Retinal attachment instability is diversified among mammalian melanopsins

Hisao Tsukamoto, Yoshihiro Kubo, David L. Farrens, Mitsumasa Koyanagi, Akihisa Terakita, Yuji Furutani

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


Melanopsins play a key role in non-visual photoreception in mammals. Their close phylogenetic relationship to the photopigments in invertebrate visual cells suggests they have evolved to acquire molecular characteristics that are more suited for their non-visual functions. Here we set out to identify such characteristics by comparing the molecular properties of mammalian melanopsin to those of invertebrate melanopsin and visual pigment. Our data show that the Schiff base linking the chromophore retinal to the protein is more susceptive to spontaneous cleavage in mammalian melanopsins. We also find this stability is highly diversified between mammalian species, being particularly unstable for human melanopsin. Through mutagenesis analyses, we find that this diversified stability is mainly due to parallel amino acid substitutions in extracellular regions. We propose that the different stability of the retinal attachment in melanopsins may contribute to functional tuning of non-visual photoreception in mammals.

Original languageEnglish (US)
Pages (from-to)27176-27187
Number of pages12
JournalJournal of Biological Chemistry
Issue number45
StatePublished - Nov 6 2015

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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