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Palmitoylation regulates diverse aspects of neuronal protein trafficking and function. Here a global characterization of rat neural palmitoyl-proteomes identifies most of the known neural palmitoyl proteins--68 in total, plus more [...]

The yeast chitin synthase Chs3 provides a well-studied paradigm for polytopic membrane protein trafficking. In this study, high-throughput analysis of the yeast deletion collection identifies a requirement for Pfa4, which is an uncharacterized protein with protein acyl transferase (PAT) homology, in Chs3 transport. PATs, which are the enzymatic mediators of protein palmitoylation, have only recently been discovered, and few substrates have been identified. We find that Chs3 is palmitoylated and that this modification is Pfa4-dependent, indicating that Pfa4 is indeed a PAT. Chs3 palmitoylation is required for ER export, but not for interaction with its dedicated ER chaperone, Chs7. Nonetheless, both palmitoylation and chaperone association are required to prevent the accumulation of Chs3 in high--molecular mass aggregates at the ER. Our data indicate that palmitoylation is necessary for Chs3 to attain an export-competent conformation, and suggest the possibility of a more general role for palmitoylation in the ER quality control of polytopic membrane proteins.

A new proteomic methodology is used that purifies and identifies palmitoylated proteins to characterize the palmitoyl proteome of the yeast Saccharomyces cerevisiae. This approach identifies 12 of the 15 known palmitoyl proteins plus many new palmitoyl proteins.

Investigates the recycling of a-factor receptor (Ste3p) in yeasts. Effects of medium ligand withdrawal on internalized receptor; Participation of Ste3p on endocytosis; Presentation of Ste3p endocytic modes to generate polarized receptor distribution.