Fig. 2. Mutants that affect retrieval of Pep12p. (A) GFP–Pep12p bearing the Sso1p TMD and a mutant FSD signal (F20L) is in punctate PGE structures with either the F6L or I71T mutations, but with both it is on vacuolar membranes. (B) Sucrose gradient fractionation of Δpep12 cells expressing FSD– Pep12p, with its own TMD, with or without the F6L/I71T mutations. Fraction 1 is the top of the gradient. The positions of PGEs and vacuolar membranes, identified by the presence of Tlg1p and Vam3p, respectively (), are indicated. PVEs, defined by Pep12p itself, run in the centre of the gradient. Note that the extracts were pre-cleared by medium-speed centrifugation, resulting in substantial under-representation of vacuoles on the gradients. (C) Quantitation of the indicated proteins in gradient fractions. The left hand panel corresponds to the gradients in (B).