Gene Symbol: SPA1
Description: SPA (suppressor of phyA-105) protein family
Alias: AT2G46350, F11C10.3, SUPPRESSOR OF PHYA-105 1, SPA (suppressor of phyA-105) protein family
Species: thale cress

Top Publications

  1. Hoecker U, Xu Y, Quail P. SPA1: a new genetic locus involved in phytochrome A-specific signal transduction. Plant Cell. 1998;10:19-33 pubmed
    ..A new recessive mutant, designated spa1 (for suppressor of phyA-105), was isolated and mapped to the bottom of chromosome 2...
  2. Rolauffs S, Fackendahl P, Sahm J, Fiene G, Hoecker U. Arabidopsis COP1 and SPA genes are essential for plant elongation but not for acceleration of flowering time in response to a low red light to far-red light ratio. Plant Physiol. 2012;160:2015-27 pubmed publisher
    ..We propose that COP1/SPA activity, via LONG HYPOCOTYL IN FR LIGHT1, is required for shade-induced modulation of the auxin biosynthesis pathway and thereby enhances cell elongation in low R:FR. ..
  3. Lian H, He S, Zhang Y, Zhu D, Zhang J, Jia K, et al. Blue-light-dependent interaction of cryptochrome 1 with SPA1 defines a dynamic signaling mechanism. Genes Dev. 2011;25:1023-8 pubmed publisher
    ..Here, we report that CRY1 interacts physically with SPA1 in a blue-light-dependent manner...
  4. Saijo Y, Sullivan J, Wang H, Yang J, Shen Y, Rubio V, et al. The COP1-SPA1 interaction defines a critical step in phytochrome A-mediated regulation of HY5 activity. Genes Dev. 2003;17:2642-7 pubmed
    ..b>SPA1 is a repressor of phytochrome A-mediated responses to far-red light...
  5. Mallappa C, Singh A, Ram H, Chattopadhyay S. GBF1, a transcription factor of blue light signaling in Arabidopsis, is degraded in the dark by a proteasome-mediated pathway independent of COP1 and SPA1. J Biol Chem. 2008;283:35772-82 pubmed publisher
    ..and molecular interrelation of GBF1 with two well characterized negative regulators of light signaling, COP1 and SPA1, in photomorphogenic growth and light-regulated gene expression...
  6. Zhu D, Maier A, Lee J, Laubinger S, Saijo Y, Wang H, et al. Biochemical characterization of Arabidopsis complexes containing CONSTITUTIVELY PHOTOMORPHOGENIC1 and SUPPRESSOR OF PHYA proteins in light control of plant development. Plant Cell. 2008;20:2307-23 pubmed publisher
    ..This study thus provides an in-depth biochemical view of the SPA-COP1 E3 ligase complexes and offers new insights into the molecular basis for their distinct roles in the light control of plant development. ..
  7. Hoecker U, Tepperman J, Quail P. SPA1, a WD-repeat protein specific to phytochrome A signal transduction. Science. 1999;284:496-9 pubmed
    ..A component in this pathway, SPA1 (for "suppressor of phyA-105"), functions in repression of photomorphogenesis and is required for normal ..
  8. Zuo Z, Liu H, Liu B, Liu X, Lin C. Blue light-dependent interaction of CRY2 with SPA1 regulates COP1 activity and floral initiation in Arabidopsis. Curr Biol. 2011;21:841-7 pubmed publisher
    ..2) undergoes blue light-dependent interaction with the COP1-interacting protein SUPPRESSOR OF PHYTOCHROME A 1 (SPA1)...
  9. Chen H, Huang X, Gusmaroli G, Terzaghi W, Lau O, Yanagawa Y, et al. Arabidopsis CULLIN4-damaged DNA binding protein 1 interacts with CONSTITUTIVELY PHOTOMORPHOGENIC1-SUPPRESSOR OF PHYA complexes to regulate photomorphogenesis and flowering time. Plant Cell. 2010;22:108-23 pubmed publisher
    ..The interactions between DDB1 and COP1, SPA1, and SPA3 were disrupted by mutations in the WDXR motifs of MBP-COP1, His-SPA1, and His-SPA3...

More Information


  1. Seo H, Yang J, Ishikawa M, Bolle C, Ballesteros M, Chua N. LAF1 ubiquitination by COP1 controls photomorphogenesis and is stimulated by SPA1. Nature. 2003;423:995-9 pubmed
    ..The coiled-coil domain of SPA1, a negative regulator of phyA signalling, has no effect on COP1 auto-ubiquitination but facilitates LAF1 ..
