Research articles

Polo-like kinase 1 (Plk1) regulates multiple processes that are important for cell proliferation, and it is a promising anticancer drug target. Efforts to inhibit Plk1 function by disrupting interactions that are essential for its proper localization identify a high-affinity alkylated phosphopeptide ligand specific for Plk1.

Overabundance of the eIF2–GTP–Met-tRNAi translational initiation complex has been linked to malignant transformation. N,N'-diarylurea chemical probes that block ternary complex assembly through heme-regulated inhibitor kinase activation validate translational initiation pathways as a potential anti-cancer targets.

Protein lysine methyltransferases modulate the activities of chromatin and non-chromatin proteins by specific methylation of lysine side chains. A large-scale structure-based design approach has yielded a new chemical probe that potently and selectively inhibits G9a and GLP methyltransferases in cells.

The synthetic compound Shield-1 can already be used to protect designed fusion proteins from degradation. The development of a new protein domain that is degraded upon addition of Shield-1 expands the compound's utility in controlling protein function and allows the simultaneous degradation and stabilization of different constructs.

A search through hydrophobic chemical space identifies an adamantane tag that targets dehalogenase fusion proteins for degradation, as demonstrated for both cytosolic and transmembrane proteins; and in zebrafish and mice. This molecule provides a new tool to study protein function with precise control.

Plutonium (Pu), a radiotoxic element, enters cells via an unknown mechanism. Solution structures and X-ray imaging studies reveal that Pu binds transferrin, and the complex can be taken up by cells via receptor-mediated endocytosis only if iron is contained in transferrin's N-lobe.

Protein-focused lead-identification strategies may be limited in their ability to identify small molecules that bind to cellular RNAs. Docking small molecules against the structural ensemble substantially improves the docking accuracy of TAR and has led to the identification of six new TAR binders, one of which inhibits HIV-1 replication.

Compounds identified from a high-content screen implicate RTK activation as well as GSK-3 inhibition in regulating SMN levels and point to a therapeutic strategy for treating spinal muscular atrophy.

A quantitative sensor of spatial and temporal dynamics of activity of the protein tyrosine kinase Src shows that its activity peaks 1–2 μm from the leading edge of cells undergoing lamellipodial membrane extension, and the activation is correlated with protrusion velocity.

Investigations of reveromycin biosynthesis, including metabolite analysis, feeding experiments and in vitro tests of enzyme function, point to a two-step mechanism for formation of the central spiroacetal, in which RevG oxidizes a stable acyclic precursor and RevJ catalyzes the stereocontrolled cyclization.

FrsA is responsible for the metabolic switch between fermentation and respiration, but the basis for this function has been unknown. Biochemical, structural and in vivo analyses now demonstrate that FrsA is a cofactor-independent pyruvate decarboxylase and thus directly controls carbon flux.

Phosphorylation of the Huntington's disease protein Htt by CK2 leads to Htt nuclear translocation in response to stress. Inhibition of other kinase pathways can restore phosphorylation to hypophosphorylated Htt in Huntington's disease and may lead to a therapeutic strategy.

Two crystal structures of a three-domain class II diterpene cyclase with substrate and product analogs provide new insights into the mechanistic pathway of this enzyme and illuminate evolutionary and functional relationships within terpenoid biosynthesis more generally.

The design and implementation of a high-yielding enzymatic route to 1,4-butanediol—a compound not known to be produced naturally—provides a compelling example of how metabolic engineering can be harnessed for the microbial conversion of carbohydrate feedstocks to desired small molecules.

PUF proteins bind RNA sequences through specific interactions between PUF repeats and adenine, guanine and uracil bases. A directed evolution approach has identified new PUF repeats that specifically bind cytosine, which enables the recognition of diverse RNA sequences by engineered PUF proteins.

Investigations of serine hydrolases have been frustrated by a lack of selective chemical inhibitors. Profiling of synthetically accessible 1,2,3-triazole ureas in cells and mice now identifies several effective compounds, application of which yields new insights into N-acetylation by APEH.

Single-molecule fluorescence resonance energy transfer allows visualization of three distinct phases of DNA digestion mediated by λ exonuclease and identifies base melting as a rate-limiting step in the reaction pathway.

SAM riboswitches are RNA elements that regulate bacterial gene expression in response to binding of the small-molecule metabolite S-adenosylmethionine. Assembly of a functional SAM-I riboswitch occurs hierarchically and involves magnesium-induced preorganization of the SAM binding site.

SAM riboswitches are RNA elements that regulate bacterial gene expression in response to binding of the small-molecule metabolite, S-adenosylmethionine. The SAM-II riboswitch binds its ligand through a conformational capture mechanism that is dependent on formation of a transient pseudoknot.

D-Ornithine has been used as a supplement under the assumption that it increases production of pyrrolysine-containing proteins, but detailed characterization and investigations of pyrrolysine biosynthesis now demonstrate these modified proteins contain an entirely different amino acid.