gtp binding protein alpha subunits


Summary: The GTPase-containing subunits of heterotrimeric GTP-binding proteins. When dissociated from the heterotrimeric complex these subunits interact with a variety of second messenger systems. Hydrolysis of GTP by the inherent GTPase activity of the subunit causes it to revert to its inactive (heterotrimeric) form. The GTP-Binding protein alpha subunits are grouped into families according to the type of action they have on second messenger systems.

Top Publications

  1. Zhang L, Hu G, Cheng Y, Huang J. Heterotrimeric G protein alpha and beta subunits antagonistically modulate stomatal density in Arabidopsis thaliana. Dev Biol. 2008;324:68-75 pubmed publisher
    ..Taken together, these results suggest that the stomatal density in Arabidopsis is modulated by GPA1 and AGB1 in an antagonistic manner. ..
  2. Zeilinger S, Reithner B, Scala V, Peissl I, Lorito M, Mach R. Signal transduction by Tga3, a novel G protein alpha subunit of Trichoderma atroviride. Appl Environ Microbiol. 2005;71:1591-7 pubmed
    ..Thus, T. atroviride Tga3 has a general role in vegetative growth and can alter mycoparasitism-related characteristics, such as infection structure formation and chitinase gene expression. ..
  3. Willard F, Siderovski D. Purification and in vitro functional analysis of the Arabidopsis thaliana regulator of G-protein signaling-1. Methods Enzymol. 2004;389:320-38 pubmed
    ..This article describes methods for the purification and in vitro functional analysis of the RGS box of AtRGS1. ..
  4. Reithner B, Brunner K, Schuhmacher R, Peissl I, Seidl V, Krska R, et al. The G protein alpha subunit Tga1 of Trichoderma atroviride is involved in chitinase formation and differential production of antifungal metabolites. Fungal Genet Biol. 2005;42:749-60 pubmed
    ..atroviride. ..
  5. Znoiko S, Rohrer B, Lu K, Lohr H, Crouch R, Ma J. Downregulation of cone-specific gene expression and degeneration of cone photoreceptors in the Rpe65-/- mouse at early ages. Invest Ophthalmol Vis Sci. 2005;46:1473-9 pubmed
    ..Early administration of 9- or 11-cis retinal can partially prevent cone loss, suggesting that the absence of 11-cis chromophore may be responsible for the early cone degeneration. ..
  6. Dignard D, Andre D, Whiteway M. Heterotrimeric G-protein subunit function in Candida albicans: both the alpha and beta subunits of the pheromone response G protein are required for mating. Eukaryot Cell. 2008;7:1591-9 pubmed publisher
  7. Hsueh Y, Xue C, Heitman J. G protein signaling governing cell fate decisions involves opposing Galpha subunits in Cryptococcus neoformans. Mol Biol Cell. 2007;18:3237-49 pubmed
    ..The incorporation of an additional Galpha into the regulatory circuit enabled increased signaling complexity and facilitated cell fate decisions involving choice between yeast growth and filamentous asexual/sexual development. ..
  8. Willard F, Zheng Z, Guo J, Digby G, Kimple A, Conley J, et al. A point mutation to Galphai selectively blocks GoLoco motif binding: direct evidence for Galpha.GoLoco complexes in mitotic spindle dynamics. J Biol Chem. 2008;283:36698-710 pubmed publisher
    ..GoLoco motif protein complexes in microtubule dynamics and spindle function during cell division as well as to delineate potential roles for GoLoco motifs in receptor-mediated signal transduction. ..
  9. Head B, Patel H, Roth D, Lai N, Niesman I, Farquhar M, et al. G-protein-coupled receptor signaling components localize in both sarcolemmal and intracellular caveolin-3-associated microdomains in adult cardiac myocytes. J Biol Chem. 2005;280:31036-44 pubmed

More Information


  1. Huang J, Taylor J, Chen J, Uhrig J, Schnell D, Nakagawa T, et al. The plastid protein THYLAKOID FORMATION1 and the plasma membrane G-protein GPA1 interact in a novel sugar-signaling mechanism in Arabidopsis. Plant Cell. 2006;18:1226-38 pubmed
    ..The interaction between THF1 and GPA1 has been confirmed by in vitro and in vivo coimmunoprecipitation, FRET analysis, and genetic epistasis and provides evidence of a sugar-signaling mechanism between plastids and the plasma membrane. ..
