Identification of critical phosphorylation sites on the carboxy tail of melanopsin

Joseph R. Blasic, Vanessa Matos-Cruz, Devyani Ujla, Evan G. Cameron, Samer Hattar, Marnie E. Halpern, Phyllis R. Robinson

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


Light-activated opsins undergo carboxy-terminal phosphorylation, which contributes to the deactivation of their photoresponse. The photopigment melanopsin possesses an unusually long carboxy tail containing 37 serine and threonine sites that are potential sites for phosphorylation by a G-protein dependent kinase (GRK). Here, we show that a small cluster of six to seven sites is sufficient for deactivation of light-activated mouse melanopsin. Surprisingly, these sites are distinct from those that regulate deactivation of rhodopsin. In zebrafish, there are five different melanopsin genes that encode proteins with distinct carboxy-terminal domains. Naturally occurring changes in the same cluster of phosphorylatable amino acids provides diversity in the deactivation kinetics of the zebrafish proteins. These results suggest that variation in phosphorylation sites provides flexibility in the duration and kinetics of melanopsin-mediated light responses.

Original languageEnglish (US)
Pages (from-to)2644-2649
Number of pages6
Issue number16
StatePublished - Apr 29 2014
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry


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