Publications in VIVO
 

Griffin, Patrick Faculty Member

Positions

Dr. Patrick Griffin focuses on the application of mass spectrometry technology to probe protein-ligand and protein-protein interactions.

Affiliation

Publications

selected publications

Research

research overview

  • Structural and Chemical Biology of Enzymes and Receptors

    Our group combines chemical and cell biology with structural biology to study mechanism and structure-function of enzymes and receptors; particularly kinases, G-protein coupled receptors (GPCRs) and nuclear receptors (NRs). During the past few years we have focused on developing hydrogen/deuterium exchange (HDX) technology for probing the mechanism of activation of intact nuclear receptor complexes. Specifically we have used HDX, chemical libraries and cell-based assays to better understand ligand activation and co-receptor/co-factor interaction within the vitamin D receptor (VDR) and the peroxisome proliferator-activated receptor (PPAR) complex. We have applied HDX and chemical approaches to the study of the orphan nuclear receptors LRH-1 and RORA (in collaboration with Thomas Burris) which have been implicated in cancer and metabolic disorders. Our HDX platform is part of the center based initiative of the Scripps Research Institute Molecular Screening Center (SRIMSC) and is being applied to several chemical probe development projects. Also as part of the SRIMSC initiative and in collaboration with Juliana Conkright, we have developed novel screening platforms to facilitate the discovery of potent and selective nuclear receptor modulators. Finally, to broaden the application of HDX we have initiated collaborations with the Rosen and Stevens’ laboratories, TSRI CA, to study the dynamics of GPCRs upon ligand interaction.

    Mechanistic Studies of Ligand Activation of VDR/RXR Full Length Heterodimer Complex

    Here we are applying HDX towards the characterization of ligand activation of the vitamin D receptor (VDR) in complex with its co-receptor retinoid X receptor alpha (RXRa). This project is driving further development of our HDX platform to facilitate the analysis of large transcriptional complexes. We have successfully probed the dynamics of the functional domains of both VDR and RXR within this complex as a function of both ligand and DNA interaction. Our data clearly demonstrates the role of DNA interaction in the functional state of the VDR/RXR heterodimer complex by directly controlling dynamics of surfaces of the receptor complex that interact with co-activators.

    Probing GPCRs by HDX

    GPCRs are an important family of trans-membrane signaling proteins and are therapeutic targets in many disorders. The characterization of the structure and dynamics of these receptors present a considerable analytical challenge due to the hydrophobic nature of their transmembrane domains. The Stevens’ lab recently solved the structure of the beta-2 adrenergic receptor at 2.4 Å resolution and in collaboration with their lab we have initiated studies to probe beta-2 adrenergic receptor-ligand interactions.

    Structural and Chemical Biology of the Orphan Nuclear Receptor LRH-1

    Our laboratory has taken a multi-pronged approach to understanding the biology of the orphan nuclear receptor LRH-1 (liver receptor homolog-1). Modulation of LRH-1 activity has been implicated in breast cancer, cholesterol homeostasis, and in intestinal inflammation. We have developed several HTS ready assays to facilitate screening for small molecules that positively modulate (agonize) or negatively modulate (inverse agonize) the activity of the receptor. More importantly, we have developed several functional assays to better understand the potential utility of small molecule modulators of LRH-1 for treatment of breast cancer and metabolic disorders.

    Novel Modulators of ROR(alpha)

    Using a unique human nuclear receptor library we have discovered novel modulators of ROR(alpha). In collaboration with William Roush and the SRIMSC, we have generated structure-activity-relationships around this molecule in an effort to improve potency and selectivity. HDX is being employed to guide SAR studies in this project. In addition, we have developed several cell-based assays to examine the effects of these molecules in biological pathways controlled by RORα; such as the control of adipogenesis and it role in insulin sensitization.

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