UNIGE document Scientific Article
previous document  unige:11503  next document
add to browser collection

Clathrin-coated pit-mediated receptor internalization. Role of internalization signals and receptor mobility

Johansson, B.
Magnusson, K. E.
Carpentier, J. L.
Published in Journal of Biological Chemistry. 1993, vol. 268, no. 31, p. 23191-23196
Abstract Most signals controlling receptor-mediated endocytosis have been identified by alteration of sequences present in receptors normally internalized via clathrin-coated pits. In the present work we have reconsidered the factors that control internalization the other way around: i.e. by introducing potential internalization sequences in complement receptor 1 (CR1) which does not preferentially associate with clathrin-coated pits. The analysis of the internalization efficiency of NPxY related motifs generated by substituting His2010 and/or Glu2015 by either Phe or Tyr indicates that FxNPxY is the stronger promoter of endocytosis and that the signal efficiency depends on the presence of aromatic residues (including a tyrosine) at both ends of the -xNPx- motif. Moreover, CR1-tyr (substitution of Glu2015 for Tyr) internalization was superposable to that of a receptor composed of the extracellular and transmembrane domains of CR1 fused to the intracytoplasmic tail of the low density lipoprotein (LDL) receptor (including the FxNPxY motif) (CR1-LDL). When analyzed by fluorescence recovery after photobleaching, the surface mobility of CR1-LDL was decreased as compared with that of either CR1-tyr or CR1-wt, despite a similar association with clathrin-coated pits. The role of receptor mobility in internalization was confirmed by the observation that CR1-tl, with a deletion of the cytoplasmic tail, was more mobile and more efficiently internalized than CR1-wt.
Keywords Amino Acid SequenceBase SequenceCoated Pits, Cell-Membrane/ physiologyDNA Primers/chemistryEndocytosisHumansMembrane FluidityMolecular Sequence DataMutagenesis, Site-DirectedReceptors, Complement 3b/ metabolismSequence AlignmentSequence Homology, Amino AcidStructure-Activity Relationship
Stable URL http://archive-ouverte.unige.ch/unige:11503
Full text
Article - document accessible for UNIGE members only Limited access to UNIGE
Other version: http://www.jbc.org/content/268/31/23191.full.pdf
PMID: 8226838
144 hits and 0 download since 2010-08-27
Export document
Format :
Citation style :