  2. Johnston C, Taylor J, Gao Y, Kimple A, Grigston J, Chen J, et al. GTPase acceleration as the rate-limiting step in Arabidopsis G protein-coupled sugar signaling. Proc Natl Acad Sci U S A. 2007;104:17317-22 pubmed
  3. Chang M, Chae K, Han D, Jahng K. The GanB Galpha-protein negatively regulates asexual sporulation and plays a positive role in conidial germination in Aspergillus nidulans. Genetics. 2004;167:1305-15 pubmed
    ..Taken together, these results indicated that GanB plays a positive role during germination, possibly through carbon source sensing, and negatively regulates asexual conidiation in A. nidulans. ..
  4. Anjard C, Su Y, Loomis W. Steroids initiate a signaling cascade that triggers rapid sporulation in Dictyostelium. Development. 2009;136:803-12 pubmed publisher
    ..SDF-3 is at the head of the cascade that amplifies the signal for encapsulation to ensure the rapid, synchronous formation of spores...
  5. Park D, Rose L. Dynamic localization of LIN-5 and GPR-1/2 to cortical force generation domains during spindle positioning. Dev Biol. 2008;315:42-54 pubmed publisher
  6. Gao Y, Zeng Q, Guo J, Cheng J, Ellis B, Chen J. Genetic characterization reveals no role for the reported ABA receptor, GCR2, in ABA control of seed germination and early seedling development in Arabidopsis. Plant J. 2007;52:1001-13 pubmed
    ..Taken together, our results do not support the notion that GCR2 is an ABA-signaling GPCR in seed germination and early seedling development. ..
  7. Rogers S, Wiedemann U, Hacker U, Turck C, Vale R. Drosophila RhoGEF2 associates with microtubule plus ends in an EB1-dependent manner. Curr Biol. 2004;14:1827-33 pubmed
  8. Brem R, Storey J, Whittle J, Kruglyak L. Genetic interactions between polymorphisms that affect gene expression in yeast. Nature. 2005;436:701-3 pubmed
    ..Our results indicate that genetic interactions are widespread in the genetics of transcript levels, and that many QTLs will be missed by single-locus tests but can be detected by two-stage tests that allow for interactions. ..
  9. Garzón J, Rodríguez Muñoz M, López Fando A, Sánchez Blázquez P. The RGSZ2 protein exists in a complex with mu-opioid receptors and regulates the desensitizing capacity of Gz proteins. Neuropsychopharmacology. 2005;30:1632-48 pubmed
    ..These results indicate that both RGSZ1 and RGSZ2 proteins influence mu receptor signaling by sequestering Galpha subunits, therefore behaving as effector antagonists. ..
  10. Kawasaki L, Saviñón Tejeda A, Ongay Larios L, Ramirez J, Coria R. The Gbeta(KlSte4p) subunit of the heterotrimeric G protein has a positive and essential role in the induction of mating in the yeast Kluyveromyces lactis. Yeast. 2005;22:947-56 pubmed
    ..cerevisiae but fails to restore the mating deficiency of Scste4Delta mutant. The data presented indicate that the mating pathway of K. lactis is positively and cooperatively regulated by both the Galpha and the Gbeta subunits. ..
  11. Peeters T, Louwet W, Geladé R, Nauwelaers D, Thevelein J, Versele M. Kelch-repeat proteins interacting with the Galpha protein Gpa2 bypass adenylate cyclase for direct regulation of protein kinase A in yeast. Proc Natl Acad Sci U S A. 2006;103:13034-9 pubmed
    ..Importantly, we show that Krh1/2 also enhance the association between mouse R and C subunits, suggesting that Krh control of PKA has been evolutionarily conserved. ..
