title: The membrane-anchoring domain of epidermal growth factor receptor ligands dictates their ability to operate in juxtacrine mode.
abstract: All ligands of the epidermal growth factor (EGF) receptor (EGFR) are synthesized as membrane-anchored precursors. Previous work has suggested that some ligands, such as EGF, must be proteolytically released to be active, whereas others, such as heparin-binding EGF-like growth factor (HB-EGF) can function while still anchored to the membrane (i.e., juxtacrine signaling). To explore the structural basis for these differences in ligand activity, we engineered a series of membrane-anchored ligands in which the core, receptor-binding domain of EGF was combined with different domains of both EGF and HB-EGF. We found that ligands having the N-terminal extension of EGF could not bind to the EGFR, even when released from the membrane. Ligands lacking an N-terminal extension, but possessing the membrane-anchoring domain of EGF, still required proteolytic release for activity, whereas ligands with the membrane-anchoring domain of HB-EGF could elicit full biological activity while still membrane anchored. Ligands containing the HB-EGF membrane anchor, but lacking an N-terminal extension, activated EGFR during their transit through the Golgi apparatus. However, cell-mixing experiments and fluorescence resonance energy transfer studies showed that juxtacrine signaling typically occurred in trans at the cell surface, at points of cell-cell contact. Our data suggest that the membrane-anchoring domain of ligands selectively controls their ability to participate in juxtacrine signaling and thus, only a subclass of EGFR ligands can act in a juxtacrine mode.
authors.affiliation: Department of Pathology, Division of Cell Biology and Immunology, University of Utah, Salt Lake City, UT 84133, USA.
authors.forename: Jianying
authors.initials: J
authors.lastname: Dong
authors.forename: Lee K
authors.initials: LK
authors.lastname: Opresko
authors.forename: William
authors.initials: W
authors.lastname: Chrisler
authors.forename: Galya
authors.initials: G
authors.lastname: Orr
authors.forename: Ryan D
authors.initials: RD
authors.lastname: Quesenberry
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Lauffenburger
authors.forename: H Steven
authors.initials: HS
authors.lastname: Wiley
mesh_terms: D000818:Animals; D016466:CHO Cells; D002450:Cell Communication; D002460:Cell Line; D049109:Cell Proliferation; D006224:Cricetinae; D003412:Cricetulus; D004815:Epidermal Growth Factor / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D066246:ErbB Receptors / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D031541:Fluorescence Resonance Energy Transfer; D019084:Fluorescent Antibody Technique, Indirect; D006056:Golgi Apparatus / Q000378:metabolism; D066257:Heparin-binding EGF-like Growth Factor; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D008024:Ligands; D051379:Mice; D018613:Microscopy, Confocal; D011233:Precipitin Tests; D017434:Protein Structure, Tertiary; D015398:Signal Transduction
chemical_list: C587883:HBEGF protein, human; C587884:Hbegf protein, mouse; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D008024:Ligands; D004815:Epidermal Growth Factor; D066246:ErbB Receptors