The Fundamental Characteristics of a Translational Scientist.

Translational science is defined as the field of investigation focused on understanding the scientific and operational principles underlying each step of the translational process. Further development of the field is advanced by describing the key desirable characteristics of individuals who seek to uncover these principles to increase the efficiency and efficacy of translation. The members of Translation Together, a newly launched international collaborative effort to advance translational innovation, present here a consensus representation of the fundamental characteristics of a translational scientist. We invite all stakeholders to contribute in the ongoing efforts to develop the field and educate the next generation of translational scientists.

Application of a Dynamic Map for Learning, Communicating, Navigating, and Improving Therapeutic Development.

Drug discovery and development is commonly schematized as a "pipeline," and, although appreciated by drug developers to be a useful oversimplification, this cartology may perpetuate inaccurate notions of straightforwardness and is of minimal utility for process engineering to improve efficiency. To create a more granular schema, a group of drug developers, researchers, patient advocates, and regulators developed a crowdsourced atlas of the steps involved in translating basic discoveries into health interventions, annotated with the steps that are particularly prone to difficulty or failure. This Drug Discovery, Development, and Deployment Map (4DM), provides a network view of the process, which will be useful for communication and education to those new to the field, orientation and navigation of individual projects, and prioritization of technology development and re-engineering endeavors to improve efficiency and effectiveness. The 4DM is freely available for utilization, modification, and further development by stakeholders across the translational ecosystem.

The translational science training program at NIH: Introducing early career researchers to the science and operation of translation of basic research to medical interventions.

Translational science is an emerging field that holds great promise to accelerate the development of novel medical interventions. As the field grows, so does the demand for highly trained biomedical scientists to fill the positions that are being created. Many graduate and postdoctorate training programs do not provide their trainees with sufficient education to take advantage of this growing employment sector. To help better prepare the trainees at the National Institutes of Health for possible careers in translation, we have created the Translational Science Training Program (TSTP). The TSTP is an intensive 2- to 3-day training program that introduces NIH postdoctoral trainees and graduate students to the science and operation of turning basic research discoveries into a medical therapeutic, device or diagnostic, and also exposes them to the variety of career options in translational science. Through a combination of classroom teaching from practicing experts in the various disciplines of translation and small group interactions with pre-clinical development teams, participants in the TSTP gain knowledge that will aid them in obtaining a career in translational science and building a network to make the transition to the field. © 2016 by The International Union of Biochemistry and Molecular Biology, 45(1):13-24, 2017.

Putting translational science on to a global stage.

Global collaboration in translational science promises to accelerate the discovery, development and dissemination of new medical interventions. Here, we introduce a new international collaboration of translational science organizations and highlight our initial strategy to reduce or remove bottlenecks in translation.

The chemokine receptor CCR1 is constitutively active, which leads to G protein-independent, ß-arrestin-mediated internalization.

Activation of G protein-coupled receptors by their associated ligands has been extensively studied, and increasing structural information about the molecular mechanisms underlying ligand-dependent receptor activation is beginning to emerge with the recent expansion in GPCR crystal structures. However, some GPCRs are also able to adopt active conformations in the absence of agonist binding that result in the initiation of signal transduction and receptor down-modulation. In this report, we show that the CC-type chemokine receptor 1 (CCR1) exhibits significant constitutive activity leading to a variety of cellular responses. CCR1 expression is sufficient to induce inhibition of cAMP formation, increased F-actin content, and basal migration of human and murine leukocytes. The constitutive activity leads to basal phosphorylation of the receptor, recruitment of ß-arrestin-2, and subsequent receptor internalization. CCR1 concurrently engages Gαi and ß-arrestin-2 in a multiprotein complex, which may be accommodated by homo-oligomerization or receptor clustering. The data suggest the presence of two functional states for CCR1; whereas receptor coupled to Gαi functions as a canonical GPCR, albeit with high constitutive activity, the CCR1·ß-arrestin-2 complex is required for G protein-independent constitutive receptor internalization. The pertussis toxin-insensitive uptake of chemokine by the receptor suggests that the CCR1·ß-arrestin-2 complex may be related to a potential scavenging function of the receptor, which may be important for maintenance of chemokine gradients and receptor responsiveness in complex fields of chemokines during inflammation.

