1. Molecular Basis of Regulation of Ionic Channels by G Proteins
- Author
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Wadi N. Suki, Zhimin Zhou, Rolf Graf, Heidi E. Hamm, Koji Okabe, Jack Sanford, Ravi Iyengar, Juan Olate, Ching-Fong Liao, Atsuko Yatani, Axel P. N. Themmen, Juan Codina, Rafael Mattera, Arthur M. Brown, Mariel Birnbaumer, Yutaka Imoto, Lutz Birnbaumer, and Joel Abramowitz
- Subjects
G protein-coupled receptor kinase ,G beta-gamma complex ,GTP-binding protein regulators ,GTPase-activating protein ,Biochemistry ,G protein ,Heterotrimeric G protein ,Biology ,G protein-coupled receptor ,G alpha subunit - Abstract
Publisher Summary This chapter presents primary structure of G proteins as deduced from purified proteins and cloned subunits. It also discusses their functions and presents data on direct regulation of ionic channels by G proteins. Experiments on expression of subunits, either in bacteria or by in vitro translation of messenger RNA (mRNA) synthesized from complimentary DNA (cDNA), are discussed as tools for definitive assignment of function to a given G protein. The chapter also discusses the dynamics of G protein-mediated signal transduction. The key points discussed in the chapter include the existence of two superimposed regulatory cycles in which G proteins dissociate into α plus βγ upon activation by guanosine triphosphate (GTP) and where the dissociated α subunits hydrolyze GTP. The chapter emphasizes the action of receptors to catalyze rather than regulate by allostery the activation of G proteins by GTP and also the role of subunit dissociation, without which receptors cannot act as catalysts. It also provides an overview on intramembrane networking of G protein-mediated receptor-effector coupling.
- Published
- 1989
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