Shielding the Enemy of the People : Protecting the Reporter\u27s Privilege in the Age of Social Media

President Donald Trump and his surrogates regularly belittle media outlets that publish articles critical of the administration. Arguably, no newsgathering practice has undergone more scrutiny from the Trump Administration than the use of unnamed sources. During this time, journalists must understand the extent to which the law will protect their reporting and their valuable anonymous sources. Almost forty years ago, the United States Supreme Court held in Branzburg v. Hayes, in 1972 that a general federal reporter’s privilege does not exist. Robust reporter shield laws exist in individual states, but these privileges largely lag behind the digital media revolution. When a large percentage of Americans digest news through social media resources like Facebook and Twitter, how can they distinguish between a journalist worthy of protection and an ordinary Facebook friend or Twitter follower? This Note tracks the history of anonymous reporting, discusses the development of the reporter’s privilege, and considers how to ensure protections for modern journalists. This Note argues that to best protect digital journalists and social media users, Congress should enact a federal reporter’s shield that protects journalistic acts, explicitly includes digital media, and requires an intent to disseminate information to the public

Fluorescence Correlation Spectroscopy as a Quantitative Tool Applied to Drug Delivery Model Systems

The delivery of drugs to cells is a very active area of research. Drugs are commonly believed to ameliorate illnesses. The targeted, controlled and/or enhanced uptake of the drug into cells is facilitated by loading the drug into carrier vehicles (nanoparticles, e.g.. micelles).The distribution of a drug over the nanoparticles used to deliver the drug to the targeted cells is of vital importance. It makes a difference, whether all nanoparticles carry the same amount of drug or whether a little amount of the nanoparticles carries a high proportion of the drug material and most nanoparticles carry no material. This depends on the method used to load the drugs into the carriers. Furthermore, the absolute amount of drug present in the nanoparticles and the absolute number of nanoparticles loaded with drug molecules is very important, because "dosis venum facit" [Paracelsus]. We present an approach to resolve these issues by optical means.If the drug is fluorescent or labeled with a fluorescent label, fluorescence correlation spectroscopy (FCS) can be used to determine quantitative size distributions with a (confocal) microscope. In order to determine absolute concentrations the spatial dimensions of the confocal observation volume have to be known. These can be obtained from numerical simulations using vectorial diffraction theory. The theoretical results have been compared with experimental results from FCS using the calibration dye Rhodamine 6G. In a straightforward procedure the results were corrected for adsorption effects and excellent agreement to the theory was foun

Uncovering the Role of IS in Business Model Innovation - A Taxonomy-driven Approach to Structure the Field

Business model innovations (BMIs) are one of the key activities organizations must undertake to survive and thrive. As information systems (IS) penetrate more and more aspects of life, they become an important factor affecting both the process and the outcome of business model innovations. The increased importance of IS in a growing number of industries has led various researchers to focus on examining the role of IS in innovation. However, these insights concentrate on process, product, and service innovations, while business model innovations encompass characteristics that are fundamentally different from these. Therefore, in this paper we use a rigorous taxonomy-building approach to uncover the distinct roles IS play in this important endeavor, employing a meta-perspective and drawing from documented empirical research on business model innovations. We found that IS act, first, as enablers of business model innovation, second, as capabilities in the business model innovation process, and third, as frames of reference for business model innovations. Our findings indicate that IS are thus both operand and operant resources in business model innovations. Hence, business managers must be aware of all of these roles, as they could have transformative impacts in every industry

Structural Basis for the Cooperation of Hsp110 and Hsp70 Molecular Chaperones in Protein Folding

