Faculty Collaboration Database

Characterization of mannose 6-phosphate receptors (MPRs) from opossum liver: opossum cation-independent MPR binds insulin-like growth factor-II. Endocrinology 1993 Aug;133(2):440-6

Date

08/01/1993

Pubmed ID

8344189

DOI

10.1210/endo.133.2.8344189

Scopus ID

2-s2.0-0027317013 (requires institutional sign-in at Scopus site)   36 Citations

Abstract

Bovine, human, and rat cation-independent mannose 6-phosphate receptors (CI-MPRs) are capable of binding both mannose 6-phosphate and insulin-like growth factor-II (IGF-II). However, the receptor isolated from either chicken or frog lacks the high affinity IGF-II-binding site. To determine whether CI-MPRs isolated from a species that is closely related to placental mammals can bind IGF-II, the MPRs were purified from a marsupial, the American opossum (Didelphis virginiana), by phosphomannan-Sepharose affinity chromatography and then tested for their ability to bind IGF-II. Opossum liver expressed both the CI-MPR and the cation-dependent MPR (CD-MPR). Both receptors contained Asn-linked oligosaccharides. In contrast to CD-MPRs isolated from other species, the opossum CD-MPR displayed heterogeneity with respect to the number of Asn-linked oligosaccharide chains it contains. The CI-MPR isolated from opossum liver, like the CI-MPR from bovine liver, bound iodinated human recombinant IGF-II. However, Scatchard analysis revealed that the opossum CI-MPR bound IGF-II with a lower affinity (Kd = 14.5 nM) than the bovine receptor (Kd = 0.2 nM). The addition of excess IGF-II, but not IGF-I or insulin, inhibited binding to [125I]IGF-II, indicating that the opossum CI-MPR exhibits specificity for IGF-II. These results suggest that the emergence of a high affinity IGF-II-binding site in the CI-MPR occurred in evolution before the divergence of marsupials and placental mammals from their last common ancestor.

Author List

Dahms NM, Brzycki-Wessell MA, Ramanujam KS, Seetharam B

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

Animals
Asparagine
Binding Sites
Cations
Cattle
Chromatography, Affinity
Humans
Immunosorbent Techniques
Insulin-Like Growth Factor II
Iodine Radioisotopes
Liver
Oligosaccharides
Opossums
Receptor, IGF Type 2
Recombinant Proteins