| Type: | Family | Name: | Nerve growth factor-like |
| Description: | During the development of the vertebrate nervous system, many neurons become redundant (because they have died, failed to connect to targetcells, etc.) and are eliminated. At the same time, developing neurons send out axon outgrowths that contact their target cells []. Such cells controltheir degree of innervation (the number of axon connections) by the secretion of various specific neurotrophic factors that are essential forneuron survival. One of these is nerve growth factor (NGF or beta-NGF), a vertebrate protein that stimulates division and differentiation of sympathetic and embryonic sensory neurons [, ]. NGF is mostly found outside the centralnervous system (CNS), but slight traces have been detected in adult CNS tissues, although a physiological role for this is unknown []; it has alsobeen found in several snake venoms [, ].NGF is a protein of about 120 residues that is cleaved from a larger precursor molecule. It contains six cysteines all involved in intrachaindisulphide bonds. A schematic representation of the structure of NGF is shown below:+------------------------+ | || | xxxxxxCxxxxxxxxxxxxxxxxxxxxxCxxxxCxxxxxCxxxxxxxxxxxxxCxCxxxx| | | | +--------------------------|-----+ |+---------------------+ 'C': conserved cysteine involved in a disulphide bond.This entry also contains NGF-related proteins such as neutrophin 3, which promotes the survival of visceral and proprioceptive sensory neurons, and brain-derived neurotrophin, which promotes the survival of neuronal populations that are located either in the central nervous system or directly connected to it [, ]. | Short Name: | Nerve_growth_factor-like |
