Figure 5.

Endocytosis defects in las17Δ cells. (A) FM4-64 uptake by las17Δ cells. YMW171K (las17Δ) and YPH499 (WT) cells were grown to log phase in liquid YPD at 25°C and then concentrated and incubated for 15 min in 20 μM FM4-64 followed by a 45-min chase in fresh YPD. Cells were photographed using an FITC filter (top panel) or DIC optics (bottom panel). Bar, 5 μm. (B) Alpha factor internalization by las17Δ cells. las17Δ strain RH 4207 and its equivalent wild type were preincubated at 37°C for 15 min before the addition of ³⁵S-alpha factor. The samples were processed as described by Dulic et al. (1991). Results are from one of two independent experiments, which gave nearly identical results. ●, WT, 24°C; ▪, las17Δ, 24°C; ○, WT, 37°C; □, las17Δ, 37°C.