Protein folding is a crucial process for cell survival. Only natively structured proteins can perform their essential biological functions. Although all structure-relevant information is principally encoded in the amino acid sequence of a protein, the efficient folding of many larger proteins depends on the assistance of molecular chaperones. These proteins bind reversibly to exposed hydrophobic sequences in folding intermediates, thereby preventing aggregation and supporting effective folding. The Hsp70 family proteins constitute key components of the cellular chaperone network in eukaryotes and bacteria. They are involved in diverse protein processing reactions, reaching from folding and assembly of nascent polypeptides to protein transport across membranes. Regular Hsp70s consist of an N-terminal nucleotide binding domain (NBD) and an allosterically coupled C-terminal substrate binding domain, which is further divided into a beta-sandwich domain and a three helix bundle domain (3HBD). Hsp70s perform their cellular functions through ATP-driven cycles of substrate binding and release: In the ATP state, peptide binding is dynamic. ATP hydrolysis results in a dramatic structural rearrangement, leading to a conformation in which hydrophobic peptide segments are locked between 3HBD and beta-sandwich domain. Thus, substrate proteins are stably bound in the ADP and apo state. This Hsp70 folding cycle is tightly controlled by a large complement of cochaperones. Whereas J-domain proteins recruit substrates and trigger ATP hydrolysis, nucleotide exchange factors (NEFs) accelerate ADP release. In eukaryotes, four evolutionarily unrelated classes of Hsp70 NEFs have been identified, among which Hsp110 homologs are most abundant. As judged by their conserved domain composition, Hsp110s derive from canonical Hsp70s, but have evolved into NEFs, preserving the ability to stabilize misfolded proteins in solution. In the present study, the cooperation of Hsp70 and Hsp110 molecular chaperones in protein folding was investigated. First, the crystal structure of a functional complex between the yeast Hsp110 homolog Sse1p and the NBD of human Hsp70 was determined. The structure was solved by selenium multiple wavelength anomalous diffraction and refined at 2.3 Å resolution to a crystallographic R-factor of 19.7 %. The structure of Sse1p is characterized by extended domain-domain interactions. Beta-sandwich domain and 3HBD are arranged along the NBD and point into opposite directions. Importantly, Sse1p has ATP bound, a prerequisite for efficient complex formation with Hsp70. In the complex, the NBD and 3HBD of Sse1p embrace the Hsp70 NBD, thereby opening the nucleotide binding cleft of Hsp70 and releasing ADP. In a subsequent mutational analysis, key features of the chaperone complex were targeted. Specifically, amino acid exchanges were introduced (i) in the areas of close surface contacts between Sse1p and Hsp70N, (ii) at the interfaces between individual Sse1p domains, (iii) in the nucleotide binding pocket of Sse1p, and (iv) at the putative substrate binding site in the beta-sandwich domain of Sse1p. Sse1p mutations affecting the interaction between the Hsp70 NBD and the Sse1p 3HBD strongly impaired Hsp70 complex formation and nucleotide exchange. Consistently, these Sse1p variants were less effective than wildtype (wt) Sse1p in supporting substrate release from Hsp70 and Hsp70-mediated refolding of thermally denatured firefly luciferase. In vivo, the respective sse1 mutations caused severe stress and a pronounced growth defect, likely because of reduced substrate flux through the Hsp70 machinery. Taken together, these results define nucleotide exchange on Hsp70 as the main function of Sse1p. Furthermore, they highlight the importance of the interaction between the Hsp70 NBD and the Sse1p 3HBD for the nucleotide exchange activity of Sse1p. No evidence was found for an ATP-driven, Hsp70-like conformational cycle of Sse1p. Mutations targeting the Sse1p inter-domain communication and the ATPase activity did not impair Sse1p function in vitro and in vivo. Mutations at the putative substrate binding cleft of Sse1p aggravated the functional defect of partially NEF-deficient Sse1p mutants in vitro and in vivo. Thus, direct substrate interactions mediated by the beta-sandwich domain may support Hsp70-assisted protein folding in addition to the nucleotide exchange function of Sse1p. According to our mutational analysis, Hsp110s contribute to Hsp70-assisted protein folding in two ways: Their major function is the acceleration of ADP dissociation from Hsp70 by stabilizing the Hsp70 NBD in an open conformation with low affinity for the nucleotide. Consequently, Hsp110s support the rapid conformational cycling of Hsp70 and thus efficient substrate binding and release. In addition, Hsp110s may directly interact with the unfolded substrate upon binding to Hsp70. By holding the misfolded protein chain, Hsp110s might cooperatively aid Hsp70 in remodeling the substrate via large-scale thermal motions of the Hsp70 PBD

Confound-leakage: confound removal in machine learning leads to leakage

BACKGROUND: Machine learning (ML) approaches are a crucial component of modern data analysis in many fields, including epidemiology and medicine. Nonlinear ML methods often achieve accurate predictions, for instance, in personalized medicine, as they are capable of modeling complex relationships between features and the target. Problematically, ML models and their predictions can be biased by confounding information present in the features. To remove this spurious signal, researchers often employ featurewise linear confound regression (CR). While this is considered a standard approach for dealing with confounding, possible pitfalls of using CR in ML pipelines are not fully understood. RESULTS: We provide new evidence that, contrary to general expectations, linear confound regression can increase the risk of confounding when combined with nonlinear ML approaches. Using a simple framework that uses the target as a confound, we show that information leaked via CR can increase null or moderate effects to near-perfect prediction. By shuffling the features, we provide evidence that this increase is indeed due to confound-leakage and not due to revealing of information. We then demonstrate the danger of confound-leakage in a real-world clinical application where the accuracy of predicting attention-deficit/hyperactivity disorder is overestimated using speech-derived features when using depression as a confound. CONCLUSIONS: Mishandling or even amplifying confounding effects when building ML models due to confound-leakage, as shown, can lead to untrustworthy, biased, and unfair predictions. Our expose of the confound-leakage pitfall and provided guidelines for dealing with it can help create more robust and trustworthy ML models

