Transforming growth factor-beta (TGF-beta) and its related proteins re
gulate broad aspects of body development, including cell proliferation
, differentiation, apoptosis and gene expression, in various organisms
. Deregulated TGF-beta function has been causally implicated in the ge
neration of human fibrotic disorders and in tumor progression. Neverth
eless, the molecular mechanisms of TGF-beta action remained essentiall
y unknown until recently. Here, we discuss recent progress in our unde
rstanding of the mechanism of TGF-beta signal transduction with respec
t to the regulation of gene expression, the control of cell phenotype
and the potential usage of TGF-beta for the treatment of human disease
s.