Diversity of function and higher-order structure within HWE sensor histidine kinases.

Integral to the protein structure/function paradigm, oligomeric state is typically conserved along with function across evolution. However, notable exceptions such as the hemoglobins show how evolution can alter oligomerization to enable new regulatory mechanisms. Here, we examine this linkage in histidine kinases (HKs), a large class of widely distributed prokaryotic environmental sensors. While the majority of HKs are transmembrane homodimers, members of the HWE/HisKA2 family can deviate from this architecture as exemplified by our finding of a monomeric soluble HWE/HisKA2 HK (EL346, a photosensing light-oxygen-voltage [LOV]-HK). To further explore the diversity of oligomerization states and regulation within this family, we biophysically and biochemically characterized multiple EL346 homologs and found a range of HK oligomeric states and functions. Three LOV-HK homologs are primarily dimeric with differing structural and functional responses to light, while two Per-ARNT-Sim-HKs interconvert between differentially active monomers and dimers, suggesting dimerization might control enzymatic activity for these proteins. Finally, we examined putative interfaces in a dimeric LOV-HK, finding that multiple regions contribute to dimerization. Our findings suggest the potential for novel regulatory modes and oligomeric states beyond those traditionally defined for this important family of environmental sensors.

What are Headache Smartphone Application (App) Users Actually Looking for in Apps: A Qualitative Analysis of App Reviews to Determine a Patient Centered Approach to Headache Smartphone Apps.

BACKGROUND: Many headache smartphone applications (apps) are commercially available. A Modified Delphi Study aimed to determine specialists' expectations of what a headache app should entail but consumer expectations of headache apps have not been evaluated extensively. OBJECTIVE: To evaluate publicly available reviews of headache apps to understand app features that motivate the consumers to use apps. METHODS: The Google Play and Apple App Stores were systematically searched for headache/migraine diary apps with 10+ consumer reviews. A maximum of 300 "Most Helpful" reviews for each app were extracted. Four coders coded reviews and resolved discrepancies. Themes and subthemes were created based on codes used 5+ times. RESULTS: About 15 apps met the study criteria (9 Android, 6 IOS). 945 reviews were coded. Four themes emerged: (1) App allows users to track headache characteristics, potential triggers, and treatments; (2) App usability; (3) Personalization and features to assess trends in data are key motivators for app use; (4) Ease with exportation and viewing data is critical. DISCUSSION: A user-centered design with the ability to (1) customize key features including headache characteristics, potential triggers, and treatments, (2) assess trends in data, and (3) view and export data would best optimize headache smartphone applications based on consumer preference.

Intracellular Protein Editing to Enable Incorporation of Non-Canonical Residues into Endogenous Proteins.

The ability to study proteins in a cellular context is crucial to our understanding of biology. Here, we report a new technology for "intracellular protein editing", drawing from intein- mediated protein splicing, genetic code expansion, and endogenous protein tagging. This protein editing approach enables us to rapidly and site specifically install residues and chemical handles into a protein of interest. We demonstrate the power of this protein editing platform to edit cellular proteins, inserting epitope peptides, protein-specific sequences, and non-canonical amino acids (ncAAs). Importantly, we employ an endogenous tagging approach to apply our protein editing technology to endogenous proteins with minimal perturbation. We anticipate that the protein editing technology presented here will be applied to a diverse set of problems, enabling novel experiments in live mammalian cells and therefore provide unique biological insights.