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Structural model of phospholipid-reconstituted human transferrin receptor derived by electron microscopy
1Institut für Laboratoriumsmedizin und Pathobiochemie Charité Campus Virchow-Klinikum Augustenburger Platz 1, D-13353, Berlin, Germany.
Structure (London, England : 1993)
|October 22, 1998
Summary
Researchers developed the first molecular model of the transferrin receptor (TfR) using cryo-electron microscopy. This reveals the TfR dimer
Area of Science:
- Structural biology
- Cell biology
- Biophysics
Background:
- The transferrin receptor (TfR) is crucial for cellular iron uptake.
- Previous studies lacked detailed molecular dimensions of the TfR.
- TfR serves as a model for endocytosis receptors.
Purpose of the Study:
- To derive the first molecular model of the human transferrin receptor (TfR).
- To elucidate the structural dimensions and organization of TfR.
Main Methods:
- High-resolution cryo-electron microscopy of purified, lipid-reconstituted human TfR.
- Scanning transmission electron microscopy.
- Comparative protein sequence analysis.
Main Results:
- A structural model of the TfR dimer was derived, showing a globular extracellular domain and a 2.9 nm stalk.
- Reconstituted TfR formed proteoparticles (rosette-like structures) with a diameter of 31.5 nm and mass of 1669 kDa.
- Proteoparticles comprised nine TfR dimers, with each dimer averaging 186 kDa.
Conclusions:
- Proteoparticles resemble TfR exosomes, suggesting TfR self-association potential.
- This self-association may aid endosomal sequestration and recycling of TfR.
- The TfR stalk likely facilitates packing in cellular structures like coated pits.