- Homeoprotein DLX-1 interacts with Smad4 and blocks a signaling pathway from activin A in hematopoietic cells. Chiba, S., Takeshita, K., Imai, Y., Kumano, K., Kurokawa, M., Masuda, S., Shimizu, K., Nakamura, S., Ruddle, F.H., Hirai, H. Proc. Natl. Acad. Sci. U.S.A. (2003)