Identification of a protein with homology to hsp90 that binds the type 1 tumor necrosis factor receptor.
The yeast-based two hybrid has been used to identify a novel protein that binds to the intracellular domain of the type 1 receptor for tumor necrosis factor (TNFR-1IC). The TNF receptor-associated protein, TRAP-1, shows strong homology to members of the 90-kDa family of heat shock proteins. After in vitro transcription/translation and 35S labeling, TRAP-1 was precipitated using a fusion protein consisting of glutathione S-transferase and TNFR-1IC, showing that the two proteins directly interact. The ability of deletion mutants of TNFR-1 to interact with TRAP-1 was tested using the two hybrid system. This showed that the amino acid sequences that mediate binding are diffusely distributed outside of the domain in the C terminus of TNFR-1IC that signals cytotoxicity. The 2.4-kilobase TRAP-1 mRNA was variably expressed in skeletal muscle, liver, heart, brain, kidney, pancreas, lung, and placenta. TRAP-1 mRNA was also detected in each of eight different transformed cell lines. Identification of TRAP-1 may be an important step toward defining how TNFR-1, which does not contain protein tyrosine kinase activity, transmits its message to signal transduction pathways.
Song
H Y
HY
Department of Physiology and Biophysics, Indiana University School of Medicine, Indianapolis 46202.
Dunbar
J D
JD
Zhang
Y X
YX
Guo
D
D
Donner
D B
DB
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D018076:DNA, Complementary; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D011485:Protein Binding; D051381:Rats; D018124:Receptors, Tumor Necrosis Factor / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction
D018076:DNA, Complementary; D018841:HSP90 Heat-Shock Proteins; D018124:Receptors, Tumor Necrosis Factor; C092306:TRAP1 protein, human