Phosphatase required to prevent light-induced retinal degeneration. H2O + O-phospho-L-seryl-[protein] = L-seryl-[protein] + phosphate H2O + O-phospho-L-threonyl-[protein] = L-threonyl-[protein] + phosphate Binds 2 manganese ions per subunit. Expressed in the visual system of the fly, as well as in the mushroom bodies of the central brain. Belongs to the PPP phosphatase family. Truncated N-terminus. Intron retention.