The neurotrophin receptor, gp75, forms a complex with the receptor tyrosine kinase TrkA
AuthorsRoss, Alonzo H.
McKinnon, Christine A.
Condon, Peter J.
Lachyankar, Mahesh B.
Stephens, Robert M.
Kaplan, David R.
Wolf, David E.
UMass Chan AffiliationsDepartment of Biochemistry and Molecular Pharmacology
Graduate School of Biomedical Sciences
Document TypeJournal Article
KeywordsAnimals; Cell Compartmentation; Cells, Cultured; Fluorescent Antibody Technique; Protein Binding; Proto-Oncogene Proteins; Receptor Protein-Tyrosine Kinases; Receptor, Nerve Growth Factor; Receptor, trkA; Receptors, Nerve Growth Factor; Recombinant Proteins; Spodoptera
Medicine and Health Sciences
MetadataShow full item record
AbstractThe high-affinity NGF receptor is thought to be a complex of two receptors , gp75 and the tyrosine kinase TrkA, but direct biochemical evidence for such an association had been lacking. In this report, we demonstrate the existence of such a gp75-TrkA complex by a copatching technique. Gp75 on the surface of intact cells is patched with an anti-gp75 antibody and fluorescent secondary antibody, the cells are then fixed to prevent further antibody-induced redistributions, and the distribution of TrkA is probed with and anti-TrkA antibody and fluorescent secondary antibody. We utilize a baculovirus-insect cell expression of wild-type and mutated NGF receptors. TrkA and gp75 copatch in both the absence and presence of NGF. The association is specific, since gp75 does not copatch with other tyrosine kinase receptors, including TrkB, platelet-derived growth factor receptor-beta, and Torso (Tor). To determine which domains of TrkA are required for copatching, we used a series of TrkA-Tor chimeric receptors and show that the extracellular domain of TrkA is sufficient for copatching with gp75. A chimeric receptor with TrkA transmembrane and intracellular domains show partial copatching with gp75. Deletion of the intracellular domain of gp75 decreases but does not eliminate copatching. A point mutation which inactivates the TrkA kinase has no effect on copatching, indicating that this enzymatic activity is not required for association with gp75. Hence, although interactions between the gp75 and TrkA extracellular domains are sufficient for complex formation, interactions involving other receptor domains also play a role.
J Cell Biol. 1996 Mar;132(5):945-53.
Permanent Link to this Itemhttp://hdl.handle.net/20.500.14038/32454
Except where otherwise noted, this item's license is described as http://creativecommons.org/licenses/by-nc-sa/4.0/
Showing items related by title, author, creator and subject.
The role of TNF-receptor family members and other TRAF-dependent receptors in bone resorptionGravallese, Ellen M.; Galson, Deborah L.; Goldring, Steven R.; Auron, Philip E. (2001-02-15)The contribution of osteoclasts to the process of bone loss in inflammatory arthritis has recently been demonstrated. Studies in osteoclast biology have led to the identification of factors responsible for the differentiation and activation of osteoclasts, the most important of which is the receptor activator of NF-kappa B ligand/osteoclast differentiation factor (RANKL/ODF), a tumor necrosis factor (TNF)-like protein. The RANKL/ODF receptor, receptor activator of NF-kappa B (RANK), is a TNF-receptor family member present on both osteoclast precursors and mature osteoclasts. Like other TNF-family receptors and the IL-1 receptor, RANK mediates its signal transduction via TNF receptor-associated factor (TRAF) proteins, suggesting that the signaling pathways activated by RANK and other inflammatory cytokines involved in osteoclast differentiation and activation are interconnected.
Mal (MyD88-adapter-like) is required for Toll-like receptor-4 signal transductionFitzgerald, Katherine A.; Palsson-McDermott, Eva M.; Bowie, Andrew G.; Jefferies, Caroline A.; Mansell, Ashley S.; Brady, Gerard; Brint, Elizabeth K.; Dunne, Aisling; Gray, Pearl; Harte, Mary T.; et al. (2001-09-07)The recognition of microbial pathogens by the innate immune system involves Toll-like receptors (TLRs), which recognize pathogen-associated molecular patterns. Different TLRs recognize different pathogen-associated molecular patterns, with TLR-4 mediating the response to lipopolysaccharide from Gram-negative bacteria. All TLRs have a Toll/IL-1 receptor (TIR) domain, which is responsible for signal transduction. MyD88 is one such protein that contains a TIR domain. It acts as an adapter, being involved in TLR-2, TLR-4 and TLR-9 signalling; however, our understanding of how TLR-4 signals is incomplete. Here we describe a protein, Mal (MyD88-adapter-like), which joins MyD88 as a cytoplasmic TIR-domain-containing protein in the human genome. Mal activates NF-kappaB, Jun amino-terminal kinase and extracellular signal-regulated kinase-1 and -2. Mal can form homodimers and can also form heterodimers with MyD88. Activation of NF-kappaB by Mal requires IRAK-2, but not IRAK, whereas MyD88 requires both IRAKs. Mal associates with IRAK-2 by means of its TIR domain. A dominant negative form of Mal inhibits NF-kappaB, which is activated by TLR-4 or lipopolysaccharide, but it does not inhibit NF-kappaB activation by IL-1RI or IL-18R. Mal associates with TLR-4. Mal is therefore an adapter in TLR-4 signal transduction.
The interferon regulatory factor, IRF5, is a central mediator of toll-like receptor 7 signalingSchoenemeyer, Annett; Barnes, Betsy J.; Mancl, Margo E.; Latz, Eicke; Goutagny, Nadege; Pitha, Paula M.; Fitzgerald, Katherine A.; Golenbock, Douglas T. (2005-02-08)Interferon regulatory factors (IRFs) are critical components of virus-induced immune activation and type I interferon regulation. IRF3 and IRF7 are activated in response to a variety of viruses or after engagement of Toll-like receptor (TLR) 3 and TLR4 by double-stranded RNA and lipopolysaccharide, respectively. The activation of IRF5, is much more restricted. Here we show that in contrast to IRF3 and IRF7, IRF5 is not a target of the TLR3 signaling pathway but is activated by TLR7 or TLR8 signaling. We also demonstrate that MyD88, interleukin 1 receptor-associated kinase 1, and tumor necrosis factor receptor-associated factor 6 are required for the activation of IRF5 and IRF7 in the TLR7 signaling pathway. Moreover, ectopic expression of IRF5 enabled type I interferon production in response to TLR7 signaling, whereas knockdown of IRF5 by small interfering RNA reduced type I interferon induction in response to the TLR7 ligand, R-848. IRF5 and IRF7, therefore, emerge from these studies as critical mediators of TLR7 signaling.