****************************************
* Nerve growth factor family signature *
****************************************

Nerve growth factor (NGF or beta-NGF) is a vertebrate protein that  stimulates
division and differentiation  of sympathetic and embryonic sensory neurons [1,
2]. NGF is  a protein  of  about  120  residues that is  cleaved from a larger
precursor molecule.  It  contains  six  cysteines  all  involved in intrachain
disulfide bonds.  A  schematic representation of the structure of NGF is shown
below:

                                    +------------------------+
                                    |                        |
                                    |    *******             |
        xxxxxxCxxxxxxxxxxxxxxxxxxxxxCxxxxCxxxxxCxxxxxxxxxxxxxCxCxxxx
              |                          |     |               |
              +--------------------------|-----+               |
                                         +---------------------+

'C': conserved cysteine involved in a disulfide bond.
'*': position of the pattern.

Some proteins have been found [3] to be structurally and  functionally related
to NGF, these are:

 - Brain-derived neurotrophic  factor  (BDNF), a  protein   that  promotes the
   survival of neuronal populations all located either in the central  nervous
   system or directly connected to it.
 - Neurotrophin-3 (NT-3), a  protein that  seems  to  promote  the survival of
   visceral and proprioceptive sensory neurons.
 - Neurotrophins-4/5 (NT-4/5), which  elicit  neurite outgrowth from explanted
   dorsal root  ganglia  and  could  play a role  in  oogenesis  and/or  early
   embryogenesis.

The pattern  we have developed for  the NGF family spans the central region of
these  proteins  and  include  two of the six cysteines  involved in disulfide
bonds.

-Consensus pattern: G-C-[KR]-G-[LIV]-[DE]-x(3)-[YW]-x-S-x-C
                    [The two C's are involved in disulfide bonds]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in SWISS-PROT: NONE.
-Last update: June 1994 / Pattern and text revised.

[ 1] Levi-Montalcini R.
     Science 237:1154-1162(1987).
[ 2] Bradshaw R.A., Blundell T.L., Lapatto R., McDonald N.Q., Murray-Rust J.
     Trends Biochem. Sci. 18:48-52(1993).
[ 3] Lo D.C.
     Curr. Biol. 2:67-69(1992).