  12. Slessareva J, Routt S, Temple B, Bankaitis V, Dohlman H. Activation of the phosphatidylinositol 3-kinase Vps34 by a G protein alpha subunit at the endosome. Cell. 2006;126:191-203 pubmed
    ..More remarkably, these proteins appear to comprise a preformed effector-G beta subunit assembly and function at the endosome rather than at the plasma membrane. ..
  13. Liu X, Yue Y, Li B, Nie Y, Li W, Wu W, et al. A G protein-coupled receptor is a plasma membrane receptor for the plant hormone abscisic acid. Science. 2007;315:1712-6 pubmed
    ..The binding of ABA to the receptor leads to the dissociation of the receptor-GPA1 complex in yeast. Our results demonstrate that this G protein-coupled receptor is a plasma membrane ABA receptor. ..
  14. Mao H, Zhao Q, Daigle M, Ghahremani M, Chidiac P, Albert P. RGS17/RGSZ2, a novel regulator of Gi/o, Gz, and Gq signaling. J Biol Chem. 2004;279:26314-22 pubmed
    ..Differences observed between in vitro GAP assays and whole-cell signaling suggest additional determinants of the G-protein specificity of RGS GAP effects that could include receptors and effectors. ..
  15. Assmann S. G proteins Go green: a plant G protein signaling FAQ sheet. Science. 2005;310:71-3 pubmed
    ..Pathways in Science's Signal Transduction Knowledge Environment Connections Maps database provide details about the emerging roles of G proteins in several cellular processes of plants. ..
  16. Bringmann H, Cowan C, Kong J, Hyman A. LET-99, GOA-1/GPA-16, and GPR-1/2 are required for aster-positioned cytokinesis. Curr Biol. 2007;17:185-91 pubmed
    ..We conclude that LET-99 and the G proteins define a molecular pathway required for aster-positioned cytokinesis. ..
  17. Joo J, Wang S, Chen J, Jones A, Fedoroff N. Different signaling and cell death roles of heterotrimeric G protein alpha and beta subunits in the Arabidopsis oxidative stress response to ozone. Plant Cell. 2005;17:957-70 pubmed
  18. Gookin T, Kim J, Assmann S. Whole proteome identification of plant candidate G-protein coupled receptors in Arabidopsis, rice, and poplar: computational prediction and in-vivo protein coupling. Genome Biol. 2008;9:R120 pubmed publisher
    ..Our computational and wet-bench results provide the first step toward understanding the diversity, conservation, and functional roles of plant candidate G-protein coupled receptors. ..
  19. Zhang W, He S, Assmann S. The plant innate immunity response in stomatal guard cells invokes G-protein-dependent ion channel regulation. Plant J. 2008;56:984-96 pubmed publisher
    ..These new findings provide insights into the largely elusive signaling process underlying PTI-associated guard cell responses. ..
  20. Birnbaumer L. Expansion of signal transduction by G proteins. The second 15 years or so: from 3 to 16 alpha subunits plus betagamma dimers. Biochim Biophys Acta. 2007;1768:772-93 pubmed
    ..Emphasis is placed in presenting how the field developed with the hope of conveying why many of the new findings were made. ..
  21. Cameron M, Pozdeyev N, Vugler A, Cooper H, Iuvone P, Lucas R. Light regulation of retinal dopamine that is independent of melanopsin phototransduction. Eur J Neurosci. 2009;29:761-7 pubmed publisher
    ..Our data suggest that light regulation of DA, a pivotal retinal neuromodulator, originates primarily with rods and cones, and that melanopsin is neither necessary nor sufficient for this photoresponse. ..
  22. Schmoll M. The information highways of a biotechnological workhorse--signal transduction in Hypocrea jecorina. BMC Genomics. 2008;9:430 pubmed publisher
    ..A better understanding of these signals as well as their transmission machinery can provide sources for improvement of biotechnological processes...
