Calcium-dependent regulator of light sensitivity of cGMP phosphodiesterase in rod outer segments. Control rhodopsin phosphorylation in a Ca(2+)-dependent manner. Sensitivity-modulating protein 202 S-modulin SMOD_RANCA MGNTKSGALSKEILEELQLNTKFTQEELCTWYQSFLKECPSGRISKKQFESIYSKFFPDADPKAYAQHVFRSFDANNDGTLDFKEYMIALMMTSSGKANQKLEWAFCLYDVDGNGTINKKEVLEIITAIFKMINAEDQKHLPEDENTPEKRTNKIWVYFGKKDDDKLTEGEFIQGIVKNKEILRLIQYEPQKVKDKLKEKKH