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Proteomic identification of glucocorticoid receptor interacting proteins
Author(s) -
Hedman Erik,
Widén Christina,
Asadi Abolfazl,
Dinnetz Ingrid,
Schröder Wolfgang P.,
Gustafsson JanÅke,
Wikström AnnCharlotte
Publication year - 2006
Publication title -
proteomics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.26
H-Index - 167
eISSN - 1615-9861
pISSN - 1615-9853
DOI - 10.1002/pmic.200500266
Subject(s) - glucocorticoid receptor , identification (biology) , computational biology , proteomics , biology , receptor , chemistry , biochemistry , gene , ecology
The glucocorticoid receptor (GR) acts as a ligand dependent transcription factor but can also cross talk with other signaling pathways via protein‐protein interactions. In this paper we describe methods to study novel cytosolic GR interacting proteins, using mAb based immunoaffinity chromatography of GR from rat liver cytosol. Co‐purifying proteins were identified by 2‐DE in combination with MALDI‐TOF‐MS. Non‐liganded/non‐activated and in vitro liganded/activated GR, respectively, co‐purifies with specific sets of proteins. Of these 34 were conclusively identified, seven have previously been reported to be part of the GR‐complex, revealing 27 new possible interacting candidates for the GR‐complex. Of the novel GR interacting proteins the major vault protein , TATA binding interacting protein 49a and glycoprotein PP63 were of special interest. Furthermore, using 2‐D DIGE we show that the set of proteins interacting with non‐liganded GR is distinctly different in protein amount compared to the proteins found with liganded/activated GR. This suggests the presence of different GR complexes in the cell, which was further substantiated by the finding of several separate GR native protein complexes, “GR‐receptosomes”, using blue native gel electrophoresis. Our findings suggest the existence of several new mechanisms for GR signaling and regulation.