Insulin receptor regulates photoreceptor CNG channel activity

Vivek K. Gupta, Ammaji Rajala, Raju V. S. Rajala

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)


Photoreceptor cyclic nucleotide gated (CNG) channels are critical elements in phototransduction and light adaptation. Here we report that insulin receptor (IR), an integral membrane protein, directly phosphorylates the CNGA1 subunit of CNG channels that in turn affects the function of these channels negatively. The IR phosphorylates Tyr⁴⁹⁸ and Tyr⁵⁰³ residues on CNGA1 that are situated at the membrane-cytoplasmic interface. The IR tyrosine kinase activity is essential for the inhibition of CNG channel. To maintain the channels in an off state, it is necessary not only to have a precise balance of the cGMP levels but also to have a control on the cGMP sensitivity of the CNG channels itself. In this study, we observed that the channel opens at a lower concentration of cGMP in IR⁻/⁻ mice. These studies suggest that IR regulates the modulation of CNG channel activity in vivo.
Original languageEnglish
Pages (from-to)E1363-E1372
Number of pages10
JournalAmerican journal of physiology - endocrinology and metabolism
Issue number11
Publication statusPublished - 2012
Externally publishedYes


  • cyclic nucleotide gated channels
  • insulin receptor
  • rod outer segments
  • phosphorylation
  • guanosine 3´,5´-cyclic monophosphate


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