{"doi":"10.1042/bj2540343","title":"Two dephosphorylation pathways of inositol 1,4,5-trisphosphate in homogenates of the cellular slime mould <i>Dictyostelium discoideum</i>","abstract":"<jats:p>Dictyostelium discoideum homogenates contain phosphatase activity which rapidly dephosphorylates Ins(1,4,5)P3 (D-myo-inositol 1,4,5-trisphosphate) to Ins (myo-inositol). When assayed in Mg2+, Ins(1,4,5)P3 is dephosphorylated by the soluble Dictyostelium cell fraction to 20% Ins(1,4)P2 (D-myo-inositol 1,4-bisphosphate) and 80% Ins(4,5)P2 (D-myo-inositol 4,5-bisphosphate). In the particulate fraction Ins(1,4,5)P3 5-phosphatase is relatively more active than the Ins(1,4,5)P3 1-phosphatase. CaCl2 can replace MgCl2 only for the Ins(1,4,5)P3 5-phosphatase activity. Ins(1,4)P2 and Ins(4,5)P2 are both further dephosphorylated to Ins4P (D-myo-inositol 4-monophosphate), and ultimately to Ins. Li+ ions inhibit Ins(1,4,5)P3 1-phosphatase, Ins(1,4)P2 1-phosphatase, Ins4P phosphatase and L-Ins1P (L-myo-inositol 1-monophosphate) phosphatase activities; Ins(1,4,5)P3 1-phosphatase is 10-fold more sensitive to Li+ (half-maximal inhibition at about 0.25 mM) than are the other phosphatases (half-maximal inhibition at about 2.5 mM). Ins(1,4,5)P3 5-phosphatase activity is potently inhibited by 2,3-bisphosphoglycerate (half-maximal inhibition at 3 microM). Furthermore, 2,3-bisphosphoglycerate also inhibits dephosphorylation of Ins(4,5)P2. These characteristics point to a number of similarities between Dictyostelium phospho-inositol phosphatases and those from higher organisms. The presence of an hitherto undescribed Ins(1,4,5)P3 1-phosphatase, however, causes the formation of a different inositol bisphosphatase isomer [Ins(4,5)P2] from that found in higher organisms [Ins(1,4)P2]. The high sensitivity of some of these phosphatases for Li+ suggests that they may be the targets for Li+ during the alteration of cell pattern by Li+ in Dictyostelium.</jats:p>","journal":"Biochemical Journal","year":1988,"id":38694,"datarank":3.2274896280977083,"base_score":4.2626798770413155,"endowment":4.2626798770413155,"self_citation_contribution":0.6394019815561974,"citation_network_contribution":2.588087646541511,"self_endowment_contribution":0.6394019815561974,"citer_contribution":2.588087646541511,"corpus_percentile":null,"corpus_rank":null,"citation_count":70,"citer_count":51,"citers_with_citation_signal":42,"citers_with_endowment":42,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":191565,"name":"C Erneux","orcid":null,"position":1,"is_corresponding":false},{"id":191566,"name":"R Van Eijk","orcid":null,"position":2,"is_corresponding":false},{"id":191567,"name":"P J M Van Haastert","orcid":null,"position":3,"is_corresponding":false},{"id":191564,"name":"M M Van Lookeren Campagne","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"base_score":4.2626798770413155,"endowment":4.2626798770413155,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"2845948","pmcid":"PMC1135083","openalex_id":"https://openalex.org/W1552337332","authors":[],"funders":[],"total_grants":0,"fwci":4.6573,"citation_percentile":0.95543696,"influential_citations":1,"citation_trend":[{"year":2012,"count":1},{"year":2016,"count":1},{"year":2019,"count":1}],"oa_status":"bronze","license":null,"oa_locations":[{"url":"https://portlandpress.com/biochemj/article-pdf/254/2/343/628041/bj2540343.pdf","host_type":"journal"},{"url":"https://europepmc.org/articles/pmc1135083?pdf=render","host_type":"GREEN"},{"url":"https://portlandpress.com/biochemj/article-pdf/254/2/343/628041/bj2540343.pdf","host_type":"publisher"},{"url":"https://doi.org/10.1042/bj2540343","host_type":"journal"},{"url":"https://pubmed.ncbi.nlm.nih.gov/2845948","host_type":"repository"},{"url":"https://www.ncbi.nlm.nih.gov/pmc/articles/1135083","host_type":"repository"}],"fields_of_study":["Cellular Mechanics and Interactions","thermodynamics and calorimetric analyses","Microtubule and mitosis dynamics","Biology","Medicine","Chemistry","2,3-Diphosphoglycerate","Cell Fractionation","Chromatography, High Pressure Liquid","Dictyostelium","Diphosphoglyceric Acids","Hydrolysis","Inositol 1,4,5-Trisphosphate","Inositol Phosphates","Lithium","Phosphoric Monoester Hydrolases","Sugar Phosphates"],"mesh_terms":["Cell Fractionation","Chromatography, High Pressure Liquid","Dictyostelium","Diphosphoglyceric Acids","Hydrolysis","Inositol Phosphates","Lithium","Phosphoric Monoester Hydrolases","Sugar Phosphates","Inositol 1,4,5-Trisphosphate","2,3-Diphosphoglycerate"],"keywords":["Dephosphorylation","Inositol","Dictyostelium discoideum","Phosphatase","Dictyostelium","Biochemistry","Phosphorylation","Inositol phosphate","Biology","Alkaline phosphatase","Chemistry","Enzyme","Receptor","Gene"],"sdg_mappings":[],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[],"source":"live","citation_network_status":"fetched"},"created_at":"2026-06-11T05:19:38.244090Z","pmid":null,"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":[]}