Fig. 8. Biochemical analysis of interaction between PrP^C and LRP1 on sensory neurons. (A) Immunoblot for PrP and Thy-1 of sequential immunoprecipitates (IP) of surface then internal antigen using antibody against PrP^C or LRP1. The large arrow denotes the major 37-kDa di-glycosylated surface form of PrP^C, the mid-size arrow shows monoglycosylated PrP^C, and the small arrow shows non-glycosylated 23-kDa PrP^C. PrP immunoblots are from the same gel, with duplicate samples run separately for Thy-1. (B) Immunoprecipitates for internal PrP or LRP1 (from part A) were diluted in endo H digestion buffer and either digested or not with the glycosidase, as indicated, before being immunoblotted for PrP. Arrows denote the relevant PrP^C glycoforms as in A; the asterisk denotes the (slanted) band of endo H enzyme that binds antibodies nonspecifically.