Dominant-negative effect of truncated mannose 6-phosphate/insulin-like growth factor II receptor species in cancer

Jodi L. Kreiling, Michelle A. Montgomery, Joseph R. Wheeler, Jennifer L. Kopanic, Christopher M. Connelly, Megan E. Zavorka, Jenna L. Allison, Richard G. MacDonald

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

Oligomerization of the mannose 6-phosphate/insulin-like growth factor II receptor (M6P/IGF2R) is important for optimal ligand binding and internalization. M6P/IGF2R is a tumor suppressor gene that exhibits loss of heterozygosity and is mutated in several cancers. We tested the potential dominant-negative effects of two cancer-associated mutations that truncate M6P/IGF2R in ectodomain repeats 9 and 14. Our hypothesis was that co-expression of the truncated receptors with the wild-type/endogenous full-length M6P/IGF2R would interfere with M6P/IGF2R function by heterodimer interference. Immunoprecipitation confirmed formation of heterodimeric complexes between full-length M6P/IGF2Rs and the truncated receptors, termed Rep9F and Rep14F. Remarkably, increasing expression of either Rep9F or Rep14F provoked decreased levels of full-length M6P/IGF2Rs in both cell lysates and plasma membranes, indicating a dominant-negative effect on receptor availability. Loss of full-length M6P/IGF2R was not due to increased proteasomal or lysosomal degradation, but instead arose from increased proteolytic cleavage of cell-surface M6P/IGF2Rs, resulting in ectodomain release, by a mechanism that was inhibited by metal ion chelators. These data suggest that M6P/IGF2R truncation mutants may contribute to the cancer phenotype by decreasing the availability of full-length M6P/IGF2Rs to perform tumor-suppressive functions such as binding/internalization of receptor ligands such as insulin-like growth factor II. Structured digital abstract with by (View Interaction:,) with by (View Interaction:,) Oligomerization of the mannose 6-phosphate/insulin-like growth factor II receptor (M6P/IGF2R) is important for optimal IGF-II binding, internalization, and degradation. Increasing expression of Rep9F or Rep14F, two cancer-associated M6P/IGF2R mutations that truncate the receptor in ectodomain repeats 9 and 14 decreased levels of full-length M6P/IGF2Rs. The effect was due to proteolytic cleavage resulting in ectodomain release and was inhibited by zinc chelators

Original languageEnglish (US)
Pages (from-to)2695-2713
Number of pages19
JournalFEBS Journal
Volume279
Issue number15
DOIs
StatePublished - Aug 2012

Keywords

  • dimerization
  • dominant negative
  • ectodomain shedding
  • mannose 6-phosphate receptor
  • truncation mutants

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Fingerprint

Dive into the research topics of 'Dominant-negative effect of truncated mannose 6-phosphate/insulin-like growth factor II receptor species in cancer'. Together they form a unique fingerprint.

Cite this