  23. Fan L, Zhang W, Chen J, Taylor J, Jones A, Assmann S. Abscisic acid regulation of guard-cell K+ and anion channels in Gbeta- and RGS-deficient Arabidopsis lines. Proc Natl Acad Sci U S A. 2008;105:8476-81 pubmed publisher
    ..Our studies highlight unique aspects of ion channel regulation by heterotrimeric G proteins and relate these aspects to stomatal aperture control, a key determinant of plant biomass acquisition and drought tolerance. ..
  24. Lafon A, Seo J, Han K, Yu J, d Enfert C. The heterotrimeric G-protein GanB(alpha)-SfaD(beta)-GpgA(gamma) is a carbon source sensor involved in early cAMP-dependent germination in Aspergillus nidulans. Genetics. 2005;171:71-80 pubmed
    ..Furthermore, GanB may function in sensing various carbon sources and subsequent activation of downstream signaling for germination. ..
  25. Pandey S, Assmann S. The Arabidopsis putative G protein-coupled receptor GCR1 interacts with the G protein alpha subunit GPA1 and regulates abscisic acid signaling. Plant Cell. 2004;16:1616-32 pubmed
    ..Because gpa1 mutants exhibit insensitivity in aspects of guard cell ABA and S1P responses, whereas gcr1 mutants exhibit hypersensitivity, GCR1 may act as a negative regulator of GPA1-mediated ABA responses in guard cells. ..
  26. Jain S, Akiyama K, Takata R, Ohguchi T. Signaling via the G protein alpha subunit FGA2 is necessary for pathogenesis in Fusarium oxysporum. FEMS Microbiol Lett. 2005;243:165-72 pubmed
    ..The fga1/fga2 double disruptants showed phenotypic alterations similar to the fga1 or fga2 single disruptants, but increase of heat resistance was much more pronounced than in each single disruptant. ..
  27. Trusov Y, Rookes J, Chakravorty D, Armour D, Schenk P, Botella J. Heterotrimeric G proteins facilitate Arabidopsis resistance to necrotrophic pathogens and are involved in jasmonate signaling. Plant Physiol. 2006;140:210-20 pubmed
    ..We hypothesize that Gbetagamma acts as a direct or indirect enhancer of the jasmonate signaling pathway in plants. ..
  28. Pandey S, Chen J, Jones A, Assmann S. G-protein complex mutants are hypersensitive to abscisic acid regulation of germination and postgermination development. Plant Physiol. 2006;141:243-56 pubmed
    ..Thus, cell- and tissue-specific functional interaction in response to a given signal such as ABA may determine the distinct pathways regulated by the individual members of the G-protein complex. ..
  29. Du Q, Macara I. Mammalian Pins is a conformational switch that links NuMA to heterotrimeric G proteins. Cell. 2004;119:503-16 pubmed
    ..We propose that a related switch mechanism might operate in asymmetric cell divisions in the fly and nematode. ..
  30. Chen J, Gao Y, Jones A. Differential roles of Arabidopsis heterotrimeric G-protein subunits in modulating cell division in roots. Plant Physiol. 2006;141:887-97 pubmed
    ..These results suggest that Arabidopsis heterotrimeric G-protein subunits have differential and opposing roles in the modulation of cell division in roots. ..
  31. Umino Y, Solessio E, Barlow R. Speed, spatial, and temporal tuning of rod and cone vision in mouse. J Neurosci. 2008;28:189-98 pubmed publisher
    ..This parametric study characterizes the functional properties of the mouse visual system, revealing the rod and cone contributions to contrast sensitivity and to the temporal processing of visual stimuli. ..
  32. Han K, Seo J, Yu J. Regulators of G-protein signalling in Aspergillus nidulans: RgsA downregulates stress response and stimulates asexual sporulation through attenuation of GanB (Galpha) signalling. Mol Microbiol. 2004;53:529-40 pubmed
    ..Our findings define a second and specific RGS-Galpha pair in A. nidulans, which may govern upstream regulation of fungal cellular responses to environmental changes. ..
