Description
GNG13 is a subunit of heterotrimeric G proteins which consist of alpha, beta, and gamma subunits. Heterotrimeric G proteins are membrane-bound GTPases that are linked to 7-TM receptors. They function as signal transducers for the 7-transmembrane-helix G protein-coupled receptors. They are involved as a modulator or transducer in various transmembrane signaling systems. Each G protein is composed of an alpha-, beta- and gamma-subunit and is bound to GDP in the 'off' state. Ligand-receptor binding results in detachment of the G protein, switching it to an 'on' state and permitting Galpha activation of second messenger signaling cascades. There are several types of Galpha proteins; besides, some Gbetagamma subunits have active functions. Gbetagamma coupled to H1 receptors can activate PLA2 and Gbetagamma coupled to M1 receptors can activate KIR channels. The beta and gamma chains are required for the GTPase activity, for replacement of GDP by GTP, and G protein-effector interaction. GNG13 is a gamma subunit that is expressed in taste, retinal, and neuronal tissues and plays a key role in taste transduction