Immune cells display multiple cell surface receptors that integrate signals for survival, proliferation, migration, and degranulation. Here, immunogold labeling is used to map the plasma membrane distributions of two separate receptors, the N-formyl peptide receptor (FPR) and the high-affinity IgE receptor (FRI). We show that the FPR forms signaling clusters in response to monovalent ligand. These domains recruit
The Finite Element Method (FEM) is a numerical technique widely used in finding approximate solutions for many scientific and engineering problems. The Data Assembly (DA) stage in FEM can take up to 50% of the total FEM execution time. Accelerating DA with Graphics Processing Units (GPUs) presents challenges due to DA's mixed compute-intensive and memory-intensive workloads. This paper uses a representative finite element mini-application to explore DA acceleration on CPU+GPU platforms. Implementations based on different thread, kernel and task design approaches are developed and compared. Their performance and energy consumption are measured on four CPU+GPU and two CPU only platforms. The results show that (i) the performance and energy for different implementations on the same platform can vary significantly but the performance and energy trends are the same, and (ii) there exist performance and energy tradeoffs across some platforms if the best implementation is chosen for each of the platforms.
The high affinity IgE receptor (FcεRI) of mast cells and basophils binds circulating IgE with sub‐nanomolar affinity. Crosslinking of IgE‐FcεRI complexes by multivalent allergen initiates a complex signaling cascade that leads to the release of inflammatory mediators. In order to study the dynamics of FcεRI signaling, we have generated two novel quantum dot (QD) based probes: monovalent QD‐IgE (binds FcεRI without crosslinking) and polyvalent 2,4‐dinitrophenol (DNP)‐QD (crosslinks DNP‐specific IgE). Through single QD tracking on the apical membrane of RBL‐2H3 cells, we observe a two‐fold decrease in the diffusion coefficient of IgE‐FcεRI complexes in the presence of saturating (dark) IgE‐FcεRI, suggesting homotypic interactions. By simultaneously tracking QD‐IgE and DNP‐QD, we observe that, at low allergen levels, DNP‐QD crosslinked receptors remain mobile, suggesting that receptor immobilization is not critical for signal initiation. Mathematical models incorporating these data show that slower diffusion rates of nearby receptors initiate clustering consistent with the distribution of immunolabeled receptors seen in electron micrographs. Taken together, these data indicate a mechanism through which FcεRI receptors maintain proximity and enhance the probability of signaling complex formation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.