The orphan GPR50 receptor promotes constitutive TGFβ receptor signaling and protects against cancer development

• DOI: 10.1038/s41467-018-03609-x
• Publication Date: 2018-03-19T19:39:56Z
• Authors: Stefanie Wojciech; Raise Ahmad; Zakia Belaid-Chou...; Anne-Sophie Journé; Sarah Gallet; Julie Dam; Avais Daulat; Delphine Ndiaye-L...; Olivier Lahuna; Angeliki Karamitri; Jean-Luc Guillaume; Marcio Do Cruzeiro; François Guillonneau; Anastasia Saade; Nathalie Clément; Thomas Courivaud; Nawel Kaabi; Kenjiro Tadagaki; Philippe Delagrange; Vincent Prévot; Olivier Hermine; Céline Prunier; Ralf Jockers
• Keywords: 0301 basic medicine; [SDV]Life Sciences [q-bio]; Science; Receptor, Transforming Growth Factor-beta Type I; Breast Neoplasms; Mammary Neoplasms, Animal; Nerve Tissue Proteins; Smad Proteins; Endosomes; Article; Receptors, G-Protein-Coupled; Mice; 03 medical and health sciences; Cell Line, Tumor; Animals; Humans; Cell Proliferation; Oligonucleotide Array Sequence Analysis; Gene Expression Profiling; Q; 3. Good health; Mice, Inbred C57BL; HEK293 Cells; Female; Neoplasm Transplantation; HeLa Cells; Signal Transduction

AbstractTransforming growth factor-β (TGFβ) signaling is initiated by the type I, II TGFβ receptor (TβRI/TβRII) complex. Here we report the formation of an alternative complex between TβRI and the orphan GPR50, belonging to the G protein-coupled receptor super-family. The interaction of GPR50 with TβRI induces spontaneous TβRI-dependent Smad and non-Smad signaling by stabilizing the active TβRI conformation and competing for the binding of the negative regulator FKBP12 to TβRI. GPR50 overexpression in MDA-MB-231 cells mimics the anti-proliferative effect of TβRI and decreases tumor growth in a xenograft mouse model. Inversely, targeted deletion of GPR50 in the MMTV/Neu spontaneous mammary cancer model shows decreased survival after tumor onset and increased tumor growth. Low GPR50 expression is associated with poor survival prognosis in human breast cancer irrespective of the breast cancer subtype. This describes a previously unappreciated spontaneous TGFβ-independent activation mode of TβRI and identifies GPR50 as a TβRI co-receptor with potential impact on cancer development.