The Professional Identity of STEM Faculty as Instructors of Course-based Research Experiences.

The professional identity of scientists has historically been cultivated to value research over teaching, which can undermine initiatives that aim to reform science education. Course-Based Research Experiences (CRE) and the inclusive Research and Education Communities (iREC) are two successful and impactful reform efforts that integrate research and teaching. The aim of this study is to explicate the professional identity of instructors who implement a CRE within an established iREC and to explore how this identity contributes to the success of these programs.

Structural and mechanistic insights into the transport of aristolochic acids and their active metabolites by human serum albumin.

Aristolochic acids I and II (AA-I/II) are carcinogenic principles of Aristolochia plants, which have been employed in traditional medicinal practices and discovered as food contaminants. While the deleterious effects of AAs are broadly acknowledged, there is a dearth of information to define the mechanisms underlying their carcinogenicity. Following bioactivation in the liver, N-hydroxyaristolactam and N-sulfonyloxyaristolactam metabolites are transported via circulation and elicit carcinogenic effects by reacting with cellular DNA.

Models of Classroom Assessment for Course-Based Research Experiences.

Course-based research pedagogy involves positioning students as contributors to authentic research projects as part of an engaging educational experience that promotes their learning and persistence in science. To develop a model for assessing and grading students engaged in this type of learning experience, the assessment aims and practices of a community of experienced course-based research instructors were collected and analyzed. This approach defines four aims of course-based research assessment - 1) Assessing Laboratory Work and Scientific Thinking; 2) Evaluating Mastery of Concepts, Quantitative Thinking and Skills; 3) Appraising Forms of Scientific Communication; and 4) Metacognition of Learning - along with a set of practices for each aim.

Prophage-mediated defence against viral attack and viral counter-defence.

Temperate phages are common, and prophages are abundant residents of sequenced bacterial genomes. Mycobacteriophages are viruses that infect mycobacterial hosts including Mycobacterium tuberculosis and Mycobacterium smegmatis, encompass substantial genetic diversity and are commonly temperate. Characterization of ten Cluster N temperate mycobacteriophages revealed at least five distinct prophage-expressed viral defence systems that interfere with the infection of lytic and temperate phages that are either closely related (homotypic defence) or unrelated (heterotypic defence) to the prophage.

RNA-induced silencing attenuates G protein-mediated calcium signals.

Phospholipase Cβ (PLCβ) is activated by G protein subunits in response to environmental stimuli to increase intracellular calcium. In cells, a significant portion of PLCβ is cytosolic, where it binds a protein complex required for efficient RNA-induced silencing called C3PO (component 3 promoter of RISC). Binding between C3PO and PLCβ raises the possibility that RNA silencing activity can affect the ability of PLCβ to mediate calcium signals.

Phospholipase Cβ connects G protein signaling with RNA interference.

Phosphoinositide-specific-phospholipase Cβ (PLCβ) is the main effector of Gαq stimulation which is coupled to receptors that bind acetylcholine, bradykinin, dopamine, angiotensin II as well as other hormones and neurotransmitters. Using a yeast two-hybrid and other approaches, we have recently found that the same region of PLCβ that binds Gαq also interacts with Component 3 Promoter of RNA induced silencing complex (C3PO), which is required for efficient activity of the RNA-induced silencing complex. In purified form, C3PO competes with Gαq for PLCβ binding and at high concentrations can quench PLCβ activation.

High pressure promotes alpha-synuclein aggregation in cultured neuronal cells.

α-Synuclein is found in plaques associated with Parkinson's and other neurodegenerative diseases. Changes in α-synuclein oligomerization are thought to give rise to nucleation of neurodegenerative plaques. Here, we investigated the effect of hydrostatic pressure on the aggregation of α-synuclein in cultured neuronal cells.

Comparative genomics of Cluster O mycobacteriophages.

Mycobacteriophages--viruses of mycobacterial hosts--are genetically diverse but morphologically are all classified in the Caudovirales with double-stranded DNA and tails. We describe here a group of five closely related mycobacteriophages--Corndog, Catdawg, Dylan, Firecracker, and YungJamal--designated as Cluster O with long flexible tails but with unusual prolate capsids. Proteomic analysis of phage Corndog particles, Catdawg particles, and Corndog-infected cells confirms expression of half of the predicted gene products and indicates a non-canonical mechanism for translation of the Corndog tape measure protein.

