Faculty Collaboration Database

The cation-dependent mannose 6-phosphate receptor. Structural requirements for mannose 6-phosphate binding and oligomerization. J Biol Chem 1989 Jul 05;264(19):11458-67

Date

07/05/1989

Pubmed ID

2544594

Scopus ID

2-s2.0-0024356196 (requires institutional sign-in at Scopus site)   47 Citations

Abstract

The structural requirements for oligomerization and the generation of a functional mannose 6-phosphate (Man-6-P) binding site of the cation-dependent mannose 6-phosphate receptor (CD-MPR) were analyzed. Chemical cross-linking studies on affinity-purified CD-MPR and on solubilized membranes containing the receptor indicate that the CD-MPR exists as a homodimer. To determine whether dimer formation is necessary for the generation of a Man-6-P binding site, a cDNA coding for a truncated receptor consisting of only the signal sequence and the extracytoplasmic domain was constructed and expressed in Xenopus laevis oocytes. The expressed protein was completely soluble, monomeric in structure, and capable of binding phosphomannosyl residues. Like the dimeric native receptor, the truncated receptor can release its ligand at low pH. Ligand blot analysis using bovine testes beta-galactosidase showed that the monomeric form of the CD-MPR from bovine liver and testes is capable of binding Man-6-P. These results indicate that the extracytoplasmic domain of the receptor contains all the information necessary for ligand binding as well as for acid-dependent ligand dissociation and that oligomerization is not required for the formation of a functional Man-6-P binding site. Several different mutant CD-MPRs were generated and expressed in X. laevis oocytes to determine what region of the receptor is involved in oligomerization. Chemical cross-linking analyses of these mutant proteins indicate that the transmembrane domain is important for establishing the quaternary structure of the CD-MPR.

Author List

Dahms NM, Kornfeld S

Author

Nancy M. Dahms PhD Professor in the Biochemistry department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Amino Acid Sequence
Animals
Cations
Cattle
Cloning, Molecular
Cross-Linking Reagents
DNA
Female
Hexosephosphates
Hydrogen-Ion Concentration
Liver
Macromolecular Substances
Male
Mannosephosphates
Mice
Molecular Sequence Data
Mutation
Oocytes
Receptor, IGF Type 2
Receptors, Cell Surface
Structure-Activity Relationship
Testis
Transfection
Xenopus laevis