srv2–14, but not
srv2Δ, mutations confer an endocytic defect. (A)
Endocytosis of radiolabeled pheromone in SRV2 (RH978)
and srv2–14 (RH3993) strains was measured at 24°C
(solid symbols) or 37°C (open symbols) after a 15-min
(SRV2, srv2–14) preincubation at the
indicated temperature. Endocytosis in srv2Δ (RH4008,
triangles) and SRV2 (RH3393, circles) was measured after
a 5-min preincubation at 24°C. (B) Accumulation of LY in
SRV2 (RH978) and srv2–14 (RH3993)
mutants grown at 24°C and preincubated for 15 min at 37°C prior to
addition of LY for 1 h. (C) Maturation of radiolabeled CPY was
measured in SRV2 (RH978) and srv2–14
(RH3993) mutants grown at 24°C and preincubated for 15 min at 37°C
prior to starting a pulse–chase experiment as described in MATERIALS
AND METHODS. p1, endoplasmic reticulum form of CPY; p2, Golgi-modified
form of CPY; m, mature vacuolar form of CPY.