{"doi":"10.17615/fe9a-m083","title":"Platelet-derived growth factor (PDGF) alpha receptor activation modulates the calcium mobilizing activity of the PDGF beta receptor in Balb/c3T3 fibroblasts.","abstract":"In order to determine whether distinct platelet-derived growth factor (PDGF) receptors (alpha and beta) can modulate the activity of one another, PDGF isoform (AA, BB, and AB)-stimulated changes in Ca2+i were monitored by digitized video microscopy in single cells upon sequential addition of PDGF isoforms. In Balb/c 3T3 fibroblasts, all PDGF isoforms were capable of stimulating increases in Ca2+i of 200-600% above basal levels, although with different potencies: BB greater than or equal to AB greater than AA. All cells were BB-PDGF-responsive, but only 74% of cells examined responded to AA-PDGF. The Ca2+i response elicited by BB-PDGF was inhibited by 60-75% in cells stimulated 10 min earlier with the AA isoform. The half-life of this inhibition was 22 min. In cells in which the alpha receptor was down-regulated by prolonged incubation with AA-PDGF, BB-induced Ca2+i responses were not inhibited. Pretreatment of cells with phorbol ester did not inhibit BB-PDGF-induced increases in Ca2+i, yet down-regulation of PKC activity prevented the AA-PDGF inhibition of BB-PDGF-induced Ca2+i responses. An increase in Ca2+i induced by AlF(4-)-stimulated IP3 generation did not inhibit a subsequent BB-PDGF Ca2+i response; however, attenuation of AA-PDGF-induced extracellular Ca2+ influx with EGTA prevented the inhibition of BB-PDGF-induced Ca2+i increases. Readdition of Ca2+ to the medium after removal of EGTA restored the inhibition of the BB-PDGF Ca2+i response. The inhibition of the BB-PDGF Ca2+i response by AA-PDGF was not caused by inhibition of PDGF receptor tyrosine autophosphorylation, which was unchanged after pretreatment with AA-PDGF. These results demonstrate: (a) that only a subpopulation of cells possess a functional alpha receptor-mediated response as assessed by AA-PDGF-induced increases in Ca2+i, whereas all cells possess the beta receptor-mediated responses; and (b) AA-PDGF and its associated alpha receptor can modulate the activity of the beta receptor through a mechanism that is dependent upon Ca(2+)-influx which may be controlled in part by PKC activation.","journal":"UNC Libraries","year":2021,"id":212628,"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":1,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9559,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2021-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":540194,"name":"Gerald W. Gordon","orcid":null,"position":1,"is_corresponding":false},{"id":304429,"name":"H. Shelton Earp","orcid":"0000-0003-1229-4619","position":2,"is_corresponding":false},{"id":166229,"name":"Brian Herman","orcid":null,"position":3,"is_corresponding":false},{"id":803593,"name":"Pamela A Diliberto","orcid":null,"position":4,"is_corresponding":false},{"id":803592,"name":"Chun Li Yu","orcid":null,"position":0,"is_corresponding":true}],"reference_count":0,"raw_metadata":null,"created_at":"2026-07-18T23:52:27.434608Z","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":[]}