TNF receptor-1 (TNF-R1) ubiquitous scaffolding and signaling protein interacts with TNF-R1 and TRAF2 via an N-terminal docking interface.
TNF receptor-1 (TNF-R1) signal transduction is mediated through the assembly of scaffolding proteins, adaptors, and kinases. TNF receptor ubiquitous scaffolding and signaling protein (TRUSS), a 90.1 kDa TNF-R1-associated scaffolding protein, also interacts with TRAF2 and IKK and contributes to TNF-alpha-induced nuclear factor-kappaB (NF-kappaB) and c-Jun-NH(2)-terminal kinase (JNK) activation. Little is known about the mechanism of interaction among TRUSS, TNF-R1, and TRAF2. To address this issue, we used deletional and site-directed mutagenesis approaches to systematically investigate (i) the regions of TRUSS that interact with TNF-R1 and TRAF2 and (ii) the ability of TRUSS to self-associate to form higher-order complexes. Here we show that sequences located in the N-terminal (residues 1-248) and central (residues 249-440) regions of TRUSS are required to form a docking interface that supports binding to both TNF-R1 and TRAF2. While the C-terminal region (residues 441-797) did not directly interact with TNF-R1 or TRAF2, sequences located in this region were capable of self-association. Collectively, these data suggest that (i) the interaction between TNF-R1 and TRAF2 requires sequences located in the entire N-terminal half (residues 1-440) of TRUSS, (ii) the binding interface for TNF-R1 is closely linked with the TRAF2 binding interface, and (iii) the assembly of homomeric TRUSS complexes may contribute to its role in TNF-R1 signaling.
Terry Powers
Jennifer L
JL
Program in Cell Biology, Department of Pediatrics, National Jewish Health, Denver, Colorado 80206, USA.
Mace
Kimberly E
KE
Parfrey
Helen
H
Lee
Shin-Je
SJ
Zhang
Gongyi
G
Riches
David W H
DW
D000595:Amino Acid Sequence; D001665:Binding Sites; D002478:Cells, Cultured; D006801:Humans; D008954:Models, Biological; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000737:chemistry / Q000378:metabolism*; D015398:Signal Transduction; D047992:TNF Receptor-Associated Factor 2 / Q000737:chemistry / Q000378:metabolism*; D050052:TRPC Cation Channels / Q000737:chemistry* / Q000378:metabolism
D047888:Receptors, Tumor Necrosis Factor, Type I; D047992:TNF Receptor-Associated Factor 2; D050052:TRPC Cation Channels; C550321:TRPC4AP protein, human