  2. Hoecker U, Quail P. The phytochrome A-specific signaling intermediate SPA1 interacts directly with COP1, a constitutive repressor of light signaling in Arabidopsis. J Biol Chem. 2001;276:38173-8 pubmed
    b>SPA1 is a phytochrome A (phyA)-specific signaling intermediate that acts as a light-dependent repressor of photomorphogenesis in Arabidopsis seedlings...
  3. Yang J, Lin R, Hoecker U, Liu B, Xu L, Wang H. Repression of light signaling by Arabidopsis SPA1 involves post-translational regulation of HFR1 protein accumulation. Plant J. 2005;43:131-41 pubmed
    ..Arabidopsis SPA1, which encodes a protein structurally related to COP1, also represses light signaling under various light ..
  4. Maier A, Schrader A, Kokkelink L, Falke C, Welter B, Iniesto E, et al. Light and the E3 ubiquitin ligase COP1/SPA control the protein stability of the MYB transcription factors PAP1 and PAP2 involved in anthocyanin accumulation in Arabidopsis. Plant J. 2013;74:638-51 pubmed publisher
    ..Thus, our findings have identified mechanisms via which the COP1/SPA complex controls anthocyanin levels in Arabidopsis that may be useful for applications in biotechnology directed towards increasing anthocyanin content in plants. ..
  5. Laubinger S, Marchal V, Le Gourrierec J, Gentilhomme J, Wenkel S, Adrian J, et al. Arabidopsis SPA proteins regulate photoperiodic flowering and interact with the floral inducer CONSTANS to regulate its stability. Development. 2006;133:3213-22 pubmed
    ..Here, we demonstrate that SPA proteins are, moreover, essential for photoperiodic flowering. Mutations in SPA1 cause phyA-independent early flowering under short day (SD) but not long day (LD) conditions, and this phenotype is ..
  6. Gangappa S, Prasad V, Chattopadhyay S. Functional interconnection of MYC2 and SPA1 in the photomorphogenic seedling development of Arabidopsis. Plant Physiol. 2010;154:1210-9 pubmed publisher
    ..Arabidopsis (Arabidopsis thaliana) MYC2 directly binds to the G-box present in the SUPPRESSOR OF PHYTOCHROME A1 (SPA1) promoter and that it controls the expression of SPA1 in a COP1-dependent manner...
  7. Balcerowicz M, Fittinghoff K, Wirthmueller L, Maier A, Fackendahl P, Fiene G, et al. Light exposure of Arabidopsis seedlings causes rapid de-stabilization as well as selective post-translational inactivation of the repressor of photomorphogenesis SPA2. Plant J. 2011;65:712-23 pubmed publisher
    ..Genetic analysis has shown that the four members of the SPA gene family (SPA1-SPA4) have overlapping but distinct functions...
  8. Liu B, Zuo Z, Liu H, Liu X, Lin C. Arabidopsis cryptochrome 1 interacts with SPA1 to suppress COP1 activity in response to blue light. Genes Dev. 2011;25:1029-34 pubmed publisher
    ..receptor cryptochrome 1 (CRY1) undergoes blue-light-dependent interaction with the COP1-interacting protein SPA1 (SUPPRESSOR OF PHYTOCHROME A)...
  9. Hughes R, Vrana J, Song J, Tucker C. Light-dependent, dark-promoted interaction between Arabidopsis cryptochrome 1 and phytochrome B proteins. J Biol Chem. 2012;287:22165-72 pubmed publisher
    ..We hypothesize that in plants, the phyB/CRY1 interaction may mediate cross-talk between the red/far-red- and blue/UV-sensing pathways, enabling fine-tuning of light responses to different spectral inputs. ..
  10. Chen S, Wirthmueller L, Stauber J, Lory N, Holtkotte X, Leson L, et al. The functional divergence between SPA1 and SPA2 in Arabidopsis photomorphogenesis maps primarily to the respective N-terminal kinase-like domain. BMC Plant Biol. 2016;16:165 pubmed publisher
    ..In particular, SPA1 and SPA2 strongly differ in their responsiveness to light, while they have indistinguishable activities in darkness...
  11. Maier A, Hoecker U. COP1/SPA ubiquitin ligase complexes repress anthocyanin accumulation under low light and high light conditions. Plant Signal Behav. 2015;10:e970440 pubmed publisher
    ..However, since cop1 and spa mutants show a similar high-light responsiveness of anthocyanin accumulation as the wild type it remains to be resolved whether COP1/SPA is directly involved in the high-light response itself. ..
