Recruitment of epidermal growth factor and transferrin receptors into coated pits in vitro: Differing biochemical requirements

Christophe Lamaze, Takeshi Baba, Thomas E. Redelmeier, Sandra L. Schmid

Research output: Contribution to journalArticlepeer-review

55 Scopus citations

Abstract

The biochemical requirements for epidermal growth factor (EGF) and transferrin receptor-mediated endocytosis were compared using perforated human A431 cells. Morphological studies showed that horseradish peroxidase (HRP)-conjugated EGF and gold-labeled antitransferrin (Tfn) receptor antibodies were colocalized during endocytosis in vitro. The sequestration of both ligands into deeply invaginated coated pits required ATP hydrolysis and cytosolic factors and was inhibited by GTPγS, indicating mechanistic similarities. Importantly, several differences in the biochemical requirements for sequestration of EGF and Tfn were also detected. These included differing requirements for soluble AP (clathrin assembly protein) complexes, differing cytosolic requirements, and differing sensitivities to the tyrosine kinase inhibitor, genistein. The biochemical differences detected between EGF and Tfn sequestration most likely reflect specific requirements for the recruitment of EGF-receptors (R) into coated pits. This assay provides a novel means to identify the molecular bases for these biochemical distinctions and to elucidate the mechanisms involved in ligand-induced recruitment of EGF-R into coated pits.

Original languageEnglish (US)
Pages (from-to)715-727
Number of pages13
JournalMolecular biology of the cell
Volume4
Issue number7
StatePublished - 1993

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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