| 1. |
- Larsson, Elin, et al.
(författare)
-
Purification and Characterization of the Nerve Growth Factor R221W mutant causing Insensitivity to Pain
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- We have previously identified a homozygous missense (R221W) mutation in the NGFβ gene which causes insensitivity to pain in patients. The mutation impairs the secretion of NGF and the majority of the protein accumulates as proNGF. NGF mediates its function by binding and activating the TrkA and p75 receptors and is important for the survival of the sensory and sympathetic neurons as well as the cholinergic neurons of the basal forebrain. However, the R221W mutation seems to discriminate between these types of neurons as it is the sensory neurons that are mainly affected in the patients. A second human NGFβ mutation causes a more severe form of pain insensitivity with additional anhidrosis and cognitive dysfunctions in affected patients which is also seen in patients with mutations in the gene encoding the TrkA receptor. Because R221W NGF cause a less severe phenotype we hypothesised that the mutation mainly affects the p75 interaction which is also strengthened by the fact that the substitution is located in a region known to interact with p75. In this report, we show that R221W NGF is able to bind and activate TrkA at a level comparable to wild-type NGF in cells stably expressing TrkA while the activation of the downstream target ERK1/2 is impaired in cells that co-express TrkA and p75. We also describe the effects of the mutation in terms of expression and purification properties from E.coli which indicate the likelihood that eukaryotic folding machinery is needed for correct folding of R221W NGF.
|
|
| 2. |
|
|
| 3. |
- Zeiger, Paul, 1994-, et al.
(författare)
-
Control of the phonon band gap with isotopes in hexagonal boron nitride
- 2023
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The isotopic mass of constituent elements of materials has a well-known effect on the energy of vibrational modes. By means of monochromated scanning transmission electron microscopy we have experimentally studied the phonon bandstructure of hexagonal BN, where a phonon band gap appears between in-plane optical phonon modes and the lower energy part of the phonon spectrum. The size of the phonon band gap can be manipulated by the isotopic mass of the boron. While in 11BN the phonon band gap is about 7 meV wide, in 10BN the gap nearly closes, being an order of magnitude smaller (below 0.5 meV). This opens exciting options for manipulating terahertz wave propagation through isotopically structured devices having otherwise no interfaces between chemically distinct components.
|
|