A novel approach to quantify G-protein-coupled receptor dimerization equilibrium using bioluminescence resonance energy transfer.

Along with other resonance energy transfer techniques, bioluminescence resonance energy transfer (BRET) has emerged as an important method for demonstrating protein-protein interactions in cells. In the field of G-protein-coupled receptors, including chemokine receptors, BRET has been widely used to investigate homo- and heterodimerization, a feature of their interactions that is emerging as integral to function and regulation. While demonstrating the existence of dimers for a given receptor proved to be fairly straightforward, quantitative comparisons of different receptors or mutants are nontrivial because of inevitable variations in the expression of receptor constructs. The uncontrollable parameters of the cellular expression machinery make amounts of transfected DNA extremely poor predictors for the expression levels of BRET donor and acceptor receptor constructs, even in relative terms. In this chapter, we show that properly accounting for receptor expression levels is critical for quantitative interpretation of BRET data. We also provide a comprehensive account of expected responses in all types of BRET experiments and propose a framework for uniform and accurate quantitative treatment of these responses. The framework allows analysis of both homodimer and heterodimer BRET data. The important caveats and obstacles for quantitative treatment are outlined, and the utility of the approach is illustrated by its application to the homodimerization of wild-type (WT) and mutant forms of the chemokine receptor CXCR4.

Structure of the unbound form of HIV-1 subtype A protease: comparison with unbound forms of proteases from other HIV subtypes.

The crystal structure of the unbound form of HIV-1 subtype A protease (PR) has been determined to 1.7 A resolution and refined as a homodimer in the hexagonal space group P6(1) to an R(cryst) of 20.5%. The structure is similar in overall shape and fold to the previously determined subtype B, C and F PRs. The major differences lie in the conformation of the flap region. The flaps in the crystal structures of the unbound subtype B and C PRs, which were crystallized in tetragonal space groups, are either semi-open or wide open. In the present structure of subtype A PR the flaps are found in the closed position, a conformation that would be more anticipated in the structure of HIV protease complexed with an inhibitor. The amino-acid differences between the subtypes and their respective crystal space groups are discussed in terms of the differences in the flap conformations.

The contribution of naturally occurring polymorphisms in altering the biochemical and structural characteristics of HIV-1 subtype C protease.

Fourteen subtype B and C protease variants have been engineered in an effort to study whether the preexistent baseline polymorphisms, by themselves or in combination with drug resistance mutations, differentially alter the biochemical and structural features of the subtype C protease when compared with those of subtype B protease. The kinetic studies performed in this work showed that the preexistent polymorphisms in subtype C protease, by themselves, do not provide for a greater level of resistance. Inhibition analysis with eight clinically used protease inhibitors revealed that the natural polymorphisms found in subtype C protease, in combination with drug resistance mutations, can influence enzymatic catalytic efficiency and inhibitor resistance. Structural analyses of the subtype C protease bound to nelfinavir and indinavir showed that these inhibitors form similar interactions with the residues in the active site of subtype B and C proteases. It also revealed that the naturally occurring polymorphisms could alter the position of the outer loops of the subtype C protease, especially the 60's loop.

Nitric oxide production by nurse shark (Ginglymostoma cirratum) and clearnose skate (Raja eglanteria) peripheral blood leucocytes.

Reactive nitrogen intermediates, such as nitric oxide (NO), are important immunomodulators in vertebrate immune systems, but have yet to be identified as mediators of host defence in any member of class Chondrichthyes, the cartilaginous fishes. In the present study, production of NO by nurse shark (Ginglymostoma cirratum) peripheral blood leucocytes (PBL) stimulated with bacterial cell wall lipopolysaccharide (LPS) was investigated. PBL were cultured for 24 to 96 h following stimulation with LPS at concentrations ranging from 0 to 25 microg ml(-1), in both serum-supplemented and serum-free culture conditions. Production of NO was measured indirectly using the Griess reaction, with maximal NO production occurring after 72 h using 10% FBS and 10 microg LPS ml(-1). Application of these culture conditions to PBL from another cartilaginous fish (clearnose skate, Raja eglanteria) resulted in a similar NO response. Addition of a specific inhibitor of inducible nitric oxide synthase (iNOS), L-N(6)-(1-iminoethyl)lysine (L-NIL), resulted in a significant decrease in the production of NO by PBL from both species.