Absence of interaction between doppel and GFAP, Grb2, PrPc proteins in human tumor astrocytic cells.
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.
Azzalin
Alberto
A
Dipartimento di Genetica e Microbiologia, Università di Pavia, via Ferrata 1, 27100 Pavia, Italy. alberto@ipvgen.unipv.it
Del Vecchio
Igor
I
Chiarelli
Laurent R
LR
Valentini
Giovanna
G
Comincini
Sergio
S
Ferretti
Luca
L
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*
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