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Truncated forms of the insulin-like growth factor II (IGF-II)/mannose 6-phosphate receptor encompassing the IGF-II binding site: characterization of a point mutation that abolishes IGF-II binding.

Publication ,  Journal Article
Garmroudi, F; Devi, G; Slentz, DH; Schaffer, BS; MacDonald, RG
Published in: Mol Endocrinol
June 1996

Complete understanding of the functional significance of insulin-like growth factor II (IGF-II) binding by the IGF-II/mannose-6-phosphate (Man-6-P) receptor requires mapping and ultimately mutational analysis of the receptor's IGF-II binding domain. Recent advances have localized the IGF-II binding site to extracytoplasmic repeats 10-11. To improve resolution of the binding site map, a nested set of epitope-tagged, truncated forms of the human IGF-II/Man-6-P receptor were transiently expressed in COS-7 cells. The IGF-II binding properties of truncated receptors immunoprecipitated from cell lysates and conditioned media were determined by affinity cross-linking. From the largest truncated receptor, encompassing extracytoplasmic repeats 8-11 (M(r) 68 K), through the smallest, comprised primarily of repeat 11 (M(r) 23 K), all were able to bind and cross-link to IGF-II. As a group, the truncated receptors had similar affinities for IGF-II, but with relative binding affinities 5-to 10-fold lower than those of full-length receptors. A point mutation substituting threonine for isoleucine at residue 1572, located in the NH2-terminal half of repeat 11, completely abolished IGF-II binding. We conclude that repeat 11 of the IGF-II/Man-6-P receptor's extracytoplasmic domain contains the minimal elements required for binding and cross-linking to IGF-II, and that lle1572 and other residues within the NH2-terminal half of repeat 11 are particularly important for IGF-II interaction.

Duke Scholars

Published In

Mol Endocrinol

DOI

ISSN

0888-8809

Publication Date

June 1996

Volume

10

Issue

6

Start / End Page

642 / 651

Location

United States

Related Subject Headings

  • Substrate Specificity
  • Repetitive Sequences, Nucleic Acid
  • Recombinant Proteins
  • Receptor, IGF Type 2
  • Precipitin Tests
  • Mutation
  • Iodine Radioisotopes
  • Insulin-Like Growth Factor II
  • Humans
  • Endocrinology & Metabolism
 

Citation

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Garmroudi, F., Devi, G., Slentz, D. H., Schaffer, B. S., & MacDonald, R. G. (1996). Truncated forms of the insulin-like growth factor II (IGF-II)/mannose 6-phosphate receptor encompassing the IGF-II binding site: characterization of a point mutation that abolishes IGF-II binding. Mol Endocrinol, 10(6), 642–651. https://doi.org/10.1210/mend.10.6.8776724
Garmroudi, F., G. Devi, D. H. Slentz, B. S. Schaffer, and R. G. MacDonald. “Truncated forms of the insulin-like growth factor II (IGF-II)/mannose 6-phosphate receptor encompassing the IGF-II binding site: characterization of a point mutation that abolishes IGF-II binding.Mol Endocrinol 10, no. 6 (June 1996): 642–51. https://doi.org/10.1210/mend.10.6.8776724.

Published In

Mol Endocrinol

DOI

ISSN

0888-8809

Publication Date

June 1996

Volume

10

Issue

6

Start / End Page

642 / 651

Location

United States

Related Subject Headings

  • Substrate Specificity
  • Repetitive Sequences, Nucleic Acid
  • Recombinant Proteins
  • Receptor, IGF Type 2
  • Precipitin Tests
  • Mutation
  • Iodine Radioisotopes
  • Insulin-Like Growth Factor II
  • Humans
  • Endocrinology & Metabolism