Glucose-regulated protein 78: a new partner of p53 in trophoblast.
Although wild-type p53 protein is overexpressed in first trimester trophoblast, it is inactive towards its target genes Metalloproteinase 2 and 9. This seems to be due to a complex mechanism of inactivation and stabilization of p53 relying on the formation of protein complexes involving the N-terminus of p53. To detect the proteins associated with this sequence, we incubated biotinylated p53 N-terminal peptide in cytotrophoblastic cell medium 24 h before lysis of cells. We purified the proteins retained on biotinylated peptide using a neutravidin affinity column. Proteins were then identified by peptide mass finger printing followed or not by peptide fragmentation sequencing. Among these proteins, we identified glucose-regulated protein 78 (GRP78) and verified its interaction with p53 in trophoblastic cells by immunoprecipitation and Western blot analysis. Moreover, the decreased expression of GRP78 induced by GRP78siRNA or versipelostatin decreased the formation of high molecular weight p53 complexes and p53 monomer and increased trophoblastic invasion. These results suggest that GRP78 is involved in inactivation and stabilization of p53 and in the regulation of trophoblastic invasion.
Arnaudeau
Serge
S
Bioimaging Core Facility, University Medical Center, Geneva University, Geneva, Switzerland.
Arboit
Patrizia
P
Bischof
Paul
P
Shin-ya
Kasuo
K
Tomida
A
A
Tsuruo
T
T
Irion
Olivier
O
Cohen
Marie
M
D000595:Amino Acid Sequence; D002478:Cells, Cultured; D000091342:Endoplasmic Reticulum Chaperone BiP; D005260:Female; D006360:Heat-Shock Proteins / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D010920:Placenta / Q000166:cytology; D011247:Pregnancy; D011485:Protein Binding; D025941:Protein Interaction Mapping; D014327:Trophoblasts / Q000166:cytology / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000032:analysis / Q000378:metabolism*
D000091342:Endoplasmic Reticulum Chaperone BiP; C000717247:HSPA5 protein, human; D006360:Heat-Shock Proteins; D016159:Tumor Suppressor Protein p53