Tah1 helix-swap dimerization prevents mixed Hsp90 co-chaperone complexes

Specific co-chaperone adaptors facilitate the recruitment of client proteins to the Hsp90 system. Tah1 binds the C-terminal conserved MEEVD motif of Hsp90, thus linking an eclectic set of client proteins to the R2TP complex for their assembly and regulation by Hsp90. Rather than the normal complement of seven α-helices seen in other tetratricopeptide repeat (TPR) domains, Tah1 unusually consists of the first five only. Consequently, the methionine of the MEEVD peptide remains exposed to solvent when bound by Tah1. In solution Tah1 appears to be predominantly monomeric, and recent structures have failed to explain how Tah1 appears to prevent the formation of mixed TPR domain-containing complexes such as Cpr6-(Hsp90)2-Tah1. To understand this further, the crystal structure of Tah1 in complex with the MEEVD peptide of Hsp90 was determined, which shows a helix swap involving the fifth α-helix between two adjacently bound Tah1 molecules. Dimerization of Tah1 restores the normal binding environment of the bound Hsp90 methionine residue by reconstituting a TPR binding site similar to that in seven-helix-containing TPR domain proteins. Dimerization also explains how other monomeric TPR-domain proteins are excluded from forming inappropriate mixed co-chaperone complexes

CDK-dependent Hsp70 phosphorylation controls G1 cyclin abundance and cell-cycle progression

In budding yeast, the essential functions of Hsp70 chaperones Ssa1-4 are regulated through expression level, isoform specificity, and cochaperone activity. Suggesting a novel regulatory paradigm, we find that phosphorylation of Ssa1 T36 within a cyclin-dependent kinase (CDK) consensus site conserved among Hsp70 proteins alters cochaperone and client interactions. T36 phosphorylation triggers displacement of Ydj1, allowing Ssa1 to bind the G1 cyclin Cln3 and promote its degradation. The stress CDK Pho85 phosphorylates T36 upon nitrogen starvation or pheromone stimulation, destabilizing Cln3 to delay onset of S phase. In turn, the mitotic CDK Cdk1 phosphorylates T36 to block Cln3 accumulation in G2/M. Suggesting broad conservation from yeast to human, CDK-dependent phosphorylation of Hsc70 T38 similarly regulates Cyclin D1 binding and stability. These results establish an active role for Hsp70 chaperones as signal transducers mediating growth control of G1 cyclin abundance and activity

CDK-Dependent Hsp70 Phosphorylation Controls G1 Cyclin Abundance and Cell-Cycle Progression

In budding yeast, the essential functions of Hsp70 chaperones Ssa1–4 are regulated through expression level, isoform specificity, and cochaperone activity. Suggesting a novel regulatory paradigm, we find that phosphorylation of Ssa1 T36 within a cyclin-dependent kinase (CDK) consensus site conserved among Hsp70 proteins alters cochaperone and client interactions. T36 phosphorylation triggers displacement of Ydj1, allowing Ssa1 to bind the G1 cyclin Cln3 and promote its degradation. The stress CDK Pho85 phosphorylates T36 upon nitrogen starvation or pheromone stimulation, destabilizing Cln3 to delay onset of S phase. In turn, the mitotic CDK Cdk1 phosphorylates T36 to block Cln3 accumulation in G2/M. Suggesting broad conservation from yeast to human, CDK-dependent phosphorylation of Hsc70 T38 similarly regulates Cyclin D1 binding and stability. These results establish an active role for Hsp70 chaperones as signal transducers mediating growth control of G1 cyclin abundance and activity

Structural basis for phosphorylation-dependent recruitment of tel2 to hsp90 by pih1

Client protein recruitment to the Hsp90 system depends on cochaperones that bind the client and Hsp90 simultaneously and facilitate their interaction. Hsp90 involvement in the assembly of snoRNPs, RNA polymerases, PI3-kinase-like kinases, and chromatin remodeling complexes depends on the TTT (Tel2-Tti1-Tti2), and R2TP complexes-consisting of the AAA-ATPases Rvb1 and Rvb2, Tah1 (Spagh/RPAP3 in metazoa), and Pih1 (Pih1D1 in humans)-that together provide the connection to Hsp90. The biochemistry underlying R2TP function is still poorly understood. Pih1 in particular, at the heart of the complex, has not been described at a structural level, nor have the multiple protein-protein interactions it mediates been characterized. Here we present a structural and biochemical analysis of Hsp90-Tah1-Pih1, Hsp90-Spagh, and Pih1D1-Tel2 complexes that reveal a domain in Pih1D1 specific for binding CK2 phosphorylation sites, and together define the structural basis by which the R2TP complex connects the Hsp90 chaperone system to the TTT complex