Adam B. Castoreno
Harvard University
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Adam B. Castoreno.
Proceedings of the National Academy of Sciences of the United States of America | 2009
Thouis R. Jones; Anne E. Carpenter; Michael R. Lamprecht; Jason Moffat; Serena J. Silver; Jennifer K. Grenier; Adam B. Castoreno; Ulrike S. Eggert; David E. Root; Polina Golland; David M. Sabatini
Many biological pathways were first uncovered by identifying mutants with visible phenotypes and by scoring every sample in a screen via tedious and subjective visual inspection. Now, automated image analysis can effectively score many phenotypes. In practical application, customizing an image-analysis algorithm or finding a sufficient number of example cells to train a machine learning algorithm can be infeasible, particularly when positive control samples are not available and the phenotype of interest is rare. Here we present a supervised machine learning approach that uses iterative feedback to readily score multiple subtle and complex morphological phenotypes in high-throughput, image-based screens. First, automated cytological profiling extracts hundreds of numerical descriptors for every cell in every image. Next, the researcher generates a rule (i.e., classifier) to recognize cells with a phenotype of interest during a short, interactive training session using iterative feedback. Finally, all of the cells in the experiment are automatically classified and each sample is scored based on the presence of cells displaying the phenotype. By using this approach, we successfully scored images in RNA interference screens in 2 organisms for the prevalence of 15 diverse cellular morphologies, some of which were previously intractable.
Nature Chemical Biology | 2010
Adam B. Castoreno; Yegor Smurnyy; Angelica D Torres; Martha S. Vokes; Thouis R. Jones; Anne E. Carpenter; Ulrike S. Eggert
We report the discovery of small molecules that target the Rho pathway, a central regulator of cytokinesis, the final step in cell division. We have developed a method to target a small molecule screen towards a specific pathway, which should be widely applicable to study any signaling pathway. In a chemical genetic variant of a classical modifier screen, we used RNA interference (RNAi) to sensitize cells and identified small molecules that suppressed or enhanced the RNAi phenotype. We have discovered promising candidate molecules, which we named Rhodblock 1–8, and we identified the target of Rhodblock 6 as Rho kinase. Several Rhodblocks inhibit a function of the Rho pathway in cells: the correct localization of phosphorylated myosin light chain during cytokinesis. Rhodblocks differentially perturb Rho pathway proteins in cells and can be used to dissect the mechanism of the Rho pathway during cytokinesis.
ACS Chemical Biology | 2011
Adam B. Castoreno; Ulrike S. Eggert
Small molecules are important not only as therapeutics to treat disease but also as chemical tools to probe complex biological processes. The discovery of novel bioactive small molecules has largely been catalyzed by screening diverse chemical libraries for alterations in specific activities in pure proteins assays or in generating cell-based phenotypes. New approaches are needed to close the vast gap between the ability to study either single proteins or whole cellular processes. This Review focuses on the growing number of studies aimed at understanding in more detail how small molecules perturb particular signaling pathways and larger networks to yield distinct cellular phenotypes. This type of pathway-level analysis and phenotypic profiling provides valuable insight into mechanistic action of small molecules and can reveal off-target effects and improve our understanding of how proteins within a pathway regulate signaling.
ACS Chemical Biology | 2010
G. Ekin Atilla-Gokcumen; Adam B. Castoreno; Sofia Sasse; Ulrike S. Eggert
Cytokinesis is the last step in the cell cycle, where daughter cells finally separate. It is precisely regulated in both time and space to ensure that each daughter cell receives an equal share of DNA and other cellular materials. Chemical biology approaches have been used very successfully to study the mechanism of cytokinesis. In this review, we discuss the use of small molecule probes to perturb cytokinesis, as well as the role naturally occurring small molecule metabolites such as lipids play during cytokinesis.