  33. Schmoll M, Schuster A, Silva R, Kubicek C. The G-alpha protein GNA3 of Hypocrea jecorina (Anamorph Trichoderma reesei) regulates cellulase gene expression in the presence of light. Eukaryot Cell. 2009;8:410-20 pubmed publisher
    ..Our data for the first time imply an involvement of a G-alpha subunit in a light-dependent signaling event in fungi...
  34. Adjobo Hermans M, Goedhart J, Gadella T. Plant G protein heterotrimers require dual lipidation motifs of Galpha and Ggamma and do not dissociate upon activation. J Cell Sci. 2006;119:5087-97 pubmed
    ..Importantly, rendering GPalpha1 constitutively active did not cause a FRET decrease in the heterotrimer, suggesting no dissociation upon GPalpha1 activation. ..
  35. Colombo S, Ronchetti D, Thevelein J, Winderickx J, Martegani E. Activation state of the Ras2 protein and glucose-induced signaling in Saccharomyces cerevisiae. J Biol Chem. 2004;279:46715-22 pubmed
    ..Strains with reduced feedback inhibition on cAMP synthesis also display elevated basal and induced Ras2 GTP loading consistent with the Ras2 protein acting as a target of the feedback-inhibition mechanism. ..
  36. Sánchez Blázquez P, Rodríguez Muñoz M, Montero C, Garzón J. RGS-Rz and RGS9-2 proteins control mu-opioid receptor desensitisation in CNS: the role of activated Galphaz subunits. Neuropharmacology. 2005;48:134-50 pubmed
    ..g., through the activity of RGS9-2 proteins. ..
  37. Van Eps N, Oldham W, Hamm H, Hubbell W. Structural and dynamical changes in an alpha-subunit of a heterotrimeric G protein along the activation pathway. Proc Natl Acad Sci U S A. 2006;103:16194-9 pubmed
    ..A previously unreported activation-dependent change in alpha4, distant from the interaction surface, supports a role for this helix in effector binding. ..
  38. Komon Zelazowska M, Neuhof T, Dieckmann R, von Döhren H, Herrera Estrella A, Kubicek C, et al. Formation of atroviridin by Hypocrea atroviridis is conidiation associated and positively regulated by blue light and the G protein GNA3. Eukaryot Cell. 2007;6:2332-42 pubmed
    ..Our data show that formation of atroviridin by H. atroviridis occurs in a sporulation-associated manner but is uncoupled from it at the stage of GNA3...
  39. Gotta M, Dong Y, Peterson Y, Lanier S, Ahringer J. Asymmetrically distributed C. elegans homologs of AGS3/PINS control spindle position in the early embryo. Curr Biol. 2003;13:1029-37 pubmed
    ..Our results suggest that GPR-1 and/or GPR-2 control an asymmetry in forces exerted on the spindle poles by asymmetrically modulating the activity of the heterotrimeric G protein in response to a signal from the PAR proteins. ..
  40. Ongay Larios L, Saviñón Tejeda A, Williamson M, Durán Avelar M, Coria R. The Leu-132 of the Ste4(Gbeta) subunit is essential for proper coupling of the G protein with the Ste2 alpha factor receptor during the mating pheromone response in yeast. FEBS Lett. 2000;467:22-6 pubmed
  41. Parsley T, Segers G, Nuss D, Dawe A. Analysis of altered G-protein subunit accumulation in Cryphonectria parasitica reveals a third Galpha homologue. Curr Genet. 2003;43:24-33 pubmed
    ..We describe the sequence of a new Galpha subunit, CPG-3, that is most similar to three other filamentous fungal Galpha proteins that form a phylogenetically distinct grouping. ..
  42. Harashima T, Heitman J. The Galpha protein Gpa2 controls yeast differentiation by interacting with kelch repeat proteins that mimic Gbeta subunits. Mol Cell. 2002;10:163-73 pubmed
    ..Our studies demonstrate that Gpa2 signals in conjunction with Gbeta structural mimics and that homologous G protein subunits or effectors may be conserved in multicellular eukaryotes. ..
