SAG binds p-MII to form p-MII:SAG

Stable Identifier
R-HSA-2581488
Type
Reaction [binding]
Species
Homo sapiens
Compartment
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Although phosphorylation of activated rhodopsin (MII) reduces transducin activation, complete deactivation occurs only after arrestin (S-antigen or SAG, Yamaki et al. 1988) binds to and sterically caps MII. SAG is capable of binding unphosphorylated MII, but with very low probability. Binding affinity increases greatly upon phosphorylation. Binding of SAG generally occurs after MII has been phosphorylated ~3 times, and binding prevents further phosphorylation. Interestingly, rods express a small amount of a splice variant of SAG, P44, but its function is not yet known. Defects in SAG cause Oguchi type 1 disease (CSNBO1; MIM:258100), a recessive form of congenital stationary night blindness characterized by impaired scotopic vision (Fuchs et al. 1995).

Literature References
PubMed ID Title Journal Year
7670478 A homozygous 1-base pair deletion in the arrestin gene is a frequent cause of Oguchi disease in Japanese

Fuchs, S, Nakazawa, M, Maw, M, Tamai, M, Oguchi, Y, Gal, A

Nat. Genet. 1995
3164688 The sequence of human retinal S-antigen reveals similarities with alpha-transducin.

Yamaki, K, Tsuda, M, Shinohara, T

FEBS Lett 1988
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