Abstract
The insulin-like growth factor-II/mannose 6-phosphate receptor (IGF-II/man6PR) can directly interact with and activate Gi-2, a GTP binding protein (G protein). We found that the segment of residues 2410-2423 in the human IGF-II/man6PR activates Gi-2 in a manner similar to G-coupled receptors. We observed a hierarchy of the segment action when tested on various G proteins, with an order of Gi-2 greater than Gi-1 approximately Gi-3 greater than Go. The segment had no effect on Gs or low molecular weight G proteins. The segment action depended on its primary structure and was potentiated when the segment was connected with a part of the receptor transmembrane region. Finally, the Gi-2-activating function of the human IGF-II/man6PR could be blocked by an antibody against the segment, indicating a critical role for this small region of the receptor.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Cattle
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Cytoplasm
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GTP-Binding Proteins / physiology*
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Guanosine 5'-O-(3-Thiotriphosphate)
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Guanosine Diphosphate / metabolism
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Guanosine Triphosphate / analogs & derivatives
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Guanosine Triphosphate / metabolism
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Immunologic Techniques
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In Vitro Techniques
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Magnesium / pharmacology
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Mannosephosphates
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Molecular Sequence Data
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Peptide Fragments / metabolism
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Phospholipids / pharmacology
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Receptor, IGF Type 2
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Receptors, Cell Surface / physiology*
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Receptors, Somatomedin
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Signal Transduction
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Somatomedins / physiology
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Structure-Activity Relationship
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Thionucleotides / metabolism
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Virulence Factors, Bordetella / pharmacology
Substances
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Mannosephosphates
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Peptide Fragments
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Phospholipids
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Receptor, IGF Type 2
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Receptors, Cell Surface
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Receptors, Somatomedin
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Somatomedins
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Thionucleotides
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Virulence Factors, Bordetella
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Guanosine Diphosphate
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Guanosine 5'-O-(3-Thiotriphosphate)
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Guanosine Triphosphate
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GTP-Binding Proteins
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Magnesium