  12. Schrader A, Uhrig J. MIDGET cooperates with COP1 and SPA1 to repress flowering in Arabidopsis thaliana. Plant Signal Behav. 2013;8: pubmed publisher
    ..Here we show that in Arabidopsis thaliana, the MID protein similarly plays a role in COP1/SPA1-controlled repression of flowering under short-day conditions.
  13. Hajdu A, Ádám Ã, Sheerin D, Dobos O, Bernula P, Hiltbrunner A, et al. High-level expression and phosphorylation of phytochrome B modulates flowering time in Arabidopsis. Plant J. 2015;83:794-805 pubmed publisher
    ..CO in the evening by attenuating the activity of the CONSTITUTIVE PHOTOMORPHOGENIC 1-SUPPRESSOR OF PHYA-105 1 (COP1-SPA1) ubiquitin ligase complex, which promotes turnover of CO...
  14. Weidler G, Zur Oven Krockhaus S, Heunemann M, Orth C, Schleifenbaum F, Harter K, et al. Degradation of Arabidopsis CRY2 is regulated by SPA proteins and phytochrome A. Plant Cell. 2012;24:2610-23 pubmed publisher
    ..SPA) proteins are known to work in concert with COP1, and recently direct physical interaction between cry2 and SPA1 was demonstrated. Thus, we hypothesized that SPA proteins could also play a role in cry2 degradation...
  15. Zheng X, Wu S, Zhai H, Zhou P, Song M, Su L, et al. Arabidopsis phytochrome B promotes SPA1 nuclear accumulation to repress photomorphogenesis under far-red light. Plant Cell. 2013;25:115-33 pubmed publisher
    ..SUPPRESSOR OF PHYA-105 (SPA1) forms an E3 ubiquitin ligase complex with CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1), which is responsible for the ..
  16. Sheerin D, Menon C, Zur Oven Krockhaus S, Enderle B, Zhu L, Johnen P, et al. Light-activated phytochrome A and B interact with members of the SPA family to promote photomorphogenesis in Arabidopsis by reorganizing the COP1/SPA complex. Plant Cell. 2015;27:189-201 pubmed publisher
    ..Here, we show that light-activated phytochrome A (phyA) and phytochrome B (phyB) interact with SPA1 and other SPA proteins...
  17. Tepperman J, Hwang Y, Quail P. phyA dominates in transduction of red-light signals to rapidly responding genes at the initiation of Arabidopsis seedling de-etiolation. Plant J. 2006;48:728-42 pubmed
  18. Balcerowicz M, Kerner K, Schenkel C, Hoecker U. SPA Proteins Affect the Subcellular Localization of COP1 in the COP1/SPA Ubiquitin Ligase Complex during Photomorphogenesis. Plant Physiol. 2017;174:1314-1321 pubmed publisher
  19. Heijde M, Binkert M, Yin R, Ares Orpel F, Rizzini L, Van De Slijke E, et al. Constitutively active UVR8 photoreceptor variant in Arabidopsis. Proc Natl Acad Sci U S A. 2013;110:20326-31 pubmed publisher
    ..Whereas COP1, RUP1, and RUP2 are known to directly interact with UVR8, we show that SPA1 interacts with UVR8 indirectly through COP1...
  20. Khanna R, Shen Y, Toledo Ortiz G, Kikis E, Johannesson H, Hwang Y, et al. Functional profiling reveals that only a small number of phytochrome-regulated early-response genes in Arabidopsis are necessary for optimal deetiolation. Plant Cell. 2006;18:2157-71 pubmed
  21. Ishikawa M, Kiba T, Chua N. The Arabidopsis SPA1 gene is required for circadian clock function and photoperiodic flowering. Plant J. 2006;46:736-46 pubmed
    ..The SUPPRESSOR OF PHYA-105 (SPA1) acts as a negative regulator of phyA-mediated de-etiolation of young seedlings, but its roles in adult plants have ..
  22. Ruckle M, Burgoon L, Lawrence L, Sinkler C, Larkin R. Plastids are major regulators of light signaling in Arabidopsis. Plant Physiol. 2012;159:366-90 pubmed publisher
    ..We conclude that the integration of light and plastid signaling regulates a number of END genes that help optimize chloroplast function and that at least some END genes affect photosynthesis-related gene expression...
  23. Li X, Wang Q, Yu X, Liu H, Yang H, Zhao C, et al. Arabidopsis cryptochrome 2 (CRY2) functions by the photoactivation mechanism distinct from the tryptophan (trp) triad-dependent photoreduction. Proc Natl Acad Sci U S A. 2011;108:20844-9 pubmed publisher
    ..CRY2, which undergoes blue-light-dependent interaction with the CRY2-signaling proteins SUPPRESSOR OF PHYA 1 (SPA1) and cryptochrome-interaction basic helix-loop-helix 1 (CIB1), the constitutively active CRY2(W374A) interacts with ..
