TrkC receptor

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Neurotrophic tyrosine kinase, receptor, type 3
Protein NTRK3 PDB 1wwc.png
PDB rendering based on 1wwc.
Available structures
PDB Ortholog search: PDBe, RCSB
Identifiers
Symbols NTRK3 ; TRKC; gp145(trkC)
External IDs OMIM191316 MGI97385 HomoloGene49183 ChEMBL: 5608 GeneCards: NTRK3 Gene
EC number 2.7.10.1
RNA expression pattern
PBB GE NTRK3 215025 at tn.png
PBB GE NTRK3 206462 s at tn.png
PBB GE NTRK3 215115 x at tn.png
More reference expression data
Orthologs
Species Human Mouse
Entrez 4916 18213
Ensembl ENSG00000140538 ENSMUSG00000059146
UniProt Q16288 Q6VNS1
RefSeq (mRNA) NM_001007156 NM_008746
RefSeq (protein) NP_001007157 NP_032772
Location (UCSC) Chr 15:
88.42 – 88.8 Mb
Chr 7:
78.19 – 78.58 Mb
PubMed search [1] [2]

NT-3 growth factor receptor also known as neurotrophic tyrosine kinase receptor type 3 or TrkC tyrosine kinase or Trk-C receptor is a protein that in humans is encoded by the NTRK3 gene.[1]

TrkC is the high affinity catalytic receptor for the neurotrophin NT-3 (neurotrophin-3). As such, TrkC mediates the multiple effects of this neurotrophic factor, which includes neuronal differentiation and survival.

The TrkC receptor is part of the large family of receptor tyrosine kinases. A "tyrosine kinase" is an enzyme which is capable of adding a phosphate group to the certain tyrosines on target proteins, or "substrates". A receptor tyrosine kinase is a "tyrosine kinase" which is located at the cellular membrane, and is activated by binding of a ligand via its extracellular domain. Other example of tyrosine kinase receptors include the insulin receptor, the IGF-1 receptor, the MuSK protein receptor, the Vascular Endothelial Growth Factor (or VEGF) receptor, etc. The "substrate" proteins which are phosphorylated by TrkC include PI3 kinase.

Family Members[edit]

TrkC is part of a sub-family of protein kinases which includes TrkA and TrkB. Also, there are other neurotrophic factors structurally related to NT-3: NGF (for Nerve Growth Factor), BDNF (for Brain Derived Neurotrophic Factor) and NT-4 (for Neurotrophin-4). While TrkB mediates the effects of BDNF, NT-4 and NT-3, TrkA is bound and thereby activated only by NGF. Further, TrkC binds and is activated only by NT-3.

TrkB binds BDNF and NT-4 more strongly than it binds NT-3. TrkC binds NT-3 more strongly than TrkB does.

The LNGFR[edit]

There is one other NT-3 receptor family besides the Trks (TrkC & TrkB), called the "LNGFR" (for "low affinity nerve growth factor receptor"). As opposed to TrkC, the LNGFR plays a somewhat less clear role in NT-3 biology. Some researchers have shown the LNGFR binds and serves as a "sink" for neurotrophins. Cells which express both the LNGFR and the Trk receptors might therefore have a greater activity - since they have a higher "microconcentration" of the neurotrophin. It has also been shown, however, that the LNGFR may signal a cell to die via apoptosis - so therefore cells expressing the LNGFR in the absence of Trk receptors may die rather than live in the presence of a neurotrophin.

References[edit]

  1. ^ McGregor LM, Baylin SB, Griffin CA, Hawkins AL, Nelkin BD (July 1994). "Molecular cloning of the cDNA for human TrkC (NTRK3), chromosomal assignment, and evidence for a splice variant". Genomics 22 (2): 267–72. doi:10.1006/geno.1994.1383. PMID 7806211. 

Further reading[edit]