A5047205461- Receptor Mechanisms and Signaling
- Advanced Fluorescence Microscopy Techniques
- Photoreceptor and optogenetics research
- Neuropeptides and Animal Physiology
- Neuroscience and Neuropharmacology Research
- Pharmacological Effects and Assays
- Neurotransmitter Receptor Influence on Behavior
- Computational Drug Discovery Methods
- RNA and protein synthesis mechanisms
- Protein purification and stability
- Luminescence and Fluorescent Materials
- Enzyme Structure and Function
- Photosynthetic Processes and Mechanisms
- Chemical synthesis and alkaloids
- Traditional and Medicinal Uses of Annonaceae
- Alkaloids: synthesis and pharmacology
- Photochromic and Fluorescence Chemistry
- Diabetes Treatment and Management
- Lipid Membrane Structure and Behavior
- Metabolism, Diabetes, and Cancer
- Enzyme Catalysis and Immobilization
- Protein Kinase Regulation and GTPase Signaling
- Enzyme-mediated dye degradation
- bioluminescence and chemiluminescence research
- Neurobiology and Insect Physiology Research
Columbia University
2014-2024
New York Psychoanalytic Society and Institute
2017-2024
New York State Psychiatric Institute
2017-2024
Columbia University Irving Medical Center
2024
Royal College of Physicians
2016
Columbia College
2016
University of Rochester
2010-2016
Eastern Kentucky University
2005-2007
University of Kentucky
2007
β-arrestins bind G protein-coupled receptors to terminate protein signaling and facilitate other downstream pathways. Using single-molecule fluorescence resonance energy transfer imaging, we show that β-arrestin is strongly autoinhibited in its basal state. Its engagement with a phosphopeptide mimicking phosphorylated receptor tail efficiently releases the from N domain assume distinct conformations. Unexpectedly, find binding receptor, phosphorylation barcode identical isolated...
Bright, long-lasting organic fluorophores enable a broad range of imaging applications. "Self-healing" fluorophores, in which intra-molecularly linked protective agents quench photo-induced reactive species, exhibit both enhanced photostability and biological compatibility. However, the self-healing strategy has yet to achieve its predicted potential, particularly presence ambient oxygen where live-cell studies must often be performed. To identify key bottlenecks this technology that can...
Bright, photostable, and nontoxic fluorescent contrast agents are critical for biological imaging. "Self-healing" dyes, in which triplet states intramolecularly quenched, enable fluorescence imaging by increasing fluorophore brightness longevity, while simultaneously reducing the generation of reactive oxygen species that promote phototoxicity. Here, we systematically examine self-healing mechanism cyanine-class organic fluorophores spanning visible spectrum. We show Baird aromatic...
Mitragynine and 7-hydroxymitragynine (7OH) are the major alkaloids mediating biological actions of psychoactive plant kratom. To investigate structure–activity relationships mitragynine/7OH templates, we diversified aromatic ring indole at C9, C10, C12 positions investigated their G-protein arrestin signaling mediated by mu opioid receptors (MOR). Three synthesized lead C9 analogs replacing 9-OCH3 group with phenyl (4), methyl (5), or 3′-furanyl [6 (SC13)] substituents demonstrated partial...
The serotonergic transmitter system plays fundamental roles in the nervous neurotransmission, synaptic plasticity, pathological processes, and therapeutic effects of antidepressants psychedelics, as well gastrointestinal circulatory systems. We introduce a novel small molecule fluorescent agent, termed SERTlight, that specifically labels neuronal cell bodies, dendrites, axonal projections serotonin transporter (SERT) substrate. SERTlight was developed by an iterative molecular design...
Glutamate acts at eight metabotropic glutamate (mGlu) receptor subtypes expressed in a partially overlapping fashion distinct brain circuits. Recent evidence indicates that specific mGlu protomers can heterodimerize and these heterodimers exhibit different pharmacology when compared to their homodimeric counterparts. Group III agonist-induced suppression of evoked excitatory potentials induction long-term potentiation Schaffer collateral-CA1 (SC-CA1) synapses the rodent hippocampus be...
