Since its discovery in 1999, important data have emerged in the biology of the first prion-like protein, doppel. As the function of the cellular prion protein is still rather unclear, with the exception of the involve- ment of its pathological isoform within the TSEs, the
study of the antagonistic roles of doppel and prion proteins in the neuronal cell survival remains of piv- otal interest to directly discern the functions of doppel.
Although these proteins share biochemical properties, doppel is unlikely to play a major role in prion dis- eases. The physiological function of doppel seems to be restricted to the male reproductive apparatus, in particular regulating male fertility. The functional involvement of doppel in a novel identified patho- logical scenario, such as tumors, in particular those deriving from glial cell transformation, would con- tribute in the near future to gain further insights into the molecular biology of such dramatic pathologies, pos- sibly with the improvement of the molecular-assisted diagnosis and treatment.
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