Crystal structure of an affinity-matured prolactin complexed to its dimerized receptor reveals the topology of hormone binding site 2.

TY - JOUR

T1 - Crystal structure of an affinity-matured prolactin complexed to its dimerized receptor reveals the topology of hormone binding site 2.

AU - Broutin, Isabelle

AU - Jomain, Jean-Baptiste

AU - Tallet, Estelle

AU - Van Agthoven, Jan

AU - Raynal, Bertand

AU - Hoos, Sylviane

AU - Kragelund, Birthe Brandt

AU - Kelly, Paul

AU - Ducroix, Alexandre

AU - England, Patrick

AU - Goffin, Vincent

PY - 2010/3/12

Y1 - 2010/3/12

N2 - We report the first crystal structure of a 1:2 hormone·receptor complex that involves prolactin (PRL) as the ligand, at 3.8-Å resolution. Stable ternary complexes were obtained by generating affinity-matured PRL variants harboring an N-terminal tail from ovine placental lactogen, a closely related PRL receptor (PRLR) ligand. This structure allows one to draw up an exhaustive inventory of the residues involved at the PRL·PRLR site 2 interface, consistent with all previously reported site-directed mutagenesis data. We propose, with this description, an interaction model involving three structural components of PRL site 2 ("three-pin plug"): the conserved glycine 129 of helix α3, the hydrogen bond network involving surrounding residues (glycine cavity), and the N terminus. The model provides a molecular basis for the properties of the different PRL analogs designed to date, including PRLR antagonists. Finally, comparison of our 1:2 PRL·PRLR 2 structure with those of free PRL and its 1:1 complex indicates that the structure of PRL undergoes significant changes when binding the first, but not the second receptor. This suggests that the second PRLR moiety adapts to the 1:1 complex rather than the opposite. In conclusion, this structure will be a useful guiding tool for further investigations of the molecular mechanisms involved in PRLR dimerization and activation, as well as for the optimization of PRLR antagonists, an emerging class of compounds with high therapeutic potential against breast and prostate cancer.

AB - We report the first crystal structure of a 1:2 hormone·receptor complex that involves prolactin (PRL) as the ligand, at 3.8-Å resolution. Stable ternary complexes were obtained by generating affinity-matured PRL variants harboring an N-terminal tail from ovine placental lactogen, a closely related PRL receptor (PRLR) ligand. This structure allows one to draw up an exhaustive inventory of the residues involved at the PRL·PRLR site 2 interface, consistent with all previously reported site-directed mutagenesis data. We propose, with this description, an interaction model involving three structural components of PRL site 2 ("three-pin plug"): the conserved glycine 129 of helix α3, the hydrogen bond network involving surrounding residues (glycine cavity), and the N terminus. The model provides a molecular basis for the properties of the different PRL analogs designed to date, including PRLR antagonists. Finally, comparison of our 1:2 PRL·PRLR 2 structure with those of free PRL and its 1:1 complex indicates that the structure of PRL undergoes significant changes when binding the first, but not the second receptor. This suggests that the second PRLR moiety adapts to the 1:1 complex rather than the opposite. In conclusion, this structure will be a useful guiding tool for further investigations of the molecular mechanisms involved in PRLR dimerization and activation, as well as for the optimization of PRLR antagonists, an emerging class of compounds with high therapeutic potential against breast and prostate cancer.

U2 - 10.1074/jbc.m109.089128

DO - 10.1074/jbc.m109.089128

M3 - Journal article

C2 - 20053995

SN - 0021-9258

VL - 285

SP - 8422

EP - 8433

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

IS - 11

ER -