{"doi":"10.1016/j.jbc.2025.110446","title":"GoLoco/GPR motif-dependent regulation of Rap1GAP1 by Gαo is disrupted by Gαo encephalopathy variants","abstract":"G protein-coupled receptors (GPCRs) that couple to Gα i/o family members are major therapeutic targets. Among heterotrimeric G proteins, Gα o is the most abundant Gα subunit in the brain but the mechanistic pathways controlled by Gα o have not been thoroughly established. Understanding Gα o -mediated signalling pathways is especially critical given recent reports of a neurodevelopmental disorder ( GNAO1 encephalopathy) associated with mutations in the Gα o -encoding gene. To address this gap, we sought to uncover novel Gα o effectors using a proximity-based proteomics screen in differentiated PC12 cells. Our analysis revealed a diverse set of potential Gα o -GTP effector proteins including a Rap1 GTPase activating protein, Rap1GAP1. Regulation of Rap1GAP1 by G protein α subunits is controversial, with Rap1GAP1 reported to bind preferentially to Gα o -GDP via a GoLoco/G protein regulatory (GPR) motif. We establish that Gα o -GTP binds and regulates Rap1GAP1 activity and reveal a novel mechanism for Gα subunit recognition by Rap1GAP1 where the presence or absence of key contact residues in the GoLoco/GPR motif confer differential recognition of Gα o guanine nucleotide binding status. We also show that pathologic GNAO1 mutations disrupt this functional relationship by preventing the activated Gα subunit from attaining a conformation required for effector binding. These data resolve controversies in the literature regarding activation-dependent binding and regulation of Rap1GAP by Gα o and help establish Rap1GAP1a as a bone fide G protein regulated effector. Furthermore, our study finds that multiple mutants in Gα o associated with GNAO1 encephalopathy have defects in downstream effector interactions, which could underly some of the manifestations of this disease.","journal":"Journal of Biological Chemistry","year":2025,"id":526156,"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":3,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9586,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2025-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":504787,"name":"Naincy R. Chandan","orcid":"0000-0001-8097-1867","position":1,"is_corresponding":false},{"id":1401671,"name":"Beiyun Wang","orcid":null,"position":2,"is_corresponding":false},{"id":1401672,"name":"Elaine Qu","orcid":null,"position":3,"is_corresponding":false},{"id":336936,"name":"Alan V. Smrcka","orcid":"0000-0003-3099-8812","position":4,"is_corresponding":false},{"id":1401670,"name":"Nathalie Momplaisir","orcid":null,"position":0,"is_corresponding":true}],"reference_count":90,"raw_metadata":null,"created_at":"2026-07-19T02:50:25.860105Z","pmid":"40615045","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":[]}