Partition of epidermal growth factor receptors on freeze-fractured plasma membranes of A431 cells is affected by the ligand

L. V. Lotti, A. Pavan, C. Zompetta, P. Mancini, A. Faggioni, L. Frati, M. R. Torrisi

Research output: Contribution to journalArticlepeer-review

Abstract

The fracture immunolabel technique, which permits assessment of the partition of transmembrane proteins with the inner or outer leaflets of the freeze-fractured membrane, was used to analyze the behavior on fracture of epidermal growth factor (EGF) receptors over the plasma membranes of A431 cells. The receptors partition mainly with the outer leaflet of the freeze-fractured plasma membranes, whereas they become associated with the inner leaflet when they are occupied by the ligand. This modified partition is even more evident after receptor clustering induced by incubation with EGF at 37°C. Treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA) decreases the number of receptors over both inner and outer leaflets. An effect similar to that induced by the ligand is obtained when receptor aggregation is achieved using anti-receptor monoclonal antibodies (MAb). The modified partition therefore indicates receptor activation and appears to be a consequence of receptor cross-linking rather than to reflect a conformational change of the receptor molecule. Parallel immunolabeling with anti-phosphotyrosine antibodies of freeze-fractured EGF-treated A431 cells reveals that the receptors, when activated, are associated only with the inner leaflet of the plasma membrane.

Original languageEnglish
Pages (from-to)1227-1235
Number of pages9
JournalJournal of Histochemistry and Cytochemistry
Volume39
Issue number9
Publication statusPublished - 1991

Keywords

  • Epidermal growth factor receptor
  • Freeze-fracture
  • Membrane

ASJC Scopus subject areas

  • Anatomy
  • Cell Biology

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