S-arrestin
Domain
The C-terminus of isoform A interferes with binding to non-phosphorylated RHO. Interaction with phosphorylated RHO triggers displacement of the C-terminus and leads to a conformation change that mediates high-affinity RHO binding. Isoform B is C-terminally truncated and is therefore already in the optimal conformation for RHO binding.
Function
Binds to photoactivated, phosphorylated RHO and terminates RHO signaling via G-proteins by competing with G-proteins for the same binding site on RHO (PubMed:25205354, PubMed:8003967). May play a role in preventing light-dependent degeneration of retinal photoreceptor cells (By similarity).
Sequence Similarities
Belongs to the arrestin family.
Tissue Specificity
Detected in retina, in rod photoreceptor cells (at protein level) (PubMed:7515057, PubMed:8003967).
Cellular localization
- Isoform A
- Cell projection
- Cilium
- Photoreceptor outer segment
- Membrane
- Peripheral membrane protein
- Highly expressed in photoreceptor outer segments in light-exposed retina (PubMed:7515057). Evenly distributed throughout rod photoreceptor cells in dark-adapted retina (PubMed:7515057). Predominantly dectected at the proximal region of photoreceptor outer segments, near disk membranes (By similarity).
- Isoform B
- Cell projection
- Cilium
- Photoreceptor outer segment
- Membrane
- Peripheral membrane protein
Alternative names
S-arrestin, 48 kDa protein, Retinal S-antigen, Rod photoreceptor arrestin, S-AG, SAG