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Updated: Aug 14, 2026
Imaging G Protein-coupled Receptor-mediated Chemotaxis and its Signaling Events in Neutrophil-like HL60 Cells
Published on: September 14, 2016
Characterization of transferrin receptor-dependent GaC-Tf-FeN transport in human leukemic HL60 cells
Ying-Qi Li1, Bin Liu, Chun-Gui Zhao
1Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Molecular Science, Shanxi University, Taiyuan, Shanxi 030006, China.
Background:
Understanding the uptake of GaC-Tf-FeN by cells will provide key insights into studies on transferrin-mediated drug delivery.
Methods:
The mechanism of GaC-Tf-FeN transporting into and out of HL60 cells has been investigated by comparing transports between GaC-Tf-FeN and apoTf by means of 125I-labeled transferrin.
Results:
An association constant for GaC-Tf-FeN was 2 times that for apoTf. GaC-Tf-FeN and apoTf of cell surface-bound displayed similar kinetics during the uptake, but the release rates of internalized GaC-Tf-FeN and apoTf from cells were different which showed characteristic disparate. The release continued to occur during the incubation of GaC-Tf-FeN in the presence of nonradioactive apoTf. Neither NaN3 nor NH4Cl could completely block internalization of GaC-Tf-FeN, but they prevented the release of GaC-Tf-FeN from the cells. Excess cold unlabeled apoTf could overcome the block in the release due to NH4Cl but not NaN3. The binding and internalization of GaC-Tf-FeN could be competitively inhibited by nonradioactive apoTf. It implies that both bind to the same receptor on the membrane and the localization of GaC-Tf-FeN resembles that of apoTf inside cells. Pretreated cells with pronase abolished the binding of GaC-Tf-FeN significantly.
Conclusion:
On the basis of these findings, we proposed the "transferrin receptor" for the mechanism of GaC-Tf-FeN transport by HL60 cells.
