caa a22 4500 477081746 CHVBK 20180405111451.0 cr unu---uuuuu 170330e19960901xx s 000 0 eng 10.1007/BF02723052 doi (NATIONALLICENCE)springer-10.1007/BF02723052 Intermediate steps in cellular iron uptake from transferrin. II. A cytoplasmic pool of iron is released from cultured cells via temperature-dependent mechanical wounding [Elektronische Daten] [D. Richardson, L. Dickson, E. Baker] Summary: A previous study described a cytoplasmic, transferrin (Tf)-free, iron (Fe) pool that was detected only when cells were mechanically detached from the culture substratum at 4°C, after initial incubation with59Fe-125I-Tf at 37°C (Richardson and Baker, 1992a). The release of this internalized59Fe could be markedly reduced if the cells were treated with proteases or incubated at 37°C prior to detachment. The present study was designed to characterize this Fe pool and understand the mechanism of its release. The results show that cellular59Fe release increased linearly as a function of preincubation time with59Fe-Tf subsequent to mechanical detachment at 4°C using a spatula. These data suggest that the59Fe released was largely composed of end product(s) and was not an "intermediate Fe pool.” When the Fe(II) chelator, dipyridyl (DP), was incubated with59Fe-Tf and the cells, it prevented the accumulation of59Fe that was released following mechanical detachment at 4°C. Other chelators had much less effect on the proportion of59Fe released. Examination of the59Fe released showed that after a 4-h preincubation with59Fe-Tf, approximately 50% of the59Fe was present in ferritin. These data indicate that mechanical detachment of cells at 4°C resulted in membrane disruptions that allow the release of high M, molecules. Moreover, electron microscopy studies showed that detachment of cells from the substratum at 4°C resulted in pronounced membrane damage. In contrast, when cells were detached at 37°C, or at 4°C after treatment with pronase, membrane damage was minimal or not apparent. These results may imply that temperature-dependent processes prevent the release of intracellular contents on membrane wounding, or alternatively, prevent wounding at 37°C. The evidence also indicates that caution is required when interpreting data from expriments where cells have been mechanically detached at 4°C. Society for in Vitro Biology, 1996 mechanical wounding nationallicence intracellular iron pools nationallicence ferritin nationallicence transferrin nationallicence Richardson D. Lady Davis Institute for Medical Research of the Sir Mortimer B. Davis-Jewish General Hospital, 3755 Chemin de la Cote-Ste-Catherine, H3T 1E2, Montréal, Québec, Canada aut Dickson L. Department of Physiology, University of Western Australia, 6009, Perth, Western Australia aut Baker E. Department of Physiology, University of Western Australia, 6009, Perth, Western Australia aut In Vitro Cellular & Developmental Biology - Animal Springer-Verlag 32/8(1996-09-01), 486-495 1071-2690 32:8<486 1996 32 11626 https://doi.org/10.1007/BF02723052 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02723052 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Richardson D. Lady Davis Institute for Medical Research of the Sir Mortimer B. Davis-Jewish General Hospital, 3755 Chemin de la Cote-Ste-Catherine, H3T 1E2, Montréal, Québec, Canada aut NATIONALLICENCE 700 1- Dickson L. Department of Physiology, University of Western Australia, 6009, Perth, Western Australia aut NATIONALLICENCE 700 1- Baker E. Department of Physiology, University of Western Australia, 6009, Perth, Western Australia aut NATIONALLICENCE 773 0- In Vitro Cellular & Developmental Biology - Animal Springer-Verlag 32/8(1996-09-01), 486-495 1071-2690 32:8<486 1996 32 11626 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer