Title: Proper sorting of the cation-dependent mannose 6-phosphate receptor in endosomes depends on a pair of aromatic amino acids in its cytoplasmic tail
Authors : Schweizer, Anja
Kornfeld, Stuart
Rohrer, Jack
Published in : Proceedings of the National Academy of Sciences
Volume(Issue) : 94
Issue : 26
Pages : 14471
Pages to: 14476
Publisher / Ed. Institution : National Academy of Sciences
Issue Date: 23-Dec-1997
License (according to publishing contract) : Licence according to publishing contract
Type of review: Peer review (Publication)
Language : English
Subject (DDC) : 571: Physiology and related subjects
572: Biochemistry
Abstract: The 67-amino acid cytoplasmic tail of the cation-dependent mannose 6-phosphate receptor (CD-MPR) contains a signal(s) that prevents the receptor from entering lysosomes where it would be degraded. To identify the key residues required for proper endosomal sorting, we analyzed the intracellular distribution of mutant forms of the receptor by Percoll density gradients. A receptor with a Trp19 --> Ala substitution in the cytoplasmic tail was highly missorted to lysosomes whereas receptors with either Phe18 --> Ala or Phe13 --> Ala mutations were partially defective in avoiding transport to lysosomes. Analysis of double and triple mutants confirmed the key role of Trp19 for sorting of the CD-MPR in endosomes, with Phe18, Phe13, and several neighboring residues contributing to this function. The addition of the Phe18-Trp19 motif of the CD-MPR to the cytoplasmic tail of the lysosomal membrane protein Lamp1 was sufficient to partially impair its delivery to lysosomes. Replacing Phe18 and Trp19 with other aromatic amino acids did not impair endosomal sorting of the CD-MPR, indicating that two aromatic residues located at these positions are sufficient to prevent the receptor from trafficking to lysosomes. However, alterations in the spacing of the diaromatic amino acid sequence relative to the transmembrane domain resulted in receptor accumulation in lysosomes. These findings indicate that the endosomal sorting of the CD-MPR depends on the correct presentation of a diaromatic amino acid-containing motif in its cytoplasmic tail. Because a diaromatic amino acid sequence is also present in the cytoplasmic tail of other receptors known to be internalized from the plasma membrane, this feature may prove to be a general determinant for endosomal sorting.
Departement: Life Sciences und Facility Management
Publication type: Article in scientific Journal
DOI : 10.1073/pnas.94.26.14471
ISSN: 0027-8424
URI: https://digitalcollection.zhaw.ch/handle/11475/6814
Appears in Collections:Publikationen Life Sciences und Facility Management

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