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Neurotrofina

neurotrofina - Wikilingue - Encydia

The neurotrofinas, also called factors neurotróficos, are a family of proteins that favor the survival of the neurons. These substances belong to a family of factors of growth that are a type of proteins that are spilled to the blood stream and are capable of joining recipients of certain cells to stimulate its survival, growth or differentiation.

The factors neurotróficos are secreted by certain textiles, being one of its functions to prevent to the neurons reveille from initiating the programmed cellular death (apoptosis), permititiendo so the neurons survive. The neurotrofinas also induce the cellular cells differentiation progenitoras to form neurons.

The family of the neurotrofinas is formed by the factor of nervous growth (NGF, of English, nerve growth factor), the factor neurotrófico derived from the brain (BDNF, of English brain-derived neurotrophic factor), her neurotrofina-1 (NT-1), her neurotrofina-3 (NT-3), and her neurotrofina-4 (NT-4).


They belong to a class of factors of growth, secreted proteins, which are capable of sending signs to some cells so that they survive, differ, or grow. The factors of growth as the neurotrofinas who promote the survival, [1] the development and the function [2] of the neurons are known as factors neurotróficos, that are capable of signposting cells so that they survive, differ or grow. [3] The factors neurotróficos are secreted by the textile reveille and they act by means of the prevention of the neurons associated from initiating the programmed cellular death - allowing so the neurons survive. The neurotrofinas also induce the differentiation of the cells progenitoras to form neurons.

Although the majority of the neurons in the brain of the mammals forms before being born, the parts of the adult brain (for example, the sea horse) they maintain the aptitude to synthesize new neurons from cells mother; a process called neurogénesis. The neurotrofinas are chemical substances that help to stimulate and control the neurogénesis.


Content

Terminology

Some scientists use the term "neurotrofinas" like synonymous of "factor neurotrófico", [4] while the majority they reserve the term "neurotrofinas" for four related factors structurally: the factor of nervous growth (NGF), the factor neurotrófico derived from the brain (BDNF), them neurotrofinas-3 (NT-3), and them neurotrofinas-4 (NT-4).

Another factor neurotrófico, known since neurotrofina-1 new (NNT1) it is structurally related to the NGF, the BDNF, the NT-3 and the NT-4.

Recipients

There are two classes of recipients of neurotrofinas: p75 and the "TRK" of the family of recipients tirosina quinasa. [5]

Types

Factor of nervous growth

The factor of nervous growth (NGF), the factor of growth of the prototype, is a protein secreted by the cells reveille of a neuron. The NGF is critical for the survival and the maintenance of the nice and sensory neurons. The NGF liberates of the cells reveille, joins and [[neuron] activates its recipient of high affinity TrkA in [and internaliza in the sensitive neuron. The complex NGF / TrkA later is transported again to the cellular body of the neuron. This movement of the NGF of the top of the axón to the soma believes that it takes part in the long distance of signaling of the neurons.

The NGF levels have demonstrated to be significantly raised during the first year of a romantic relation.

Factor neurotrófico derived from the brain

The factor neurotrófico derived from the brain (BDNF) is a factor neurotrófico that initially was in the brain, but also it is in the periphery. More specifically, it is a protein that has the activity in certain neurons of the central nervous system and the peripheral nervous system, it helps to the survival of the existing neurons, and to promote the growth and the differentiation of new neurons and the sinapsis across axones and dendritas of germination. In the brain, it is active in the sea horse, the crust, the cerebellum, the area ventral tegmental and the previous basal brain, vital areas for learning, the memory, the motivation and the top thought. The BDNF is the second factor neurotrófico that was characterized, after the NGF and before neurotrofinas-3.

The BDNF is one of the most active substances to stimulate the neurogénesis. The mice that are born without the aptitude to synthesize BDNF suffer defects in the development of the brain and of the sensory nervous system, and usually die shortly after the birth, what he suggests that the BDNF plays an important role in the normal neurological development.

In spite of its name, the BDNF is really in a wide range of textiles and types of cells, not only the brain. Its expression can be seen in the retina, the SNC, the neurons motorboats, the kidneys and the prostate.

Neurotrofina-1 Novel

Neurotrofina-1Novel (NNT-1) also it is known like "factor 3 stimulating of the cells B" (BSF-3) or "factor 1 as factor of the citoquinas" (CLCF1), and it is a citoquina belonging to the family of interleucina-6. It is a secreted protein, which is predominantly in the lymphatic ganglions and the spleen, it contains 225 amino acids with a molecular weight of 22 kDa in its mature form. It is closely related to other proteins, calls cardiotrofina-1 and the factor neurotrófico ciliary. The term "neurotrofinas" is used commonly to refer collectively to four related factors structurally: the NGF, the BDNF, the NT-3 and the NT-4, while the NNT1 does not have any structural resemblance with these four proteins.

The NNT-1/BSF-3 induces the fosforilación of the tirosina of the recipient IL-6 of the common subunit of the glucoproteína 130 (gp130), the inhibitor of the recipient of the factor beta of the leukemia, and the factor of transcription STAT3. It has been involved in the induction of IL-1 (across the induction of the corticosterona and the IL-6) and amiloide A sérico, and in the cells hiperplasia B. This citocina is capable of the activation of the cells B across the stimulation of the recipients gp130. [6]


Neurotrofina-3

Her neurotrofina-3, or NT-3, it is a factor neurotrófico in the family of the neurotrofinas NGF. It is a protein of the factor of growth that has the activity in certain neurons of the peripheral and central nervous system, that it helps to the survival and the differentiation of the existing neurons, and to promote the growth and the differentiation of new neurons and the sinapsis. The NT-3 was the third factor neurotrófico that was characterized, after the NGF and the BDNF.

The NT-3 is only between the neurotrofinas in the number of neurons that potentially they can stimulate, considering its aptitude to activate two of the recipients of neurotrofinas tirosina quinasa (TrkC and TrkB). The mice born without the aptitude to synthesize NT-3 have loss of the propiocepción and of subcommittees of sensory neurons mecanorreceptoras.

Neurotrofina-4

Neurotrofina-4 (NT-4) is a factor neurotrófico that indicates its most across the recipient of the tirosina quinasa TrkB. Also it is known like NT4, NT5, NTF4, and NT-4 / 5. [7]


references

  1. ↑ Plantilla:Cita publication
  2. ↑ Plantilla:Cita publication
  3. ↑ Plantilla:Cita publication
  4. ↑ MeSH Neurotrophins
  5. ↑ Plantilla:Cita publication
  6. ↑ Senaldi et to., New neurotrophin-1/B cell-stimulating factor 3: to cytokine of the IL-6 family. Proc Natl Acad Sci Or S A. 1999 September 28; 96 (20):11458-63
  7. ↑ «Entrez was dated entry for NT-4/5». NCBI. Consulted 07-05-2007.


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