A broadly implementable research course in phage discovery and genomics for first-year undergraduate students.

Unlabelled: Engaging large numbers of undergraduates in authentic scientific discovery is desirable but difficult to achieve. We have developed a general model in which faculty and teaching assistants from diverse academic institutions are trained to teach a research course for first-year undergraduate students focused on bacteriophage discovery and genomics. The course is situated within a broader scientific context aimed at understanding viral diversity, such that faculty and students are collaborators with established researchers in the field.

Linking alpha-synuclein properties with oxidation: a hypothesis on a mechanism underling cellular aggregation.

α-Synuclein is a small, natively unstructured protein with propensity to aggregate. α-Synuclein fibrils are major components of Lewy bodies that are hallmarks of many neurodegenerative diseases. The solution properties and aggregation behavior of α-synuclein has been well characterized, but despite numerous studies that address the role of α-synuclein in cells, a clear physiological function of this protein remains a mystery.

Defining the oligomerization state of γ-synuclein in solution and in cells.

γ-Synuclein is expressed at high levels in neuronal cells and in multiple invasive cancers. Like its family member α-synuclein, γ-synuclein is thought to be natively unfolded but does not readily form fibrils. The function of γ-synuclein is unknown, but we have found that it interacts strongly with the enzyme phospholipase Cβ (PLCβ), altering its interaction with G proteins.

γ-Synuclein interacts with phospholipase Cβ2 to modulate G protein activation.

Phospholipase Cβ2 (PLC β2) is activated by G proteins and generates calcium signals in cells. PLCβ2 is absent in normal breast tissue, but is highly expressed in breast tumors where its expression is correlated with the progression and migration of the tumor. This pattern of expression parallels the expression of the breast cancer specific gene protein 1 which is also known as γ-synuclein.

Measuring fast calcium fluxes in cardiomyocytes.

Cardiomyocytes have multiple Ca(2+) fluxes of varying duration that work together to optimize function (1,2). Changes in Ca(2+) activity in response to extracellular agents is predominantly regulated by the phospholipase Cβ- Gα(q;) pathway localized on the plasma membrane which is stimulated by agents such as acetylcholine (3,4). We have recently found that plasma membrane protein domains called caveolae(5,6) can entrap activated Gα(q;)(7).

Evidence for a fence that impedes the diffusion of phosphatidylinositol 4,5-bisphosphate out of the forming phagosomes of macrophages.

To account for the many functions of phosphatidylinositol 4,5-bisphosphate (PIP(2)), several investigators have proposed that there are separate pools of PIP(2) in the plasma membrane. Recent experiments show the surface concentration of PIP(2) is indeed enhanced in regions where phagocytosis, exocytosis, and cell division occurs. Kinases that produce PIP(2) are also concentrated in these regions.

A dynamic model of membrane-bound phospholipase Cβ2 activation by Gβγ subunits.

Phospholipase C (PLC) β2, a well studied member of the family of enzymes that catalyze the hydrolysis of the membrane lipid phosphatidylinositol 4,5-bisphosphate (PIP₂) into secondary messengers, can be activated by the Gβγ subunits of heterotrimeric G-proteins in a manner that depends on the presence and composition of the associated phospholipid membrane surface. The N-terminal pleckstrin homology (PH) domain of PLCβ2 mediates both the response to Gβγ and membrane binding, but how these interactions are coupled to yield an activated catalytic core remains unknown. Here we propose a mechanism based on molecular models of truncated PLCβ2 in its activated form complexed with Gβγ and in the catalytically inactive/membrane-bound form, obtained with the application of protein-protein docking algorithms and coarse-grained molecular dynamics simulations.

Modulation of Ca²+ activity in cardiomyocytes through caveolae-Gαq interactions.

Cardiomyocytes have a complex Ca(2+) behavior and changes in this behavior may underlie certain disease states. Intracellular Ca(2+) activity can be regulated by the phospholipase Cβ-Gα(q) pathway localized on the plasma membrane. The plasma membranes of cardiomycoytes are rich in caveolae domains organized by caveolin proteins.