  24. Gangappa S, Maurya J, Yadav V, Chattopadhyay S. The regulation of the Z- and G-box containing promoters by light signaling components, SPA1 and MYC2, in Arabidopsis. PLoS ONE. 2013;8:e62194 pubmed publisher
    ..However, the role of downstream signaling components such as SPA1 and MYC2/ZBF1, which are functionally interrelated, remains unknown...
  25. Nixdorf M, Hoecker U. SPA1 and DET1 act together to control photomorphogenesis throughout plant development. Planta. 2010;231:825-33 pubmed publisher
    ..We report the isolation of a spa1 enhancer mutation that represents a novel, very weak allele of det1...
  26. Lu X, Zhou C, Xu P, Luo Q, Lian H, Yang H. Red-light-dependent interaction of phyB with SPA1 promotes COP1-SPA1 dissociation and photomorphogenic development in Arabidopsis. Mol Plant. 2015;8:467-78 pubmed publisher
    ..It has been demonstrated that SPA1 (SUPPRESSOR OF PHYTOCHROME A 1) associates with COP1 to promote COP1 activity and suppress photomorphogenesis...
  27. Zhu L, Bu Q, Xu X, Paik I, Huang X, Hoecker U, et al. CUL4 forms an E3 ligase with COP1 and SPA to promote light-induced degradation of PIF1. Nat Commun. 2015;6:7245 pubmed publisher
    ..COP1, SPA1 and CUL4 preferentially form complexes with the phosphorylated forms of PIF1 in response to light...
  28. Huang X, Ouyang X, Yang P, Lau O, Chen L, Wei N, et al. Conversion from CUL4-based COP1-SPA E3 apparatus to UVR8-COP1-SPA complexes underlies a distinct biochemical function of COP1 under UV-B. Proc Natl Acad Sci U S A. 2013;110:16669-74 pubmed publisher
  29. Xu X, Paik I, Zhu L, Bu Q, Huang X, Deng X, et al. PHYTOCHROME INTERACTING FACTOR1 Enhances the E3 Ligase Activity of CONSTITUTIVE PHOTOMORPHOGENIC1 to Synergistically Repress Photomorphogenesis in Arabidopsis. Plant Cell. 2014;26:1992-2006 pubmed
    ..PIF1 forms complexes with COP1, HY5, and SPA1 and enhances the substrate recruitment and autoubiquitylation and transubiquitylation activities of COP1...
  30. Saijo Y, Zhu D, Li J, Rubio V, Zhou Z, Shen Y, et al. Arabidopsis COP1/SPA1 complex and FHY1/FHY3 associate with distinct phosphorylated forms of phytochrome A in balancing light signaling. Mol Cell. 2008;31:607-13 pubmed publisher
    ..that the light signaling repressors SPA proteins contribute to COP1-mediated phyA degradation and that a COP1/SPA1 protein complex is tightly associated with phyA ubiquitination activity...
  31. Huang H, Yoo C, Bindbeutel R, Goldsworthy J, Tielking A, Alvarez S, et al. PCH1 integrates circadian and light-signaling pathways to control photoperiod-responsive growth in Arabidopsis. elife. 2016;5:e13292 pubmed publisher
    ..Thus, PCH1 is a new factor that regulates photoperiod-responsive growth by integrating the clock with light perception pathways through modulating daily phyB-signaling. ..
  32. Gangappa S, Chattopadhyay S. MYC2, a bHLH transcription factor, modulates the adult phenotype of SPA1. Plant Signal Behav. 2010;5:1650-2 pubmed publisher
    MYC2 and SPA1 are two key regulatory proteins that negatively regulate light-controlled Arabidopsis seedling development...
  33. Ranjan A, Fiene G, Fackendahl P, Hoecker U. The Arabidopsis repressor of light signaling SPA1 acts in the phloem to regulate seedling de-etiolation, leaf expansion and flowering time. Development. 2011;138:1851-62 pubmed publisher
    ..Here, we have investigated the function of the key repressor of photomorphogenesis SPA1 in different tissues of the plant by expressing GUS-SPA1 under the control of tissue-specific promoters in a spa ..
  34. Yang J, Wang H. The central coiled-coil domain and carboxyl-terminal WD-repeat domain of Arabidopsis SPA1 are responsible for mediating repression of light signaling. Plant J. 2006;47:564-76 pubmed
    ..Arabidopsis suppressor of phyA-105 (SPA1), which encodes a protein structurally related to COP1, also acts to repress photomorphogenesis under various light ..