G proteins

(redirected from guanine nucleotide-binding protein)

G pro·teins

intracellular membrane-associated proteins activated by several (for example, β-adrenergic) receptors; they serve as second messengers or transducers of the receptor-initiated response to intracellular elements such as enzymes to initiate an effect. These proteins have a high affinity for guanine nucleotides and hence are named G proteins.

G proteins

Cell messengers that relay signals from over 1000 different cell membrane receptors to many different intracellular effectors such as enzymes and ion channels. G proteins have three subunits, alpha, beta, and gamma, each coded for by a different gene, selected from a total of 34 genes. G protein function is switched on and off by the binding and hydrolysis of guanosine triphosphate to the alpha subunit which is loosely attached to the others. Binding causes the beta and gamma fragments to separate as a dimer and to activate downstream effectors.
References in periodicals archive ?
In APC, volatile anaesthetics appear to mediate their protection in cardiomyocytes by selectively priming sarcolemmal and mitochondrial adenosine-triphosphate-sensitive potassium channels through triggering a complex signal cascade involving protein kinase C, protein tyrosine kinase, second messenger signal systems such as guanine nucleotide-binding proteins and by the influence on [Ca.
activities, such as the citric acid cycle and the activation of guanine nucleotide-binding proteins (G-proteins), which typically switch between
GPCRs transmit extracellular signals by binding coupled guanine nucleotide-binding proteins, or G proteins, in the cytoplasm.
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