Transport of the recycling marker transferrin was analysed in polarized hepatic HepG2 cells using quantitative fluorescence microscopy and mathematical modelling. A detailed map and kinetic model for transport of transferrin in hepatic cells was developed. Fluorescent transferrin was found to be transported sequentially through basolateral SE (sorting endosomes) to a SAC/ARC (subapical compartment/apical recycling compartment). DiI (di-indocarbocyanine) lipid probes of different acyl chain length (DiIC12 and DiIC16) co-localized with transferrin in basolateral SE and in the SAC/ARC. By kinetic comparison of hepatic transport of transferrin and labelled HDL (high-density lipoprotein), it is shown that transport of transferrin from SE to the SAC/ARC follows a default pathway together with HDL. Kinetic modelling of fluorescence data provides an identical half-time for SE-to-SAC/ARC transport of transferrin and fluorescent HDL (t½=4.2 min). Fluorescent transferrin was found to recycle with a half-time of t½=12.9 min from the SAC/ARC to the basolateral cell surface of HepG2 cells. In contrast with HDL, targeting of labelled transferrin from the SAC/ARC to the apical biliary canaliculus was negligible. The results indicate that transport from basolateral hepatic SE to the SAC/ARC represents a bulk flow process and that polarized sorting occurs mainly at the level of the SAC/ARC.
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Research Article|
November 14 2006
Quantification of polarized trafficking of transferrin and comparison with bulk membrane transport in hepatic cells
Daniel Wüstner
Daniel Wüstner
1
1Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
1To whom correspondence should be addressed (email wuestner@bmb.sdu.dk).
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Publisher: Portland Press Ltd
Received:
April 27 2006
Revision Received:
July 06 2006
Accepted:
July 31 2006
Accepted Manuscript online:
July 31 2006
Online ISSN: 1470-8728
Print ISSN: 0264-6021
The Biochemical Society, London
2006
Biochem J (2006) 400 (2): 267–280.
Article history
Received:
April 27 2006
Revision Received:
July 06 2006
Accepted:
July 31 2006
Accepted Manuscript online:
July 31 2006
Citation
Daniel Wüstner; Quantification of polarized trafficking of transferrin and comparison with bulk membrane transport in hepatic cells. Biochem J 1 December 2006; 400 (2): 267–280. doi: https://doi.org/10.1042/BJ20060626
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