Promotes the cell surface stability of rhomboid 5 homologs and prevents their degradation via the endolysosomal pathway. By acting on rhomboid 5 homologs, involved in ADAM17-mediated ligand shedding (By similarity). Negatively regulates the Wnt/beta-catenin signaling pathway (PubMed:19572019). Maternally expressed transcript, detected in the animal pole at 4 hpf. At 5.5 hpf, widely expressed at 50% epiboly. At 24 hpf, widely expressed, with high levels in the otic vesicle. At 36 hpf, weak expression in the tail.