Mapping the interaction site of prion protein and Sho

The cellular prion protein (PrPC) is a highly conserved protein among mammals and is considered to have important cellular functions. Despite decades of intensive research, however, the physiological function of PrPC remains unclear. Sho (Shadoo, shadow of prion protein) and PrPC have similar N-terminals, which suggests that the two proteins share biological functions. Using truncation mutants of both proteins and yeast two-hybrid analysis, with validation by co-immunoprecipitation and surface plasmon resonance (SPR), we have identified an interaction between Sho 61-77 and PrPC 108-126 domains. This indicates that Sho may play a role in the physiological function of PrPC and prion pathogenesis.