A Non-immunogenic Bivalent d-Protein Potently Inhibits Retinal Vascularization and Tumor Growth.

We report a general approach to engineering multivalent d-proteins with antibody-like activities . Mirror-image phage display and structure-guided design were utilized to create a d-protein that uses receptor mimicry to antagonize vascular endothelial growth factor A (VEGF-A). Selections against the d-protein form of VEGF-A using phage-displayed libraries of two different domain scaffolds yielded two proteins that bound distinct receptor interaction sites on VEGF-A.

Methylthioninium chloride (methylene blue) induces autophagy and attenuates tauopathy in vitro and in vivo.

More than 30 neurodegenerative diseases including Alzheimer disease (AD), frontotemporal lobe dementia (FTD), and some forms of Parkinson disease (PD) are characterized by the accumulation of an aggregated form of the microtubule-binding protein tau in neurites and as intracellular lesions called neurofibrillary tangles. Diseases with abnormal tau as part of the pathology are collectively known as the tauopathies. Methylthioninium chloride, also known as methylene blue (MB), has been shown to reduce tau levels in vitro and in vivo and several different mechanisms of action have been proposed.

Synthesis of orthogonally reactive FK506 derivatives via olefin cross metathesis.

Chemical inducers of dimerization (CIDs) are employed in a wide range of biological applications to control protein localization, modulate protein-protein interactions and improve drug lifetimes. These bifunctional chemical probes are assembled from two synthetic modules, which each provide affinity for a distinct protein target. FK506 and its derivatives are often employed as modules in the syntheses of these bifunctional constructs, owing to the abundance and favorable distribution of their target, FK506-binding protein (FKBP).

FK506-binding protein (FKBP) partitions a modified HIV protease inhibitor into blood cells and prolongs its lifetime in vivo.

HIV protease inhibitors are a key component of anti-retroviral therapy, but their susceptibility to cytochrome P(450) metabolism reduces their systemic availability and necessitates repetitive dosing. Importantly, failure to maintain adequate inhibitor levels is believed to provide an opportunity for resistance to emerge; thus, new strategies to prolong the lifetime of these drugs are needed. Toward this goal, numerous prodrug approaches have been developed, but these methods involve creating inactive precursors that require enzymatic processing.

Bifunctional molecules evade cytochrome P(450) metabolism by forming protective complexes with FK506-binding protein.

Despite their large size and complexity, the macrolide natural products rapamycin and FK506 have excellent pharmacological characteristics. We hypothesize that these unexpected properties may arise from protective, high affinity interactions with the cellular FK506-binding protein, FKBP. In this model, the drug-FKBP complex might sequester the small molecule and limit its degradation by restricting access to metabolic enzymes.

Chemical control over protein-protein interactions: beyond inhibitors.

Protein-protein interactions have become attractive drug targets and recent studies suggest that these interfaces may be amenable to inhibition by small molecules. However, blocking specific interactions may not be the only way of manipulating the extensive network of interacting proteins. Recently, several approaches have emerged for promoting these interactions rather than inhibiting them.

The D1 dopamine receptor is constitutively phosphorylated by G protein-coupled receptor kinase 4.

G protein-coupled receptor (GPCR) kinases (GRKs) phosphorylate agonist-activated GPCRs, initiating their homologous desensitization. In this article, we present data showing that GRK4 constitutively phosphorylates the D1 receptor in the absence of agonist activation. This constitutive phosphorylation is mediated exclusively by the alpha isoform of GRK4; the beta, gamma, and delta isoforms are ineffective in this regard.

The role of phosphorylation in D1 dopamine receptor desensitization: evidence for a novel mechanism of arrestin association.

Homologous desensitization of D(1) dopamine receptors is thought to occur through their phosphorylation leading to arrestin association which interdicts G protein coupling. In order to identify the relevant domains of receptor phosphorylation, and to determine how this leads to arrestin association, we created a series of mutated D(1) receptor constructs. In one mutant, all of the serine/threonine residues within the 3rd cytoplasmic domain were altered (3rdTOT).