TY - JOUR
T1 - The basic helix-loop-helix/PAS factor Sim is associated with hsp90
T2 - Implications for regulation by interaction with partner factors
AU - McGuire, Jacqueline
AU - Coumailleau, Pascal
AU - Whitelaw, Murray L.
AU - Gustafsson, Jan Åke
AU - Poellinger, Lorenz
N1 - Copyright:
Copyright 2007 Elsevier B.V., All rights reserved.
PY - 1995/12/29
Y1 - 1995/12/29
N2 - Sim is a Drosophila developmental basic helix-loop-helix (bHLH) transcription factor containing a Per-Arnt-Sim (PAS) region of homology. Here we demonstrate that Sim, in analogy to the structurally related hHLH/PAS dioxin receptor, was stably associated with the molecular chaperone hsp90. In the case of the dioxin receptor, release of hsp90 and derepression of receptor function appear to be regulated by ligand binding and dimerization with Arnt, a non-hsp90-associated bHLH/PAS factor. Dimerization with Arnt very efficiently disrupted Sim-hsp90 interaction, a process that required both the bHLH and PAS dimerization motifs of Arnt. Moreover, hsp90 was also released upon dimerization of Sim with the Drosophila PAS factor Per, whereas the hsp90-associated dioxin receptor failed to interact with Sim. These results indicate that hsp90 may play a role in conditional regulation of Sim function, and that Per and possibly bHLH/PAS partner factors may activate Sim by inducing release of hsp90 during the dimerization process.
AB - Sim is a Drosophila developmental basic helix-loop-helix (bHLH) transcription factor containing a Per-Arnt-Sim (PAS) region of homology. Here we demonstrate that Sim, in analogy to the structurally related hHLH/PAS dioxin receptor, was stably associated with the molecular chaperone hsp90. In the case of the dioxin receptor, release of hsp90 and derepression of receptor function appear to be regulated by ligand binding and dimerization with Arnt, a non-hsp90-associated bHLH/PAS factor. Dimerization with Arnt very efficiently disrupted Sim-hsp90 interaction, a process that required both the bHLH and PAS dimerization motifs of Arnt. Moreover, hsp90 was also released upon dimerization of Sim with the Drosophila PAS factor Per, whereas the hsp90-associated dioxin receptor failed to interact with Sim. These results indicate that hsp90 may play a role in conditional regulation of Sim function, and that Per and possibly bHLH/PAS partner factors may activate Sim by inducing release of hsp90 during the dimerization process.
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U2 - 10.1074/jbc.270.52.31353
DO - 10.1074/jbc.270.52.31353
M3 - Article
C2 - 8537407
AN - SCOPUS:0029611034
VL - 270
SP - 31353
EP - 31357
JO - The Journal of biological chemistry
JF - The Journal of biological chemistry
SN - 0021-9258
IS - 52
ER -