The cytokine interleukin-5 (IL-5) induces the proliferation and differentiation of various blood cells through its receptor, IL-5R. Although the β subunit of the IL-5R is similar to other receptors, the α subunit is specific for IL-5 signaling. Geijsen et al. have explored IL-5 specificity and report that
IL-5Rα interacts with the PDZ-domain-containing protein syntenin, and that syntenin interacts with the transcriptional activator Sox4. In cytokine-receptor signaling, syntenin is critical for IL-5-mediated activation of Sox4. Thus, a mechanism of transcriptional activation by cytokine-specific receptor subunits has been elucidated. The IL-5R-induced activation of Sox4 may play a role in the regulation of early B cell proliferation and may function in the differentiation of other hematopoietic cells.
N. Geijsen, I. J. Uings, C. Pals, J. Armstrong, M. McKinnon, J. A. M. Raaijmakers, J.-W. J. Lammers, L. Koenderman, P. J. Coffer, Cytokine-specific transcriptional regulation through an IL-5Rα interacting protein. Science 293, 1136-1138 (2001). [Abstract] [Full Text]