Epithelial-mesenchymal plasticity contributes to many biological processes, including tumor progression. Various epithelial-mesenchymal transition (EMT) responses have been reported and no common, EMT-defining gene expression program has been identified. Here, we have performed a comparative analysis of the EMT response, leveraging highly multiplexed singlecell RNA sequencing (scRNA-seq) to measure expression profiles of 103,999 cells from 960 samples, comprising 12 EMT time course experiments and independent kinase inhibitor screens for each. We demonstrate that the EMT is vastly context specific, with an average of only 22% of response genes being shared between any two conditions, and over half of all response genes were restricted to 1-2 time course experiments. Further, kinase inhibitor screens revealed signaling dependencies and modularity of these responses. These findings suggest that the EMT is not simply a single, linear process, but is highly variable and modular, warranting quantitative frameworks for understanding nuances of the transition.

The Drosophila gene product Wingless (Wg) is a secreted glycoprotein and a member of the Wnt gene family. Genetic analysis of Drosophila epidermal development has defined a putative paracrine Wg signalling pathway involving the zeste‐white 3/shaggy (zw3/sgg) gene product. Although putative components of Wg‐ (and by inference Wnt‐) mediated signalling pathways have been identified by genetic analysis, the biochemical significance of most factors remains unproven. Here we show that in mouse 10T1/2 fibroblasts the activity of glycogen synthase kinase‐3 (GSK‐3), the murine homologue of Zw3/Sgg, is inactivated by Wg. This occurs through a signalling pathway that is distinct from insulin‐mediated regulation of GSK‐3 in that Wg signalling to GSK‐3 is insensitive to wortmannin. Additionally, Wg‐induced inactivation of GSK‐3 is sensitive to both the protein kinase C (PKC) inhibitor Ro31–8220 and prolonged pre‐treatment of 10T1/2 fibroblasts with phorbol ester. These findings provide the first biochemical evidence in support of the genetically defined pathway from Wg to Zw3/Sgg, and suggest a previously uncharacterized role for a PKC upstream of GSK‐3/Zw3 during Wnt/Wg signal transduction.

Axin promotes the phosphorylation of beta-catenin by GSK-3beta, leading to beta-catenin degradation. Wnt signals interfere with beta-catenin turnover, resulting in enhanced transcription of target genes through the increased formation of beta-catenin complexes containing TCF transcription factors. Little is known about how GSK-3beta-mediated beta-catenin turnover is regulated in response to Wnt signals. We have explored the relationship between Axin and Dvl-2, a member of the Dishevelled family of proteins that function upstream of GSK-3beta. Expression of Dvl-2 activated TCF-dependent transcription. This was blocked by co-expression of GSK-3beta or Axin. Expression of a 59 amino acid GSK-3beta-binding region from Axin strongly activated transcription in the absence of an upstream signal. Introduction of a point mutation into full-length Axin that prevented GSK-3beta binding also generated a transcriptional activator. When co-expressed, Axin and Dvl-2 co-localized within expressing cells. When Dvl-2 localization was altered using a C-terminal CAAX motif, Axin was also redistributed, suggesting a close association between the two proteins, a conclusion supported by co-immunoprecipitation data. Deletion analysis suggested that Dvl-association determinants within Axin were contained between residues 603 and 810. The association of Axin with Dvl-2 may be important in the transmission of Wnt signals from Dvl-2 to GSK-3beta.

Services comprise an ever‐expanding source of employment in the world's economies and are of significant interest to both academicians and practitioners. In this study, historical perspectives from which to view service typologies are provided and four decades of service typologies are chronicled. The interest in services demonstrated by academicians is tracked over time as are the purposes for which typologies have been developed. A unified schematic representation of services is developed in which the common themes underlying service typology development are identified from both a macro and micro level. Based on this study, areas for future research are identified.