Cripto interaction with ALK4 is necessary both
for Nodal binding to the ALK4/ActR-IIB receptor complex and for Smad2
activation by Nodal.Yeo
C, Whitman M.
Activin increases gene expression of the PAX4,
one of the major transcription factors determining pancreatic beta
cell differentiation. This effect was mediated, at least in part, by
the type IB activin receptor (ALK4). Ueda