Further, Trk TRK1, transform or tyrosine kinase protein type 1 or neurotrophic tyrosine kinase receptors, high-affinity nerve growth factor receptor known as a protein encoded by a gene NTRK1 in humans. This gene encodes a member neurotrophic tyrosine kinase receptor (NTKR) family. This kinase is a member of the MAPK pathway membrane-bound receptor, neurotrophin binding, phosphorylated (phosphorylated). It leads to cell differentiation, the presence of this kinase is may play a role in determining the sensory neuron subtypes. To dull pain in congenital anhidrosis, self cross-sectional section behavior, mental retardation, and mutations in this gene may be associated with cancer. Alternate transcriptional splice variants of this gene has been detected, but only three have been characterized so far.
Neurotrophins TrkA is a high affinity receptor catalysts and “NGF” or nerve growth factor. Thus, for example, prevent the programmed cell death and neuronal differentiation, to mediate many effects of NGF. Family. It is a part of the sub-family of protein kinases, including the TrkA TrkC’s and, of TrkB. BDNF (brain-derived neurotrophic factor), NT-3 NT-4 and (neurotrophin -3) (neurotrophin 4): In addition, there is a nerve and other factors related to NGF structurally. The TrkA’s, while mediating the action of NGF, TrkB for is active and bound by NT-3 BDNF, and NT-4. Furthermore, TrkC binds of, and is activated by NT-3. Neurotrophic growth factor receptor Night
There is a receptor of TrkA “LNGFR” than NGF (called the “low-affinity nerve growth factor receptor”). Unlike the TrkA, and plays a role somewhat less clear in the biology of NGF of LNGFR. Some researchers has functioned as a “sink” for neurotrophins connections and demonstrate the LNGFR. Cells expressing both Trk receptor with LNGFR, you can have a high activity – as they have a high “microconcentration” of neurotrophin. But also in the absence of TrkA that co-expression of LNGFR, it may signal the cells to die by apoptosis – the living neurotrophins in the presence of cells expressing the LNGFR in the presence of Trk receptors and likely to die than are at.
The TrkA was cloned from colon tumor originally cancer caused by the displacement which leads to activation of the kinase domain of the TrkA. However, TrkA itself does not seem to be in the cancer gene. In one study, was found keratoconus corneas influenced elevated levels SP3 repressor isoform transcription factor total absence of receptor TrkA. Levels of various proteins may be controlled by “ubiquitin / proteasome system.” This so-called “ubiquitin” in the system is small (7-8 KD) protein is disposed on the target protein, and is led to the destruction by a device known as a “proteasome” therefore. The TrkA is targeted called NEDD-4 the proteasome-mediated destruction of “E3 ubiquitin ligase”. This mechanism may be different for the control of neuronal survival. To some extent, the type of ubiquitiniation TrkA probably can be adjusted by extraneous other receptors for NGF, the p75NTR.
In order to deal with whether to adjust the level of TrkA, endogenous expression of NEDD4-2 are infected with lentiviruses DRG neurons expressing shRNA specific interrupt the DD4-2 NE we. It suggests that these neurons are an excellent model for the study of the receptor TrkA and in vitro NGF, developing top DRG neurons express TrkA of you, is dependent on NGF for survival. Therefore, we incubated them in the presence of NGF for receiving the DRG neurons from E15.5 rat embryos, selects the expression neurons TrkA (a 50ng / ml) of. Were then infected shRNA Lentiviral of NEDD4-2 day control and in the in vitro (DIV) 4 to adjust the NEDD4-2 protein levels neurons. As used herein, the degree of infection for performing the biochemical tests and all were reported to be at least 90% as indicated by GFP expression. To evaluate the NEDD4-2 protein levels and cell lysate neurons infected and subjected to Western blot analysis. Infection of shRNA lentivirus of NEDD4-2 has provided a dramatic reduction in the level of NEDD4-2 protein endogenous.
NEDD4-2 depletion, the total amount of TrkA increases the level of p75, while it was not affected at the same time. In order to assess whether it is possible NEDD4-2 depletion affect the surface expression of NGF receptors, we performed experiments biotinylated. The biotin-labeled surface proteins from DRG neurons were infected, and was pulled down by Neutroavidin beads. To increase the surface of TrkA but, P75 surface level is not had increased to NEDD4-2 after depletion. Quantification of data corresponding to different experiments are NEDD4 -2 compared to the control, neurons and total TrkA – showed an increase of 88% of the level increase of 46% of the level of the surface TrkA in depleted neurons. There was no significant difference in levels of p75 observed. These results suggest that rather than adhering to the surface of TrkA and total endogenous NEDD4-2 in sensory neurons, to regulate the amount of P75.
Because there is a possibility that ubiquitination several proteins, the shRNA, could adversely impact directly and indirectly more than one on top of the protein TrkA is NEDD4-2. If you want to exclude the possibility that can be the result of an indirect effect, our results, in accordance with the experimental approach that we are different. Therefore, the bond breaking of one NEDD4-2 to TrkA we. Rather than motifs present within the previous PPVY785 TrkA, TrkB’s will be required for the binding of NEDD4-2. Thus have reported us, to be raised in the mouse second, we point mutations of TrkA protein is a codon 782, which encodes a proline was replaced by the amino acids present in serine, of TrkB carry. This mutant protein does not bind to NEDD4-2 If you lack the PPVY motif of TrkA, but you can still be engaged in the PLC-G. The targeting vector was constructed by introducing the code of serine 782 in the 17 proline codons changed two exons.
And confirmed by sequencing, loss of restriction sites, the presence of these changes, the BstXI. Targeted ES cells were monitored by Southern blot and the inner cylinder and the outer cylinder, as described in Materials and Methods. It is a fertile knock-in mouse TrkA P782S a (KI) can be performed, and normal life. Respectively, to strengthen a fragment of 1185 base pairs and KI WT and BP 1385, was performed by PCR, genotyping of mice. The presence of the mutation was evaluated by presence or absence of the PCR fragment digested with BstXI in KI mice. In order to confirm that it is possible DNA mutant was amplified consumed, we used a PstI restriction site.