The activities of the E3 ubiquitin ligase COP1/SPA, a key repressor in light signaling

Curr Opin Plant Biol. 2017 Jun:37:63-69. doi: 10.1016/j.pbi.2017.03.015. Epub 2017 Apr 21.


Light is a critical signal to integrate plant growth and development with the environment. Downstream of photoreceptors, the E3 ubiquitin ligase COP1/SPA is a key repressor of photomorphogenesis which targets many positive regulators of light signaling, mainly transcription factors, for degradation in darkness. In light-grown plants COP1/SPA activity is repressed, allowing light responses to occur. This review provides an overview on our current knowledge on COP1/SPA repressor function, focusing in particular on the roles of the respective protein domains and the mechanisms of light-induced inactivation of COP1/SPA. Moreover, we summarize how COP1 activity is regulated by other interacting proteins, such as a SUMO E3 ligase and Phytochrome-Interacting Factors (PIFs), as well as by hormones. At last, several novel functions of COP1 that were recently revealed are included.

Publication types

  • Review

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / metabolism
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism
  • Gene Expression Regulation, Plant
  • Light Signal Transduction / genetics
  • Light Signal Transduction / physiology
  • Light*
  • Ubiquitin-Protein Ligases / genetics
  • Ubiquitin-Protein Ligases / metabolism*


  • Arabidopsis Proteins
  • AT2G32950 protein, Arabidopsis
  • Ubiquitin-Protein Ligases