Live-cell phenotypic-biomarker microfluidic assay for the risk stratification of cancer patients via machine learning.

The risk stratification of prostate cancer and breast cancer tumours from patients relies on histopathology, selective genomic testing, or on other methods employing fixed formalin tissue samples. However, static biomarker measurements from bulk fixed-tissue samples provide limited accuracy and actionability. Here, we report the development of a live-primary-cell phenotypic-biomarker assay with single-cell resolution, and its validation with prostate cancer and breast cancer tissue samples for the prediction of post-surgical adverse pathology.

Modulation of receptor dynamics by the regulator of G protein signaling Sst2.

G protein-coupled receptor (GPCR) signaling is fundamental to physiological processes such as vision, the immune response, and wound healing. In the budding yeast Saccharomyces cerevisiae, GPCRs detect and respond to gradients of pheromone during mating. After pheromone stimulation, the GPCR Ste2 is removed from the cell membrane, and new receptors are delivered to the growing edge.

Signal inhibition by a dynamically regulated pool of monophosphorylated MAPK.

Protein kinases regulate a broad array of cellular processes and do so through the phosphorylation of one or more sites within a given substrate. Many protein kinases are themselves regulated through multisite phosphorylation, and the addition or removal of phosphates can occur in a sequential (processive) or a stepwise (distributive) manner. Here we measured the relative abundance of the monophosphorylated and dual-phosphorylated forms of Fus3, a member of the mitogen-activated protein kinase (MAPK) family in yeast.

RGS proteins and septins cooperate to promote chemotropism by regulating polar cap mobility.

Background: Septins are well known to form a boundary between mother and daughter cells in mitosis, but their role in other morphogenic states is poorly understood.

Results: Using microfluidics and live-cell microscopy, coupled with new computational methods for image analysis, we investigated septin function during pheromone-dependent chemotropic growth in yeast. We show that septins colocalize with the regulator of G protein signaling (RGS) Sst2, a GTPase-activating protein that dampens pheromone receptor signaling.

Cellular noise suppression by the regulator of G protein signaling Sst2.

G proteins and their associated receptors process information from a variety of environmental stimuli to induce appropriate cellular responses. Generally speaking, each cell in a population responds within defined limits, despite large variation in the expression of protein signaling components. Therefore, we postulated that noise suppression is encoded within the signaling system.

Guanine nucleotide-binding protein (Gα) endocytosis by a cascade of ubiquitin binding domain proteins is required for sustained morphogenesis and proper mating in yeast.

Heterotrimeric G proteins are well known to transmit signals from cell surface receptors to intracellular effector proteins. There is growing appreciation that G proteins are also present at endomembrane compartments, where they can potentially interact with a distinct set of signaling proteins. Here, we examine the cellular trafficking function of the G protein α subunit in yeast, Gpa1.

Regulation of yeast G protein signaling by the kinases that activate the AMPK homolog Snf1.

Extracellular signals, such as nutrients and hormones, cue intracellular pathways to produce adaptive responses. Often, cells must coordinate their responses to multiple signals to produce an appropriate outcome. We showed that components of a glucose-sensing pathway acted on components of a heterotrimeric guanine nucleotide-binding protein (G protein)-mediated pheromone signaling pathway in the yeast Saccharomyces cerevisiae.