6k42

Structural highlights

Function

[GBG2_HUMAN] Guanine nucleotide-binding proteins (G proteins) are involved as a modulator or transducer in various transmembrane signaling systems. The beta and gamma chains are required for the GTPase activity, for replacement of GDP by GTP, and for G protein-effector interaction (By similarity). [GBB1_MOUSE] Guanine nucleotide-binding proteins (G proteins) are involved as a modulator or transducer in various transmembrane signaling systems. The beta and gamma chains are required for the GTPase activity, for replacement of GDP by GTP, and for G protein-effector interaction (By similarity). [GNAI1_BOVIN] Guanine nucleotide-binding proteins (G proteins) function as transducers downstream of G protein-coupled receptors (GPCRs) in numerous signaling cascades. The alpha chain contains the guanine nucleotide binding site and alternates between an active, GTP-bound state and an inactive, GDP-bound state. Signaling by an activated GPCR promotes GDP release and GTP binding. The alpha subunit has a low GTPase activity that converts bound GTP to GDP, thereby terminating the signal. Both GDP release and GTP hydrolysis are modulated by numerous regulatory proteins (By similarity). Signaling is mediated via effector proteins, such as adenylate cyclase. Inhibits adenylate cyclase activity, leading to decreased intracellular cAMP levels (By similarity). The inactive GDP-bound form prevents the association of RGS14 with centrosomes and is required for the translocation of RGS14 from the cytoplasm to the plasma membrane. Required for normal cytokinesis during mitosis (By similarity). Required for cortical dynein-dynactin complex recruitment during metaphase (By similarity).[UniProtKB:P10824][UniProtKB:P63096] [ADA2A_HUMAN] Alpha-2 adrenergic receptors mediate the catecholamine-induced inhibition of adenylate cyclase through the action of G proteins. The rank order of potency for agonists of this receptor is oxymetazoline > clonidine > epinephrine > norepinephrine > phenylephrine > dopamine > p-synephrine > p-tyramine > serotonin = p-octopamine. For antagonists, the rank order is yohimbine > phentolamine = mianserine > chlorpromazine = spiperone = prazosin > propanolol > alprenolol = pindolol.^[1]

References

1. ↑ Li C, Fan Y, Lan TH, Lambert NA, Wu G. Rab26 modulates the cell surface transport of alpha2-adrenergic receptors from the Golgi. J Biol Chem. 2012 Dec 14;287(51):42784-94. doi: 10.1074/jbc.M112.410936. Epub, 2012 Oct 26. PMID:23105096 doi:http://dx.doi.org/10.1074/jbc.M112.410936
2. ↑ Yuan D, Liu Z, Kaindl J, Maeda S, Zhao J, Sun X, Xu J, Gmeiner P, Wang HW, Kobilka BK. Activation of the alpha2B adrenoceptor by the sedative sympatholytic dexmedetomidine. Nat Chem Biol. 2020 Mar 9. pii: 10.1038/s41589-020-0492-2. doi:, 10.1038/s41589-020-0492-2. PMID:32152538 doi:http://dx.doi.org/10.1038/s41589-020-0492-2