Guanine nucleotide binding proteins are heterotrimeric signal-transducing molecules comprising alpha， beta， and gamma subunits. GNAI1 represents the alpha subunit of an inhibitory complex. Guanine nucleotide-binding protein G（i） subunit alpha （GNAI1） functions to transmit information from cell surface receptors to intracellular effectors. GNAI1 binds guanine nucleotide， can hydrolyze GTP， and can interact with other proteins. GNAI1 is part of a complex that responds to beta-adrenergic signals by inhibiting adenylate cyclase. In addition， GNAI1 functions to open atrial potassium channels.
