2011.02.16

Session 1
Chair: Juro Sakai and Takao Hamakubo

10:00 – 10:10
Opening remark

Takao Shimizu
Dean, Faculty of Medicine
Professor, Department of Biochemistry and Molecular Biology
The University of Tokyo



10:10 – 10:30
Introduction of Molecular Dynamics and Antibody Drug Design project

Takao Hamakubo
Professor, Laboratory of Systems Biology and Medicine
Research Center for Advanced Science and Technology
The University of Tokyo



10:30 – 11:10
Antibody-mediated crystallization of membrane proteins

So Iwata
Professor, Department of Cell Biology
Faculty of Medicine, University of Kyoto

11:10 - 11:50
Genome-wide approaches to understanding nuclear receptor function

Christopher Glass
Professor of Medicine and Cellular and Molecular Medicine
School of Medicine, University of California, San Diego

Abstract
Nuclear receptors comprise a family of ligand-dependent transcription factors that regulate diverse aspects of reproduction, development, homeostasis and immunity. We have utilized the macrophage, a cell that plays essential roles in immunity and tissue homeostasis, as a model system for exploring the molecular mechanisms by which nuclear hormone receptors positively and negatively regulate gene expression in response to natural and synthetic ligands. Our recent genome-wide studies have led to a model in which nuclear receptors act in a cell-restricted manner as a consequence of the actions of a small set of pioneering, lineage-determining factors, that establish most of the enhancer-like regions within the cell. These ‘protoenhancers’ that can subsequently be acted upon by a diverse set of signal-dependent transcription factors. In the macrophage, key lineage determining factors include PU.1, C/EBPα/β and AP-1 proteins. These transcription factors function in a collaborative manner to bind to macrophage-specific enhancer regions, initiate nucleosome remodeling and histone modifications, and establish ‘open’ regions of chromatin. These regions can then be acted upon by nuclear receptors to positively or negatively regulate vicinal genes.

Session 2
Chair: Tohru Kozasa and Hideaki Fujitani

13:20 – 14:00
G proteins as Selective Conformational Filters on GPCRs.

Roger Sunahara
Department of Pharmacology, University of Michigan Medical School

Abstract
G protein-coupled receptors (GPCRs) arguably remain the largest family of targets for therapeutics on the market today. However the molecular mechanism by which many of these ligands exert their therapeutic effect is not clear. Here we study the influence of agonists, inverse agonists and neutral antagonists on receptor conformation and determine how their binding may be modulated by G proteins. We utilize nanometer-scale phospholipid-containing particles, reconstituted High Density Lipoprotein (rHDL), as a platform to reconstitute purified preparations of the 2-adrenergic receptor. We take advantage of the contributions of phospholipids toward GPCR stability and G protein coupling in this integrated, homogeneous and monodispersed reconstitution approach. Moreover equal access to both sides of the bilayer, a property that plagues reconstituted vesicle preparations, allows efficient protein•receptor and ligand•receptor interactions. Here we provide pharmacological and biophysical evidence to suggest that G proteins exert a strong allosteric influence on ligand-directed receptor conformations. Of particular interest is the surprising modulatory role that G proteins apply to neutral antagonist binding, a characteristic that challenges their intrinsically “neutral” designation.

14:10 – 14:50
General regulation of phospholipase C isozymes

John Sondek
Professor of Pharmacology, UNC at Chapel Hill Professor of Biochemistry and Biophysics, UNC at Chapel Hill

Abstract
Phospholipase C isozymes control numerous signaling cascades through the regulated hydrolysis of the phosphoinositide, PIP2. The set of thirteen PLCs in humans are activated by numerous and disparate inputs, including: elevated calcium, heterotrimeric G proteins, Ras-related GTPases, and tyrosine kinases. Despite the diverse array of inputs that activate auto-inhibited PLCs, general mechanisms govern both the auto-inhibition and activation of PLCs. This talk will introduce these unifying concepts and discuss in detail: i) the reciprocal regulation of PLC-β isozymes by heterotrimeric G proteins of the Gq/11 family and ii) the activation of PLC-γ isozymes by phosphorylation mediated by receptor tyrosine kinases.

14:50 – 15:00
Concluding Remark

Tatsuhiko Kodama
Director of MDADD Program
Professor, Laboratory of Systems Biology and Medicine
Research Center for Advanced Science and Technology
The University of Tokyo