Cyanobacteriochrome SesA is a diguanylate cyclase that induces cell aggregation in Thermosynechococcus

Gen Enomoto, Ryouhei Nomura, Takashi Shimada, Ni Ni Win, Rei Narikawa, Masahiko Ikeuchi

Research output: Contribution to journalArticlepeer-review

87 Citations (Scopus)


Cyanobacteria have unique photoreceptors, cyanobacteriochromes, that show diverse spectral properties to sense near-UV/ visible lights. Certain cyanobacteriochromes have been shown to regulate cellular phototaxis or chromatic acclimation of photosynthetic pigments. Some cyanobacteriochromes have output domains involved in bacterial signaling using a second messenger cyclic dimeric GMP (c-di-GMP), but its role in cyanobacteria remains elusive. Here, we characterize the recombinant Tlr0924 from a thermophilic cyanobacterium Thermosynechococcus elongatus, which was expressed in a cyanobacterial system. The protein reversibly photoconverts between blue- and green-absorbing forms, which is consistent with the protein prepared from Escherichia coli, and has diguanylate cyclase activity, which is enhanced 38-fold by blue light compared with green light. Therefore, Tlr0924 is a blue light-activated diguanylate cyclase. The protein's relatively low affinity (10.5 mM) for Mg2+, which is essential for diguanylate cyclase activity, suggests that Mg2+might also regulate c-di-GMP signaling. Finally, we show that blue light irradiation under low temperature is responsible for Thermosynechococcus vulcanus cell aggregation, which is abolished when tlr0924 is disrupted, suggesting that Tlr0924 mediates blue light-induced cell aggregation by producing c-di-GMP. Given our results, we propose the name "sesA (sessility-A)" for tlr0924. This is the first report for cyanobacteriochrome-dependent regulation of a sessile/planktonic lifestyle in cyanobacteria via c-di-GMP.

Original languageEnglish
Pages (from-to)24801-24809
Number of pages9
JournalJournal of Biological Chemistry
Issue number36
Publication statusPublished - 2014
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology


Dive into the research topics of 'Cyanobacteriochrome SesA is a diguanylate cyclase that induces cell aggregation in Thermosynechococcus'. Together they form a unique fingerprint.

Cite this