A mechanistic study of the Swedish NGF mutation (NGFR100W) : trophic signaling versus nociception
- Nerve growth factor (NGF) exerts multiple functions, e.g. trophic or nociceptive, on target neurons throughout development. The recent discovery of a point mutation in NGF [beta] (NGFR100W) in patients with hereditary sensory and autonomic neuropathy, type V (HSAN V) made it possible to distinguish the signaling mechanisms that lead to the two different functional outcomes of NGF. We recently the developed novel method to produce mono-biotinylated NGF that can be used for single molecule studies using a mammalian expression system. We confirmed that the mono-biotinylated NGF is mature and biologically active comparably to purified NGF from mice maxillary glands. We produced and purified the mutant NGF (NGFR100W) along with its wild type counterpart (wtNGF) using this mammalian expression system. We performed extensive biochemical, cellular, and live imaging experiments to examine the binding and signaling properties of NGFR100W. Our results showed that, similar to wtNGF, NGFR100W bound and activated TrkA receptor and its downstream signaling pathways to support neuronal survival and differentiation. However, NGFR100W failed to bind and stimulate p75NTR mediated signaling cascades. Furthermore, NGFR100W no longer had the ability to induce hyper-potentiation of dorsal root ganglion (DRG) neurons as detected by single cell patching clamp assay. Intraplantar injection of NGFR100W into adult rats induced neither thermal nor mechanical hyperalgesia. Taken together, our results demonstrate that, NGFR100W retains trophic support capability through TrkA, but no longer is involved in mediating pain functions through the p75NTR signaling pathways. These results may explain the increase in pain threshold and loss of pain perception in HSAN V patients.
|Type of resource
|electronic; electronic resource; remote
|1 online resource.
|Sung, Ki Jung
|Stanford University, Biophysics Program.
|Mobley, William C
|Mobley, William C
|Statement of responsibility
|Ki Jung Sung.
|Submitted to the Program in Biophysics.
|Thesis (Ph.D.)--Stanford University, 2013.
- © 2013 by Ki Jung Sung
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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