Selenoprotein P (SelP) precursor (probably mediates transport of the reduced form, hydrogen selenide (380aas) (Ganyc and Self, 2007). This mouse protein is 71% identical to the human ortholog.  More recently, an efficient selenium transport pathway of selenoprotein P utilizing a high-affinity ApoER2 receptor variant and being independent of selenocysteine lyasehas been studied (Mizuno et al. 2023).