Gene Summary: NTRK1 gene encodes a member of the neurotrophic tyrosine kinase receptor (NTKR) family. This kinase is a membrane-bound receptor that, upon neurotrophin binding, phosphorylates itself and members of the MAPK pathway. The presence of this kinase leads to cell differentiation and may play a role in specifying sensory neuron subtypes. Mutations in NTRK1 gene have been associated with congenital insensitivity to pain, anhidrosis, self-mutilating behavior, mental retardation and cancer. Alternate transcriptional splice variants of NTRK1 gene have been found, but only three have been characterized to date. [provided by RefSeq, Jul 2008]General information above from NCBI
Catalytic activity: ATP + a [protein]-L-tyrosine = ADP + a [protein]-L-tyrosine phosphate.
Enzyme regulation: The pro-survival signaling effect of NTRK1 in neurons requires its endocytosis into signaling early endosomes and its retrograde axonal transport. This is regulated by different proteins including CFL1, RAC1 and SORT1. NTF3 is unable to induce this signaling probably due to the lability of the NTF3- NTRK1 complex in endosomes. SH2D1A inhibits the autophosphorylation of the receptor, and alters the recruitment and activation of downstream effectors and signaling cascades (By similarity). Regulated by NGFR (By similarity).
Subunit structure: Exists in a dynamic equilibrium between monomeric (low affinity) and dimeric (high affinity) structures. Homodimerization is induced by binding of a NGF dimer. Interacts with SQSTM1; bridges NTRK1 to NGFR. Forms a ternary complex with NGFR and KIDINS220; this complex is affected by the expression levels of KIDINS220 and an increase in KIDINS220 expression leads to a decreased association of NGFR and NTRK1 (By similarity). Interacts with SH2D1A; regulates NTRK1 (By similarity). Interacts (phosphorylated upon activation by NGF) with SHC1; mediates SHC1 phosphorylation and activation. Interacts (phosphorylated upon activation by NGF) with PLCG1; mediates PLCG1 phosphorylation and activation. Interacts (phosphorylated) with SH2B1 and SH2B2. Interacts with GRB2. Interacts with PIK3R1. Interacts with FRS2. Interacts with SORT1; may regulate NTRK1 anterograde axonal transport. Interacts with RAB7A (By similarity).
Domain: The transmembrane domain mediates interaction with KIDINS220 (By similarity).
The extracellular domain mediates interaction with NGFR (By similarity).
Subcellular location: Cell membrane; Single-pass type I membrane protein. Early endosome membrane; Single-pass type I membrane protein (By similarity). Note=Internalized to endosomes upon binding of NGF or NTF3 and further transported to the cell body via a retrograde axonal transport (By similarity).
Tissue specificity: Isoform TrkA-I is found in most non-neuronal tissues. Isoform TrkA-II is primarily expressed in neuronal cells. TrkA-III is specifically expressed by pluripotent neural stem and neural crest progenitors.
Induction: Isoform TrkA-III is up-regulated upon hypoxia in cells normally expressing it.
Post-translational: Ligand-mediated autophosphorylation. Interaction with SQSTM1 is phosphotyrosine-dependent. Autophosphorylation at Tyr-496 mediates interaction and phosphorylation of SHC1.
N-glycosylated (Probable). Isoform TrkA-I is N-glycosylated.
Ubiquitinated. Undergoes polyubiquitination upon activation; regulated by NGFR. Ubiquitination regulates the internalization of the receptor (By similarity).
Involvement in disease: Congenital insensitivity to pain with anhidrosis (CIPA) [MIM:256800]: Characterized by a congenital insensitivity to pain, anhidrosis (absence of sweating), absence of reaction to noxious stimuli, self-mutilating behavior, and mental retardation. This rare autosomal recessive disorder is also known as congenital sensory neuropathy with anhidrosis or hereditary sensory and autonomic neuropathy type IV or familial dysautonomia type II. Note=The disease is caused by mutations affecting the gene represented in this entry.
Thyroid papillary carcinoma (TPC) [MIM:188550]: A common tumor of the thyroid that typically arises as an irregular, solid or cystic mass from otherwise normal thyroid tissue. Papillary carcinomas are malignant neoplasm characterized by the formation of numerous, irregular, finger-like projections of fibrous stroma that is covered with a surface layer of neoplastic epithelial cells. Note=The gene represented in this entry is involved in disease pathogenesis. Chromosomal aberrations involving NTRK1 are found in thyroid papillary carcinomas. Translocation t(1;3)(q21;q11) with TFG generates the TRKT3 (TRK-T3) transcript by fusing TFG to the 3'-end of NTRK1; a rearrangement with TPM3 generates the TRK transcript by fusing TPM3 to the 3'-end of NTRK1; an intrachromosomal rearrangement that links the protein kinase domain of NTRK1 to the 5'-end of the TPR gene forms the fusion protein TRK-T1. TRK-T1 is a 55 kDa protein reacting with antibodies against the C-terminus of the NTRK1 protein.
Sequence similarity: Belongs to the protein kinase superfamily. Tyr protein kinase family. Contains 2 Ig-like C2-type (immunoglobulin-like) domains.
Contains 2 LRR (leucine-rich) repeats.
Contains 1 LRRCT domain.
Contains 1 protein kinase domain.
General information above from UniProt