Regulatory subunit of protein phosphatase 6 (PP6). May function as a scaffolding PP6 subunit (By similarity). Protein phosphatase 6 (PP6) holoenzyme is proposed to be a heterotrimeric complex formed by the catalytic subunit, a SAPS domain-containing subunit (PP6R) and an ankyrin repeat-domain containing regulatory subunit (ARS). Belongs to the SAPS family.