceratids, implying that, contrary to previous evidence, petrosal morphology is conserved within the Protoceratidae.

paleontology↗