Toward the identification of the anandamide transporter: A proteomics-based approach
Abstract
The long-chain fatty acid anandamide (AEA) is an endogenous agonist for the cannabinoid receptors CB1 and CB2. Due to an overwhelming number of physiologically- and pathophysiologically-relevant implications for endocannabinoid signaling with regard to pain, mood, appetite, and the immune response, cannabinoid receptor signaling is an active research area. Anandamide is a putative neurotransmitter, and as such, there must exist mechanisms for its biosynthesis, release, and uptake from the synaptic space. Harnessing endogenous AEA by selectively preventing its uptake could have therapeutic benefit in the areas listed above. However, in order to exploit cannabinoid signaling in this way, we must better understand AEA uptake and metabolism. After on-demand synthesis and release into the extracellular space, AEA is transported into cells via an unknown process and metabolized by fatty acid amide hydrolase (FAAH) into arachidonic acid and ethanolamine. Our lab has previously shown that AEA metabolites are then recycled to caveolae, which are invaginations in the plasma membrane rich in cholesterol and sphingolipids and are believed to be involved in coordinating extra- and intracellular signaling events. Despite the information available regarding AEA synthesis and metabolism, little is known about the process by which AEA is transported into the cell. AEA uptake has been identified in several different cell lines as a temperature-dependent and saturable process that is independent of ion-gradients or energy. These characteristics correspond well with a facilitated process. Thus, it is likely that AEA uptake is a dynamic process involving multiple components, including a specific protein carrier and/or binding protein. Additionally, data from our lab indicate that AEA uptake occurs via a caveolae-related endocytic pathway. The research described herein was focused on identifying the protein(s) responsible for AEA uptake and metabolite trafficking. Utilizing a proteomics-based approach, we have identified ERp57 as likely playing a role in AEA metabolite trafficking and possibly regulation of FAAH transcription. Additional studies were focused on identifying the putative AEA transporter, a target for the potent and selective AEA uptake inhibitor LY2318912.
Degree
Ph.D.
Advisors
Barker, Purdue University.
Subject Area
Neurosciences|Cellular biology
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