Multiple palmitoyl acyltransferases modify DAT palmitoylation (803.5)

Abstract

The dopamine transporter (DAT) mediates the reuptake of synaptic dopamine, thus regulating dopaminergic neurotransmission. DAT undergoes palmitoylation in which a saturated 16‐carbon palmitate group is linked to cysteine via a thioester bond. Palmitoylation regulates diverse aspects of neuronal protein trafficking and function, but its role in DAT function is poorly understood. Palmitoylation is a reversible process in which the protein undergoes cycles of palmitoylation and depalmitoylation catalyzed by palmitoyl acyltransferases (PATs) and palmitoyl‐protein thioesterases (PPTs). The 23 member family of DHHC (Asp‐His‐His‐Cys) proteins, identified as PATs, remains poorly characterized and the identities of the PATs and PPTs involved in the regulation of DAT palmitoylation are unknown. To address this question, we co‐expressed each PAT individually with DAT and assessed DAT palmitoylation, total expression, and transport activity. Preliminary results indicate that specific neuronal‐linked enzymes DHHC2, DHHC3, DHHC8, DHHC15, and DHHC17 increase DAT palmitoylation, while several other DHHC enzymes have no effect. Furthermore, DHHC enzymes found to increase DAT palmitoylation also increase total DAT levels, while treatment with the PAT inhibitor, 2‐bromopalmitate, led to DAT degradation. These findings suggest that palmitoylation enhances total DAT levels, opposing its degradation. Grant Funding Source: Supported by DA 13147, DA 031991, EPS 0184442