Free fatty acid receptor 1 (FFAR1) is highly expressed in enteroendocrine cells of the small intestine and pancreatic beta islet, where FFAR1 agonists function as GLP-1 insulin secretagogues, respectively. Most efficacious are so-called second-generation synthetic such AM5262, which, contrast to endogenous long-chain acids able signal through both IP3/Ca2+ cAMP pathways. Whereas IP3 signaling be expected for mainly Gq-coupled FFAR1, mechanism behind FFAR1-induced accumulation remains...
G protein-coupled receptors (GPCRs) signal through activation of proteins and subsequent modulation downstream effectors. More recently, signaling mediated by β-arrestin has also been implicated in important physiological functions. This led to great interest the identification biased ligands that favor either protein or β-arrestin-signaling pathways. However, nearly all screening techniques for measuring recruitment have required C-terminal receptor modifications can principle alter...
We report a novel affinity-based purification method for proteins expressed in Escherichia coli that uses the coordination of heme tag to an L-histidine-immobilized sepharose (HIS) resin. This approach provides affinity visible eye, facilitating tracking protein. show azurin and maltose binding protein are readily purified from cell lysate using HIS Mild conditions used; heme-tagged bound resin phosphate buffer, pH 7.0, eluted by adding 200-500 mM imidazole or buffer at 5 8. The exhibits low...
It is shown that cytochrome c heme lyase (CCHL) attaches covalently to peptides composed of the N-terminal segment cyt fused a non-heme containing protein, lending insight into substrate specificity CCHL and providing new route artificial proteins.
Heme peptides and their derivatives, also called microperoxidases (MPs), are employed as heme protein active site models, catalysts, charge-transfer chromophores. In this work, two approaches to the biosynthesis of novel MPs described. one method, expressed C-terminal tags azurin MP is liberated by proteolytic cleavage an endopeptidase. alternative approach, N-terminal cysteine protease domain (CPD) Vibrio cholerae MARTX toxin. Once activated inositol hexakisphosphate, CPD undergoes...
Conformational dynamics of proteins are important for function. However, obtaining information about specific conformations is difficult samples displaying heterogeneity. Here, time-resolved fluorescence resonance energy transfer used to characterize the folding single cytochrome c molecules. In particular, measurements lifetimes individual molecules labeled with a dye that quenched by heme were monitor conformational transitions protein under partially denaturing conditions. These studies...
In this study, we have developed a two receptor model system to describe the R and R* states of G-protein coupled receptors, specifically alpha1D adrenergic receptor. The models interact with agonist (epinephrine) antagonist (BMY7378) differently. active has increased interactions epinephrine. inactive BMY7378. We also explored protonation state ligands. When most basic amine was protonated, found hydrogen bonding aromatic interactions. Protonated epinephrine bonds Asp176 residues Trp172,...
Single-molecule FRET (smFRET) is a powerful imaging platform capable of revealing dynamic changes in the conformation and proximity biological molecules. The expansion smFRET into living cells creates both numerous new research opportunities challenges. Automating dataset curation processes critical to providing consistent, repeatable analysis an efficient manner, freeing experimentalists advance technical boundaries throughput what possible cells. Here, we devise automated solution problem...
In this study, we have developed a two model system to mimic the active and inactive states of G-protein coupled receptor specifically α1A adrenergic receptor. We docked agonists, epinephrine (phenylamine type) oxymetazoline (imidazoline type), as well antagonists, prazosin 5-methylurapidil, into models, inactive. The best docking complexes for both agonists had hydrophilic interactions with D106, while neither antagonist did. Prazosin hydrophobic F308 F312. predict from our study that state...
Opioid receptors belong to the superfamily of G protein coupled and are primarily responsive opiates produce analgesia, but also a variety side effects. One goal computational chemistry is determine interactions between ligand protein. This knowledge could allow for development opioid agonists without current Homology models human mu, kappa, delta were developed based on previously validated homology model endothelial differentiation gene. Docking native ligand, morphine, was performed. The...