{"database":"biostudies-literature","file_versions":[],"scores":null,"additional":{"submitter":["Wang Y"],"funding":["NIGMS NIH HHS"],"pagination":["386-92"],"full_dataset_link":["https://www.ebi.ac.uk/biostudies/studies/S-EPMC3196267"],"repository":["biostudies-literature"],"omics_type":["Unknown"],"volume":["155(3)"],"pubmed_abstract":["A proinsulin-transferrin (ProINS-Tf) recombinant fusion protein was designed and characterized for the sustained release of an active form of insulin (INS) by hepatoma cells. During incubation with H4IIE hepatoma cells, a gradual decline of ProINS-Tf concentration, with a concomitant generation of the immuno-reactive insulin-transferrin (irINS-Tf), was detected in the culture medium by using INS- or proinsulin (ProINS)-specific radioimmunoassay (RIA) system. Further studies indicated that the conversion of ProINS-Tf to irINS-Tf was a transferrin receptor (TfR) mediated process that was pH-sensitive, and temperature- and microtubule-dependent. These results suggest that the conversion occurred during the slow recycling route of transferrin (Tf)-TfR pathway, possibly processed by proteases in the slow recycling compartments juxtaposed to the trans-Golgi network (TGN). ProINS-Tf exhibited little activity in the short-term promotion of glucose uptake in adipocytes, indicating that it was in an inactive form similar to ProINS. Stimulation of Akt phosphorylation by ProINS-Tf was detected only after prolonged incubation with H4IIE cells. On the other hand, ProINS-Tf pre-incubated with H4IIE cells for 24h acquired an immediate activity of stimulating Akt phosphorylation. Furthermore, ProINS-Tf elicited a strong activity in the inhibition of glucose production following 24h incubation with H4IIE cells. Based on these findings, we conclude that the Tf-TfR endocytosis and recycling pathway enables the conversion and release of ProINS-Tf in an active form of irINS-Tf. Results from this study suggest that the Tf-TfR pathway can be exploited for the design of prohormone-Tf fusion proteins as protein prodrugs for their sustained and targeted activation."],"journal":["Journal of controlled release : official journal of the Controlled Release Society"],"pubmed_title":["Receptor-mediated activation of a proinsulin-transferrin fusion protein in hepatoma cells."],"pmcid":["PMC3196267"],"funding_grant_id":["GM063647","R01 GM063647","R01 GM063647-08"],"pubmed_authors":["Shen WC","Chen YS","Wang Y","Zaro JL"],"additional_accession":[]},"is_claimable":false,"name":"Receptor-mediated activation of a proinsulin-transferrin fusion protein in hepatoma cells.","description":"A proinsulin-transferrin (ProINS-Tf) recombinant fusion protein was designed and characterized for the sustained release of an active form of insulin (INS) by hepatoma cells. During incubation with H4IIE hepatoma cells, a gradual decline of ProINS-Tf concentration, with a concomitant generation of the immuno-reactive insulin-transferrin (irINS-Tf), was detected in the culture medium by using INS- or proinsulin (ProINS)-specific radioimmunoassay (RIA) system. Further studies indicated that the conversion of ProINS-Tf to irINS-Tf was a transferrin receptor (TfR) mediated process that was pH-sensitive, and temperature- and microtubule-dependent. These results suggest that the conversion occurred during the slow recycling route of transferrin (Tf)-TfR pathway, possibly processed by proteases in the slow recycling compartments juxtaposed to the trans-Golgi network (TGN). ProINS-Tf exhibited little activity in the short-term promotion of glucose uptake in adipocytes, indicating that it was in an inactive form similar to ProINS. Stimulation of Akt phosphorylation by ProINS-Tf was detected only after prolonged incubation with H4IIE cells. On the other hand, ProINS-Tf pre-incubated with H4IIE cells for 24h acquired an immediate activity of stimulating Akt phosphorylation. Furthermore, ProINS-Tf elicited a strong activity in the inhibition of glucose production following 24h incubation with H4IIE cells. Based on these findings, we conclude that the Tf-TfR endocytosis and recycling pathway enables the conversion and release of ProINS-Tf in an active form of irINS-Tf. Results from this study suggest that the Tf-TfR pathway can be exploited for the design of prohormone-Tf fusion proteins as protein prodrugs for their sustained and targeted activation.","dates":{"release":"2011-01-01T00:00:00Z","publication":"2011 Nov","modification":"2024-11-09T04:24:10.021Z","creation":"2019-06-05T16:48:58Z"},"accession":"S-EPMC3196267","cross_references":{"pubmed":["21756950"],"doi":["10.1016/j.jconrel.2011.06.029"]}}