  43. Okamoto H, Matsui M, Deng X. Overexpression of the heterotrimeric G-protein alpha-subunit enhances phytochrome-mediated inhibition of hypocotyl elongation in Arabidopsis. Plant Cell. 2001;13:1639-52 pubmed
    ..Thus, our results support the involvement of a heterotrimeric G-protein in the light regulation of Arabidopsis seedling development. ..
  44. Ullah H, Chen J, Young J, Im K, Sussman M, Jones A. Modulation of cell proliferation by heterotrimeric G protein in Arabidopsis. Science. 2001;292:2066-9 pubmed
    ..Results from loss of function and ectopic expression and activation of GPA1 indicate that this subunit is a positive modulator of cell division in plants. ..
  45. Versele M, de Winde J, Thevelein J. A novel regulator of G protein signalling in yeast, Rgs2, downregulates glucose-activation of the cAMP pathway through direct inhibition of Gpa2. EMBO J. 1999;18:5577-91 pubmed
    ..Moreover, Rgs2 and Sst2 exert specific, non-overlapping functions, and deletion mutants in Rgs2 and Sst2 are complemented to some extent by different mammalian RGS proteins. ..
  46. Li E, Meldrum E, Stratton H, Stone D. Substitutions in the pheromone-responsive Gbeta protein of Saccharomyces cerevisiae confer a defect in recovery from pheromone treatment. Genetics. 1998;148:947-61 pubmed
    ..On the basis of these observations, we propose that Gpa1p-mediated adaptation involves the binding of an unknown negative regulator to Gbetagamma. ..
  47. Kimple R, Willard F, Hains M, Jones M, Nweke G, Siderovski D. Guanine nucleotide dissociation inhibitor activity of the triple GoLoco motif protein G18: alanine-to-aspartate mutation restores function to an inactive second GoLoco motif. Biochem J. 2004;378:801-8 pubmed
  48. Yun C, Tamaki H, Nakayama R, Yamamoto K, Kumagai H. G-protein coupled receptor from yeast Saccharomyces cerevisiae. Biochem Biophys Res Commun. 1997;240:287-92 pubmed
    ..It is likely that a Gpr1p monitors the extracellular signal such as nutrition and transduce it via Gpa2p a possible positive regulator of cAMP level. ..
  49. Regenfelder E, Spellig T, Hartmann A, Lauenstein S, Bölker M, Kahmann R. G proteins in Ustilago maydis: transmission of multiple signals?. EMBO J. 1997;16:1934-42 pubmed
    ..Surprisingly, Gpa3 is also required for pathogenic development, although pheromone signalling is not essential for this process...
  50. Chen J, Willard F, Huang J, Liang J, Chasse S, Jones A, et al. A seven-transmembrane RGS protein that modulates plant cell proliferation. Science. 2003;301:1728-31 pubmed
    ..These findings suggest that AtRGS1 is a critical modulator of plant cell proliferation. ..
  51. Saviñón Tejeda A, Ongay Larios L, Valdés Rodríguez J, Coria R. The KlGpa1 gene encodes a G-protein alpha subunit that is a positive control element in the mating pathway of the budding yeast Kluyveromyces lactis. J Bacteriol. 2001;183:229-34 pubmed
    ..The DeltaKlgpa1 DeltaKlgpa2 double mutant, although viable, showed the mating deficiency observed in the single DeltaKlgpa1 mutant. ..
  52. Zhao J, Wang X. Arabidopsis phospholipase Dalpha1 interacts with the heterotrimeric G-protein alpha-subunit through a motif analogous to the DRY motif in G-protein-coupled receptors. J Biol Chem. 2004;279:1794-800 pubmed
  53. Thevelein J, de Winde J. Novel sensing mechanisms and targets for the cAMP-protein kinase A pathway in the yeast Saccharomyces cerevisiae. Mol Microbiol. 1999;33:904-18 pubmed
    ..Cln3 appears to play a crucial role in the connection between the availability of certain nutrients and Cdc28 kinase activity, but it remains to be clarified which nutrient-controlled pathways control Cln3 levels. ..