Single-transmembrane domain IGF-II/M6P receptor: Potential interaction with g protein and its association with cholesterol-rich membrane domains

Asha Amritraj, Elena I. Posse De Chaves, Cheryl Hawkes, Richard G. MacDonald, Satyabrata Kar

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


The IGF-II/mannose 6-phosphate (M6P) receptor is a single-transmembrane domain glycoprotein that plays an important role in the intracellular trafficking of lysosomal enzymes and endocytosis-mediated degradation of IGF-II. The receptor may also mediate certain biological effects in response to IGF-II binding by interacting with G proteins. However, the nature of the IGF-II/M6P receptor's interaction with the G protein or with G protein-coupled receptor (GPCR) interacting proteins such as β-arrestin remains unclear. Here we report that [125I]IGF-II receptor binding in the rat hippocampal formation is sensitive to guanosine-5′-[γ-thio]triphosphate, mastoparan, and Mas-7, which are known to interfere with the coupling of the classical GPCR with G protein. Monovalent and divalent cations also influenced [125I]IGF-II receptor binding. The IGF-II/M6P receptor, as observed for several GPCRs, was found to be associated with β-arrestin 2, which exhibits sustained ubiquitination after stimulation with Leu27IGF-II, an IGF-II analog that binds rather selectively to the IGF-II/M6P receptor. Activation of the receptor by Leu27IGF-II induced stimulation of extracellular signal-related kinase 1/2 via a pertussis toxin-dependent pathway. Additionally, we have shown that IGF-II/M6P receptors under normal conditions are associated mostly with detergent- resistant membrane domains, but after stimulation with Leu27IGF-II, are translocated to the detergent-soluble fraction along with a portion of β-arrestin 2. Collectively these results suggest that the IGF-II/M6P receptor may interact either directly or indirectly with G protein as well as β-arrestin 2, and activation of the receptor by an agonist can lead to alteration in its subcellular distribution along with stimulation of an intracellular signaling cascade.

Original languageEnglish (US)
Pages (from-to)4784-4798
Number of pages15
Issue number10
StatePublished - Oct 1 2012

ASJC Scopus subject areas

  • Endocrinology


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