Engineering synthetic antibody binders for allosteric inhibition of prolactin receptor signaling

TitleEngineering synthetic antibody binders for allosteric inhibition of prolactin receptor signaling
Publication TypeJournal Article
Year of Publication2015
AuthorsRizk, S. S., Kouadio J. L., Szymborska A., Duguid E. M., Mukherjee S., Zheng J., Clevenger C. V., and Kossiakoff A. A.
JournalCell Commun Signal
Date Published01/2015
ISSN1478-811X (Electronic) 1478-811X (Linking)

BackgroundMany receptors function by binding to multiple ligands, each eliciting a distinct biological output. The extracellular domain of the human prolactin receptor (hPRL-R) uses an identical epitope to bind to both prolactin (hPRL) and growth hormone (hGH), yet little is known about how each hormone binding event triggers the appropriate response.FindingsHere, we utilized a phage display library to generate synthetic antibodies (sABs) that preferentially modulate hPRL-R function in a hormone-dependent fashion. We determined the crystal structure of a sAB-hPRL-R complex, which revealed a novel allosteric mechanism of antagonism, whereby the sAB traps the receptor in a conformation more suitable for hGH binding than hPRL. This was validated by examining the effect of the sABs on hormone internalization via the hPRL-R and its downstream signaling pathway.ConclusionsThe findings suggest that subtle structural changes in the extracellular domain of hPRL-R induced by each hormone determine the biological output triggered by hormone binding. We conclude that sABs generated by phage display selection can detect these subtle structural differences, and therefore can be used to dissect the structural basis of receptor-ligand specificity.


University of Toronto  UCSF  The University of Chicago  QB3  Chicago Biomedical Consortium