{"doi":"10.3389/fnmol.2020.00089","title":"Ex vivo Quantitative Proteomic Analysis of Serotonin Transporter Interactome: Network Impact of the SERT Ala56 Coding Variant","abstract":"Altered serotonin (5-HT) signaling is associated with multiple brain disorders, including major depressive disorder (MDD), obsessive-compulsive disorder (OCD), and autism spectrum disorder (ASD). The presynaptic, high-affinity 5-HT transporter (SERT) tightly regulates 5-HT clearance after release from serotonergic neurons in the brain and enteric nervous systems, among other sites. Accumulating evidence suggests that SERT is dynamically regulated in distinct activity states as a result of environmental and intracellular stimuli, with regulation perturbed by disease-associated coding variants. Our lab identified a rare, hypermorphic SERT coding substitution, Gly56Ala, in subjects with ASD, finding that the Ala56 variant stabilizes a high-affinity outward-facing conformation, leading to elevated 5-HT uptake, termed SERT* state, in vitro and in vivo. Hyperactive SERT Ala56 appears to preclude further activity enhancements by p38 MAPK and can be normalized by pharmacological p38⍺ MAPK inhibition, consistent with SERT Ala56 mimicking, constitutively, a high-activity conformation entered into transiently by p38⍺ MAPK activation. As SERT has been found to interact with a number of regulatory proteins, we hypothesize that changes in SERT-interacting proteins (SIPs) support the shift of SERT into the SERT* state that can best be captured comparing SERT Ala56 protein complexes with those of wildtype SERT and by defining specific interactions through comparisons to protein complexes recovered in SERT-/- mice. Using quantitative proteomics-based approaches, we identify a number of proteins previously shown to interact with SERT, as well as a number of SIPs, that demonstrate both SERT specificity and sensitivity to the Gly56Ala substitution. Network analysis of our findings uncovers a number of ASD-associated proteins, consistent with long-standing evidence of serotonergic contributions to ASD. Further investigation of these SIPs, and the pathways they engage, may afford a greater understanding of ASD as well as other brain and peripheral disorders associated with perturbed 5-HT signaling.","journal":"Frontiers in Molecular Neuroscience","year":2020,"id":99959,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":29,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9518,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2020-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":491594,"name":"Matthew J. Robson","orcid":"0000-0002-3277-3062","position":1,"is_corresponding":false},{"id":491595,"name":"Ran Ye","orcid":"0000-0003-0914-234X","position":2,"is_corresponding":false},{"id":279679,"name":"Kristie L. Rose","orcid":null,"position":3,"is_corresponding":false},{"id":390309,"name":"Kevin L. Schey","orcid":"0000-0002-3959-1712","position":4,"is_corresponding":false},{"id":459255,"name":"Randy Blakely","orcid":"0000-0002-2182-6966","position":5,"is_corresponding":false},{"id":492845,"name":"Meagan A. Quinlan","orcid":null,"position":0,"is_corresponding":true}],"reference_count":112,"raw_metadata":null,"created_at":"2026-07-18T22:38:35.493878Z","pmid":"32581705","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}