Fig. 1. Arl1p is not directly involved in the recycling of GFP-Snc1p and the processing of vacuolar proteins. (A) GFP-Snc1p distribution in arl1-, gcs1- and ypt6-deleted yeast. The indicated deletion mutants of BY4741 (Invitrogen) were transformed with a plasmid expressing GFP-Snc1p. Transformants were grown to exponential phase and inspected under a Zeiss microscope. Maturation of vacuolar enzymes CPY (B) and ALP (C) in an arl1 mutant. Wild-type and arl1 mutant cells were grown, radiolabeled with [³⁵S]methionine and [³⁵S]cysteine at 37°C or 16°C and incubated for the indicated chase time (in minutes) before immunoprecipitation with anti-CPY (B) or anti-ALP (C) antibodies. Enzyme forms are indicated on the left. For CPY: p1, the core-glycosylated ER form; p2, outer-chain-glycosylated Golgi form; m, mature form resulting from proteolytic processing in the vacuole. For ALP: pro, proenzyme form of ALP; m, mature vacuolar form.