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8.A.92.  The G-Protein αβγ Complex (GPC) Family 

G-proteins, including either the α-subunit (Galpha) or the βγ-subunit complex (Gbetagamma), regulate a variety of channels (TC class 1) and transport systems (carriers and primary active transporters ;TC classes 2 and 3, respectively). For example, ACh enhances calcium channel, Cav1.2b currents via muscarinic M2 receptors that couple sequentially to Gbetagamma, PI3K, a novel PKC, and c-Src (Callaghan et al. 2004), and the calcium channel, Cav2 is regulated by G-proteins (Currie 2010; Zamponi and Currie 2013). Also, The G protein-coupled inwardly rectifying K+ channel, GIRK1/GIRK4, can be activated by receptors coupled to the Galpha(i) subunit (Hill and Peralta 2001). Moreover, neuronal G protein-coupled inwardly-rectifying potassium channels (GIRKs, Kir3.x) can be activated or inhibited by distinct classes of receptors (Galphai/o and Galphaq/11-coupled, respectively), providing dynamic regulation of neuronal excitability. Lei et al. 2003 used a mammalian heterologous expression system to address mechanisms of GIRK channel regulation by Galpha and Gbetagamma subunits. Like beta1- and beta2-containing Gbetagamma dimers, GIRK channels are also activated by G protein betagamma dimers containing beta3 and beta4 subunits, but are inhibited by beta5-containing Gbetagamma dimers and/or by Galpha proteins of the Galphaq/11 family. The properties of Gbeta5-mediated inhibition suggest that beta5-containing Gbetagamma dimers act as competitive antagonists of other activating Gbetagamma pairs on GIRK channels (Lei et al. 2003). G-protein-coupled receptors control Ca2+ entry and Ca2+-dependent events such as neurotransmitter and hormone release (McDavid and Currie 2006). Finally, Gαi2 activates the TRPC4 channel by direct binding, which then induces Ca2+ entry (Myeong et al. 2015), and the G protein betagamma subunit complex modulates ionotropic glycine receptors, GlyRs (Yevenes et al. 2006).

Beta3 regulates the formation of transport carriers at the trans golgi nextwork (TGN), and fission of transport carriers at the TGN is dependent on PLCbeta3, which is necessary to activate PKCeta and PKD in that Golgi compartment, via DAG production (Díaz Añel 2007). 

Two Gbetagamma dimers of the Arabidopsis thaliana heterotrimeric G protein complex are differentially localized to the central and cortical tissues of the Arabidopsis roots. A null mutation in either the single beta (AGB1) or the two gamma (AGG1 and AGG2) subunits alters auxin transport (Zamponi and Currie 2013). Also, The G protein-coupled inwardly rectifying K+ channel, GIRK1/GIRK4, can be activated by receptors coupled to the Galpha(i) subunit (Hill and Peralta 2001). Moreover, neuronal G protein-coupled inwardly-rectifying potassium channels (GIRKs, Kir3.x) can be activated or inhibited by distinct classes of receptors (Galphai/o and Galphaq/11-coupled, respectively), providing dynamic regulation of neuronal excitability. Lei et al. 2003 used a mammalian heterologous expression system to address mechanisms of GIRK channel regulation by Galpha and Gbetagamma subunits. Like beta1- and beta2-containing Gbetagamma dimers, GIRK channels are also activated by G protein betagamma dimers containing beta3 and beta4 subunits, but are inhibited by beta5-containing Gbetagamma dimers and/or by Galpha proteins of the Galphaq/11 family. The properties of Gbeta5-mediated inhibition suggest that beta5-containing Gbetagamma dimers act as competitive antagonists of other activating Gbetagamma pairs on GIRK channels (Lei et al. 2003). G-protein-coupled receptors control Ca2+ entry and Ca2+-dependent events such as neurotransmitter and hormone release (McDavid and Currie 2006). Finally, Gαi2 activates the TRPC4 channel by direct binding, which then induces Ca2+ entry (Myeong et al. 2015), and the G protein betagamma subunit complex modulates ionotropic glycine receptors, GlyRs (Yevenes et al. 2006).

Beta3 regulates the formation of transport carriers at the trans golgi nextwork (TGN), and fission of transport carriers at the TGN is dependent on PLCbeta3, which is necessary to activate PKCeta and PKD in that Golgi compartment, via DAG production (Díaz Añel 2007). 

Two Gbetagamma dimers of the Arabidopsis thaliana heterotrimeric G protein complex are differentially localized to the central and cortical tissues of the Arabidopsis roots. A null mutation in either the single beta (AGB1) or the two gamma (AGG1 and AGG2) subunits alters auxin transport (Mudgil et al. 2009).

References associated with 8.A.92 family:

Callaghan, B., S.D. Koh, and K.D. Keef. (2004). Muscarinic M2 receptor stimulation of Cav1.2b requires phosphatidylinositol 3-kinase, protein kinase C, and c-Src. Circ Res 94: 626-633. 14739158
Currie, K.P. (2010). G protein modulation of CaV2 voltage-gated calcium channels. Channels (Austin) 4: 497-509. 21150298
Díaz Añel, A.M. (2007). Phospholipase C beta3 is a key component in the Gbetagamma/PKCeta/PKD-mediated regulation of trans-Golgi network to plasma membrane transport. Biochem. J. 406: 157-165. 17492941
Hill, J.J. and E.G. Peralta. (2001). Inhibition of a Gi-activated potassium channel (GIRK1/4) by the Gq-coupled m1 muscarinic acetylcholine receptor. J. Biol. Chem. 276: 5505-5510. 11060307
Lei, Q., M.B. Jones, E.M. Talley, J.C. Garrison, and D.A. Bayliss. (2003). Molecular mechanisms mediating inhibition of G protein-coupled inwardly-rectifying K+ channels. Mol. Cells 15: 1-9. 12661754
McDavid, S. and K.P. Currie. (2006). G-proteins modulate cumulative inactivation of N-type (Cav2.2) calcium channels. J. Neurosci. 26: 13373-13383. 17182788
Mudgil, Y., J.F. Uhrig, J. Zhou, B. Temple, K. Jiang, and A.M. Jones. (2009). Arabidopsis N-MYC DOWNREGULATED-LIKE1, a positive regulator of auxin transport in a G protein-mediated pathway. Plant Cell 21: 3591-3609. 19948787
Myeong, J., M. Kwak, J.P. Jeon, C. Hong, J.H. Jeon, and I. So. (2015). Close spatio-association of the transient receptor potential canonical 4 (TRPC4) channel with Gαi in TRPC4 activation process. Am. J. Physiol. Cell Physiol. 308: C879-889. 25788576
Yevenes, G.E., G. Moraga-Cid, L. Guzmán, S. Haeger, L. Oliveira, J. Olate, G. Schmalzing, and L.G. Aguayo. (2006). Molecular determinants for G protein betagamma modulation of ionotropic glycine receptors. J. Biol. Chem. 281: 39300-39307. 17040914
Zamponi, G.W. and K.P. Currie. (2013). Regulation of Ca(V)2 calcium channels by G protein coupled receptors. Biochim. Biophys. Acta. 1828: 1629-1643. 23063655