title: Absence of interaction between doppel and GFAP, Grb2, PrPc proteins in human tumor astrocytic cells.
abstract: BACKGROUND
  The doppel protein (Dpl) is a newly recognized cellular prion protein (PrP(C))-like molecule encoded by a novel gene locus, PRND, located on the same chromosomal region of the PrP(C) coding gene. Recently, Dpl was shown to be aberrantly expressed in astrocytic tumor specimens and in astrocytoma-derived cell lines, showing a peculiar cytoplasmic localization. Here, Dpl interactions with some of the prion-interacting proteins were studied. In particular, whether the tumor astrocytic environment is suitable for doppel interaction with GFAP and Grb2 proteins, as well as with the PrPC protein itself was investigated.
  
  
  METHODS
  In order to verify our hypothesis, an innovative mammalian two-hybrid system and co-immunoprecipitation assays were employed.
  
  
  RESULTS
  The results reported the absence of protein interactions. Our findings provided evidence that, in our astrocytoma cell-based model, Dpl does not share with PrP(C) the ability to interact with GFAP and Grb2.
  
  
  CONCLUSIONS
  Identifying Dpl ligands may provide new insights into the involvement of Dpl in astrocytoma tumor progression.
authors.affiliation: Dipartimento di Genetica e Microbiologia, Università di Pavia, via Ferrata 1, 27100 Pavia, Italy. alberto@ipvgen.unipv.it
authors.forename: Alberto
authors.initials: A
authors.lastname: Azzalin
authors.forename: Igor
authors.initials: I
authors.lastname: Del Vecchio
authors.forename: Laurent R
authors.initials: LR
authors.lastname: Chiarelli
authors.forename: Giovanna
authors.initials: G
authors.lastname: Valentini
authors.forename: Sergio
authors.initials: S
authors.lastname: Comincini
authors.forename: Luca
authors.initials: L
authors.lastname: Ferretti
mesh_terms: D001254:Astrocytoma / Q000378:metabolism*; D058851:GPI-Linked Proteins; D051380:GRB2 Adaptor Protein / Q000378:metabolism*; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D047468:Immunoprecipitation; D018621:PrPC Proteins / Q000378:metabolism*; D011328:Prions / Q000378:metabolism*
chemical_list: D058851:GPI-Linked Proteins; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; D005904:Glial Fibrillary Acidic Protein; C501125:PRND protein, human; D018621:PrPC Proteins; D011328:Prions