GMFB is a nerve growth factor which belongs to the actin-binding proteins ADF family, GMF subfamily. GMFB is involved in nervous system development, angiogenesis and immune function. It is especially crucial for the nervous system. GMFB causes brain cell differentiation, stimulates neural regeneration and inhibits tumor cell proliferation. It contains 1 ADF-H domain and is phosphorylated after phorbol ester stimulation. GMFB overexpression in astrocytes results in the increase of BDNF production. GMFB expression is increased by exercise, thus BDNF is important for exercise-induction of BDNF.