Low affinity nerve growth factor receptor

Low affinity nerve growth factor receptor

The Low Affinity Nerve Growth Factor Receptor (also called the LNGFR or p75 neurotrophin receptor) is one of the two receptor types for the neurotrophins, a family of protein growth factors which stimulate neuronal cells to survive and differentiate. The precise function of the LNGFR is somewhat controversial, in contrast to the function of the high-affinity receptor family for the neurotrophins, the Trk receptor tyrosine kinases such as TrkA.

The Neurotrophins

The neurotrophins are comprised of four proteins, all of which bind to the LNGFR:
Nerve Growth Factor (NGF), Brain Derived Neurotrophic Factor (BDNF), Neurotrophin-3 (NT-3), and Neurotrophin-4 (NT-4.

Nerve growth factor, the prototypical growth factor, is a protein secreted by a neuron's target. NGF is critical for the survival and maintenance of sympathetic and sensory neurons. NGF is released from the target cells, binds to and activates its high affinity receptor (TrkA), and is internalized into the responsive neuron. The NGF/TrkA complex is subsequently trafficked back to the cell body. This movement of NGF from axon tip to soma is thought to be involved in the long-distance signaling of neurons.

The activation of TrkA by NGF is critical in inducing the survival and differentiation caused by this growth factor.

However, NGF binds at least two receptors on the surface of cells which are capable of responding to this growth factor, TrkA (pronounced "Track A") and the LNGFR.

The Trk family of receptor tyrosine kinases

TrkA is a receptor tyrosine kinase (meaning it mediates its actions by causing the addition of phosphate molecules on certain tyrosines in the cell, activating cellular signaling). There are other related Trk receptors, TrkB and TrkC. Also, there are other neurotrophic factors structurally related to NGF: BDNF (for Brain Derived Neurotrophic Factor), NT-3 (for Neurotrophin-3) and NT-4 (for Neurotrophin-4). While TrkA mediates the effects of NGF, TrkB binds and is activated by BDNF, NT-4, and NT-3, and TrkC binds and is activated only by NT-3.

The role of the LNGFR

As opposed to TrkA, the LNGFR plays a somewhat less clear role in NGF 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 in the absence of a co-expressed TrkA, 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. [Citation: Ibáñez, 2002]

Notes

References


*

*

*

*

External links

*

PBB_Controls
update_page = yes
require_manual_inspection = no
update_protein_box = yes
update_summary = no
update_citations = no


Wikimedia Foundation. 2010.

Игры ⚽ Нужна курсовая?

Look at other dictionaries:

  • Low-affinity nerve growth factor receptor — P75 redirects here. For the New Testament manuscript, see Papyrus 75. For Pentium processor at 75 MHz, see Intel P5 (microarchitecture). Nerve growth factor receptor PDB rendering based on 1sg1 …   Wikipedia

  • Nerve growth factor receptor — Nerve growth factor receptors are a group of growth factor receptors which specifically bind to neurotrophins. There are two classes of receptors, p75 and the Trk family of Tyrosine kinases receptors. p75 is a low affinity neurotrophin receptor,… …   Wikipedia

  • Nerve growth factor — (beta polypeptide) Rendering of NGF from PDB 1SG1 …   Wikipedia

  • Epidermal growth factor receptor — This article is about a cell surface receptor. For estimated measure of kidney function (eGFR), see Glomerular filtration rate. Epidermal growth factor receptor …   Wikipedia

  • Platelet-derived growth factor receptor — platelet derived growth factor receptor, alpha polypeptide Identifiers Symbol PDGFRA Entrez 5156 HUGO …   Wikipedia

  • TrkA receptor — Neurotrophic tyrosine kinase, receptor, type 1 PDB rendering based on 1he7 …   Wikipedia

  • TrkB receptor — Neurotrophic tyrosine kinase, receptor, type 2 PDB rendering based on 1hcf …   Wikipedia

  • TrkC receptor — Neurotrophic tyrosine kinase, receptor, type 3 PDB rendering based on 1wwc …   Wikipedia

  • Brain-derived neurotrophic factor — also known as BDNF is a proteincite journal | author = Binder DK, Scharfman HE | title = Brain derived neurotrophic factor | journal = Growth Factors | volume = 22 | issue = 3 | pages = 123–31 | year = 2004 | month = September | pmid = 15518235 | …   Wikipedia

  • Cell surface receptor — The seven transmembrane α helix structure of a G protein coupled receptor Cell surface receptors (membrane receptors, transmembrane receptors) are specialized integral membrane proteins that take part in communication between the cell and the… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”