The WSXWS Motif in Cytokine Receptors Is a Molecular Switch Involved in Receptor Activation: Insight from Structures of the Prolactin Receptor
Dagil, R., Knudsen, M.J., Olsen, J.G., O'Shea, C., Franzmann, M., Goffin, V., Teilum, K., Breinholt, J., Kragelund, B.B.(2012) Structure 20: 270-282
- PubMed: 22325776
- DOI: https://doi.org/10.1016/j.str.2011.12.010
- Primary Citation of Related Structures:
2LFG - PubMed Abstract:
The prolactin receptor (PRLR) is activated by binding of prolactin in a 2:1 complex, but the activation mechanism is poorly understood. PRLR has a conserved WSXWS motif generic to cytokine class I receptors. We have determined the nuclear magnetic resonance solution structure of the membrane proximal domain of the human PRLR and find that the tryptophans of the motif adopt a T-stack conformation in the unbound state. By contrast, in the hormone bound state, a Trp/Arg-ladder is formed. The conformational change is hormone-dependent and influences the receptor-receptor dimerization site 3. In the constitutively active, breast cancer-related receptor mutant PRLR(I146L), we observed a stabilization of the dimeric state and a change in the dynamics of the motif. Here we demonstrate a structural link between the WSXWS motif, hormone binding, and receptor dimerization and propose it as a general mechanism for class 1 receptor activation.
Organizational Affiliation:
Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen, Denmark.