GTP-Binding Proteins and Their Regulatory Actions on Ion Channels

Abstract

The science of ‘signal transduction mechanisms’ is the most dramatically progressing field in cell biology during the past several years. Guanine nucleotide- binding proteins (G-proteins) have been identified in almost all cells in every tissue, and their major roles are known to transduce various intracellular signals by interacting between receptor molecules and effector enzymes or ion channels. They regulate synaptic transmission, contractions of cardiac and smooth muscles, secretions of endocrine and exocrine cells, translation system of the messenger RNA, and mitotic cell cycles [17, 21, 58, 61].
This paper describes basic structures and functions of G-proteins and focuses on their modulatory or regulatory actions for ionic channels in the plasma membrane while attempting to put forward some possible unifying concept from the diverse information that has accumulated.