Table I

Selected proteins involved in phototransduction and visual cycle in rods and cones

The number of unique peptides used for the identification is given. The protein to rhodopsin ratio was estimated by APEX analysis. NF, not found in the APEX list of 150 most abundant proteins from the primary data set.

ProteinUnique peptidesProtein to rhodopsin ratio (APEX)
        Rhodopsin (Rho)101
        Transducin, α-1 subunit280.250
        Transducin, β-1 subunit150.106
        Transducin, γ-T1 subunit70.039
        Rod cGMP-specific 3′,5′-cyclic phosphodiesterase α subunit440.070
        Rod cGMP-specific 3′,5′-cyclic phosphodiesterase β subunit510.077
        cGMP-gated cation channel α subunit (CNGA1)240.049
        cGMP-gated cation channel 240-kDa β subunit (CNGB1)370.060
        Regulator of G protein signaling 9 (RGS9)330.021
        Guanine nucleotide-binding protein, β-5 subunit150.017
        Regulator of G protein signaling 9-binding protein (R9AP)120.010
        Retinal guanylyl cyclase 1 (GC1)390.047
        Retinal guanylyl cyclase 2 (GC2)230.008
        Rhodopsin kinase220.047
        Sodium/calcium-potassium exchanger 1 (NCKX1)160.030
        Splice isoform B of S-arrestin360.120
        Calmodulin 13NF
        Protein phosphatase 2 α40.004
        Arrestin 3 (X-arrestin)40.007
        Blue-sensitive opsin20.023
        cGMP-gated cation channel α3 (CNGA3)6NF
        Cone cGMP-specific 3′,5′-cyclic phosphodiesterase α subunit270.016
        Red opsin80.057
        Retina G protein-coupled receptor kinase 740.005
        Sodium/calcium-potassium exchanger 23NF
        Transducin α-2 subunit160.054
        Transducin γ-T2 subunit2NF
Visual/retinoid cycle
    All-trans-retinol dehydrogenase70.021
    Cellular retinaldehyde-binding protein120.031
    Interphotoreceptor retinoid-binding protein (IRBP)460.061
    Retinal pigment epithelium-specific 65-kDa protein3NF