Proceedings of the National Academy of Sciences of the United States of America | 2006
Vishal Trivedi; Shao C. Zhang; Adam B. Castoreno; Walter Stockinger; Eugenie C. Shieh; Jatin M. Vyas; Eva-Maria Frickel; Axel Nohturfft
An important role of IgG antibodies in the defense against microbial infections is to promote the ingestion and killing of microbes by phagocytes. Here, we developed in vivo and in vitro approaches to ask whether opsonization of particles with IgG enhances intracellular targeting of lysosomes to phagosomes. To eliminate the effect of IgG on the ingestion process, cells were exposed to latex beads at 15–20°C, which allows engulfment of both IgG-coated and uncoated beads but prevents the fusion of lysosomes with phagosomes. Upon shifting the temperature to 37°C, phagosomes containing IgG beads matured significantly faster into phagolysosomes as judged by colocalization with lysosomal markers. The IgG effect was independent of other particle-associated antigens or serum factors. Lysosome/phagosome attachment was also quantified biochemically with a cytosol-dependent scintillation proximity assay. Interactions were enhanced significantly in reactions containing cytosol from mouse macrophages that had been exposed to IgG-coated beads, indicating that IgG signaling modulates the cytosolic-targeting machinery. Similar results were obtained with cytosol from primary human monocytes, human U-937 histiocytic lymphoma cells and from Chinese hamster ovary (CHO) cells transfected with a human IgG (Fcγ) receptor. IgG-induced activation is shown to affect the actin-dependent tethering/docking stage of the targeting process and to proceed through a pathway involving protein kinase C. These results provide a rare example of an extracellular signal controlling membrane targeting on the level of tethering and docking. We propose that this pathway contributes to the role of antibodies in the protection against microbial infections.
Fems Microbiology Letters | 2003
Shahram Mori; Adam B. Castoreno; Martin E. Mulligan; Peter J. Lammers
Biochemical responses to cold and osmotic stresses overlap because each decreases the availability of free water. Since RNA-binding proteins are known to accumulate following cold stress and play key roles in regulating transcription termination, the effect of osmotic stress on expression of RNA-binding proteins was examined. The transcript levels of four genes encoding RNA-binding proteins (rbpA, rbpB, rbpC and rbpD) were monitored in Anabaena sp. PCC 7120 cultures supplemented with ammonium ions or growing under nitrogen-fixing conditions. Steady-state transcript levels of all four genes increased transiently in response to a temperature shift from 30 to 20 degrees C under both nitrogen regimes. Osmotic stress also enhanced rbpB, rbpC and rbpD gene expression in ammonium grown cultures. In the absence of a combined nitrogen source, osmotic stress repressed the short-term induction of rbp gene expression. The accumulation of RNA-binding proteins did not follow transcript levels, but remained high 24 h after stress initiation. It is concluded that nitrogen nutrition modulates the stress-responsive regulation of RNA-binding proteins in cyanobacteria, providing a potential mechanism to integrate environmental and developmental signals.
Archive | 2013
Natalia B. Nedelsky; Petric Kuballa; Adam B. Castoreno; Ramnik J. Xavier
Studies using human genetics have identified more than 160 loci that affect the risk of developing inflammatory bowel disease (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC). Several of these genes have been found to play key roles in the process of autophagy, a lysosome-based degradation pathway. Although historically considered to be a relatively nonselective process of degradation of cytosolic contents, autophagy has recently been revealed to have several selective and immune-specific functions that are relevant to the maintenance of intestinal homeostasis, including xenophagy, mitophagy, antigen presentation, secretion, and inflammasome regulation. In this chapter, we review the evidence that links autophagy-related genes, their immune-specific functions, and possible mechanisms of IBD pathogenesis. We summarize the basic molecular events underlying general and selective autophagy and present evidence suggesting possible pathogenic mechanisms revealed by studies of IBD-associated risk alleles of ATG16L1 and IRGM. Finally, we review chemical biology-based experimental approaches for identifying autophagy regulatory pathways that may have implications for the development of therapeutics.
Proceedings of the National Academy of Sciences of the United States of America | 2005
Adam B. Castoreno; Yan Wang; Walter Stockinger; Larissa A. Jarzylo; Hong Du; Joanne Pagnon; Eugenie C. Shieh; Axel Nohturfft
Molecular Biology of the Cell | 2006
Walter Stockinger; Shao C. Zhang; Vishal Trivedi; Larissa A. Jarzylo; Eugenie C. Shieh; William S. Lane; Adam B. Castoreno; Axel Nohturfft
Journal of Biological Chemistry | 2005
Yan Wang; Adam B. Castoreno; Walter Stockinger; Axel Nohturfft