The pro-apoptotic protein death-associated protein 3 (DAP3) interacts with the glucocorticoid receptor and affects the receptor function.
The yeast two-hybrid system was used to isolate cDNAs encoding proteins that interact with the glucocorticoid receptor (GR) ligand-binding domain in a ligand-dependent manner. One isolated cDNA encoded a fragment of death-associated protein 3 (DAP3), which has been implicated as a positive mediator of apoptosis. In vitro experiments showed that the full-length DAP3 also interacted with GR. The main interaction domain was mapped to the N-terminal region of DAP3 that had previously been shown to function in a dominant-negative fashion, protecting cells from apoptosis. Co-transfection experiments in COS-7 cells showed that DAP3 had a stimulatory effect on the ligand-induced transcriptional activation by GR and also increased the steroid-sensitivity. Furthermore, DAP3 formed a complex with several other nuclear receptors and some basic helix-loop-helix/Per-Arnt-Sim proteins, as well as with heat-shock protein 90 (hsp90) (Arnt is the aryl-hydrocarbon-receptor nuclear translocator, and Per and Sim are the Drosophila proteins Period and Single-minded). The results suggest that DAP3 could have an important role in GR action, possibly by modulating the cytoplasmic GR-hsp90 complex. Since glucocorticoids can induce apoptosis, the pro-apoptotic DAP3 protein may be involved in this function of GR.
Hulkko
S M
SM
Department of Medical Nutrition, Karolinska Institutet, Novum, S-141 86 Huddinge, Sweden. sanna.hulkko@mednut.ki.se
Wakui
H
H
Zilliacus
J
J
D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D001665:Binding Sites; D019556:COS Cells; D019281:Dimerization; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry / Q000378:metabolism*; D016601:RNA-Binding Proteins; D011965:Receptors, Glucocorticoid / Q000378:metabolism* / Q000502:physiology; D012269:Ribosomal Proteins; D014158:Transcription, Genetic; D020798:Two-Hybrid System Techniques
D051017:Apoptosis Regulatory Proteins; C097041:DAP3 protein, human; D011506:Proteins; D016601:RNA-Binding Proteins; D011965:Receptors, Glucocorticoid; D012269:Ribosomal Proteins