Differential response to morphine of the oligomeric state of μ-opioid in the presence of δ-opioid receptors.

Prolonged morphine treatment induces extensive desensitization of the μ-opioid receptor (μOR) which is the G-protein-coupled receptor that primarily mediates the cellular response to morphine. To date, the molecular mechanism underlying this process is unknown. Here, we have used live cell fluorescence imaging to investigate whether prolonged morphine treatment affects the physical environment of μOR, or its coupling with G-proteins, in two neuronal cell lines.

Wnt-dependent assembly of supermolecular Dishevelled-3-based complexes.

Dishevelled-3 (Dvl3) is a multivalent scaffold protein that is essential to Wnt signaling during development. Although Dvl-based punctae have been visualized by fluorescence microscopy; the physical nature and dynamic character of the such complexes are enigmatic. We use steric-exclusion chromatography, affinity pull-downs, proteomics and fluorescence correlation microscopy to characterize supermolecular Dvl3-based complexes of totipotent mouse F9 cells.

The small G protein Rac1 activates phospholipase Cdelta1 through phospholipase Cbeta2.

Rac1, which is associated with cytoskeletal pathways, can activate phospholipase Cbeta2 (PLCbeta2) to increase intracellular Ca(2+) levels. This increased Ca(2+) can in turn activate the very robust PLCdelta1 to synergize Ca(2+) signals. We have previously found that PLCbeta2 will bind to and inhibit PLCdelta1 in solution by an unknown mechanism and that PLCbeta2.

The effect of membrane domains on the G protein-phospholipase Cbeta signaling pathway.

The plasma membrane serves as a barrier to limit the exit and entry of components into and out of the cell, offering protection from the external environment. Communication between the cell and the external environment is mediated by multiple signaling pathways. While the plasma membrane was historically viewed as a lipid bilayer with freely diffusing proteins, the last decade has shown that the lipids and proteins in the plasma membrane are organized in a non-random manner, and that this organization can direct and modify various signaling pathways in the cell.

Novel endogenous peptide agonists of cannabinoid receptors.

Hemopressin (Hp), a 9-residue alpha-hemoglobin-derived peptide, was previously reported to function as a CB(1) cannabinoid receptor antagonist (1) . In this study, we report that mass spectrometry (MS) data from peptidomics analyses of mouse brain extracts identified N-terminally extended forms of Hp containing either three (RVD-Hpalpha) or two (VD-Hpalpha) additional amino acids, as well as a beta-hemoglobin-derived peptide with sequence similarity to that of hemopressin (VD-Hpbeta). Characterization of the alpha-hemoglobin-derived peptides using binding and functional assays shows that in contrast to Hp, which functions as a CB(1) cannabinoid receptor antagonist, both RVD-Hpalpha and VD-Hpalpha function as agonists.

Evidence for a second, high affinity Gbetagamma binding site on Galphai1(GDP) subunits.

It is well known that Galpha(i1)(GDP) binds strongly to Gbetagamma subunits to form the Galpha(i1)(GDP)-Gbetagamma heterotrimer, and that activation to Galpha(i1)(GTP) results in conformational changes that reduces its affinity for Gbetagamma subunits. Previous studies of G protein subunit interactions have used stoichiometric amounts of the proteins. Here, we have found that Galpha(i1)(GDP) can bind a second Gbetagamma subunit with an affinity only 10-fold weaker than the primary site and close to the affinity between activated Galpha(i1) and Gbetagamma subunits.

A self-scaffolding model for G protein signaling.

Activation of heterotrimeric G proteins is generally believed to induce dissociation of Galpha and Gbetagamma subunits, which are then free to bind to and change the catalytic activity of a variety of intracellular enzymes. We have previously found that in cells, Galphaq subunits remain complexed with its major effector, phospholipase Cbeta1, through the activation cycle. To determine whether this behavior may be operative in other systems, we carried out Förster resonance energy transfer studies and found that eYFP-Galphai and eCFP-Gbetagamma remain associated after stimulation in HEK293 cells.