Mutation of RGA1, which encodes a putative GTPase-activating protein for the polarity-establishment protein Cdc42p, activates the pheromone-response pathway in the yeast Saccharomyces cerevisiae.

We have selected yeast mutants that exhibit a constitutively active pheromone-response pathway in the absence of the beta subunit of the trimeric G protein. Genetic analysis of one such mutant revealed that it contained recessive mutations in two distinct genes, both of which contributed to the constitutive phenotype. One mutation identifies the RGA1 locus (Rho GTPase activating protein), which encodes a protein with homology to GAP domains and to LIM domains. Deletion of RGA1 is sufficient to activate the pathway in strains lacking the G beta subunit. Moreover, in wild-type strains, deletion of RGA1 increases signaling in the pheromone pathway, whereas over-expression of RGA1 dampens signaling, demonstrating that Rga1p functions as a negative regulator of the pheromone response pathway. The second mutation present in the original mutant proved to be an allele of a known gene, PBS2, which encodes a putative protein kinase that functions in the high osmolarity stress pathway. The pbs2 mutation enhanced the rga1 mutant phenotype, but by itself did not activate the pheromone pathway. Genetic and two-hybrid analyses indicate that an important target of Rga1p is Cdc42p, a p21 GTPase required for polarity establishment and bud emergence. This finding coupled with recent experiments with mammalian and yeast cells indicating that Cdc42p can interact with and activate Ste20p, a protein kinase that operates in the pheromone pathway, leads us to suggest that Rga1p controls the activity of Cdc42p, which in turn controls the magnitude of signaling in the pheromone pathway via Ste20p

A Happy Abundance : Tales, Memoirs and More Past and Present in Wayne, Maine

https://digitalmaine.com/wayne_books/1002/thumbnail.jp

Tumour-derived GM-CSF promotes granulocyte immunosuppression in mesothelioma patients

Abstract Purpose: The cross-talk between tumor cells, myeloid cells, and T cells can play a critical role in tumor pathogenesis and response to immunotherapies. Although the etiology of mesothelioma is well understood, the impact of mesothelioma tumor cells on the surrounding immune microenvironment is less well studied. In this study, the effect of the mesothelioma tumor microenvironment on circulating and infiltrating granulocytes and T cells is investigated. Experimental Design: Tumor tissues and peripheral blood from mesothelioma patients were evaluated for presence of granulocytes, which were then tested for their T-cell suppression potential. Different cocultures of granulocytes and/or mesothelioma tumor cells and/or T cells were set up to identify the mechanism of T-cell inhibition. Results: Analysis of human tumors showed that the mesothelioma microenvironment is enriched in infiltrating granulocytes, which inhibit T-cell proliferation and activation. Characterization of the whole blood at diagnosis identified similar, circulating, immunosuppressive CD11b+CD15+HLADR− granulocytes at increased frequency compared with healthy controls. Culture of healthy-donor granulocytes with human mesothelioma cells showed that GM-CSF upregulates NOX2 expression and the release of reactive oxygen species (ROS) from granulocytes, resulting in T-cell suppression. Immunohistochemistry and transcriptomic analysis revealed that a majority of mesothelioma tumors express GM-CSF and that higher GM-CSF expression correlated with clinical progression. Blockade of GM-CSF with neutralizing antibody, or ROS inhibition, restored T-cell proliferation, suggesting that targeting of GM-CSF could be of therapeutic benefit in these patients. Conclusions: Our study presents the mechanism behind the cross-talk between mesothelioma tumors and the immune microenvironment and indicates that targeting GM-CSF could be a novel treatment strategy to augment immunotherapy in patients with mesothelioma. Clin Cancer Res; 24(12); 2859–72. ©2018 AACR.</jats:p

Building Your Programs 20 Minutes at a Time: Book 3

This archival publication may not reflect current scientific knowledge or recommendations. Current information available from the University of Minnesota Extension: https://www.extension.umn.edu.This is the third book in a collection of tools for building reflection into learning settings. This “sequel” offers 28 new activities that will help users intentionally plan for enhancing program quality through reflection, participatory evaluation, engagement and leadership skill building. Research on youth program quality, brain-based learning, and social-emotional learning all point to the importance of reflection as essential to the learning process. This resource book will help you build skills for facilitating reflection with youth and adult groups through an experiential learning model. It offers a brief overview of experiential learning and youth program quality research, along with facilitator tips and additional resources

A Happy Abundance : Tales, Memoirs and More Past and Present in Wayne, Maine

https://digitalmaine.com/wayne_books/1002/thumbnail.jp