Prion-like protein that has PrP(C)-like neuroprotective activity. May act as a modulator for the biological actions of normal and abnormal PrP. Mainly expressed in brain (at protein level). In brain, it is highly expressed in the hippocampus and cerebellum and is also expressed at lower level in other areas of the brain including the cerebral cortex, the thalamus and the medulla. In hippocampus and cerebellum it is highly expressed in the cell bodies of pyramidal cells and Purkinje cells, respectively. Appears at embryonic day 16 and persists in early postnatal life and in the brains of adults (at protein level). Strongly down-regulated in prion-infected brains (at protein level). N-glycosylated. This protein is a candidate for 'Pi' factor, a PrP(C)-like protein able to compensate for the absence of PrPC in mice lacking Prnp. Belongs to the SPRN family.