Structural-functional analysis of the third transmembrane domain of the corticotropin-releasing factor type 1 receptor: role in activation and allosteric antagonism.
The corticotropin-releasing factor (CRF) type 1 receptor (CRF1R) for the 41-amino acid peptide CRF is a class B G protein-coupled receptor, which plays a key role in the response of our body to stressful stimuli and the maintenance of homeostasis by regulating neural and endocrine functions. CRF and related peptides, such as sauvagine, bind to the extracellular regions of CRF1R and activate the receptor. In contrast, small nonpeptide antagonists, which are effective against stress-related disorders, such as depression and anxiety, have been proposed to interact with the helical transmembrane domains (TMs) of CRF1R and allosterically antagonize peptide binding and receptor activation. Here, we aimed to elucidate the role of the third TM (TM3) in the molecular mechanisms underlying activation of CRF1R. TM3 was selected because its tilted orientation, relative to the membrane, allows its residues to establish key interactions with ligands, other TM helices, and the G protein. Using a combination of pharmacological, biochemical, and computational approaches, we found that Phe-203(3.40) and Gly-210(3.47) in TM3 play an important role in receptor activation. Our experimental findings also suggest that Phe-203(3.40) interacts with nonpeptide antagonists.
From the Departments of Pharmacology and.
Katerina
K
Spyridaki
the Laboratori de Medicina Computacional, Facultat de Medicina, Universitat Autonoma de Barcelona, Bellaterra 08193, Spain.
Minos-Timotheos
MT
Matsoukas
the Laboratori de Medicina Computacional, Facultat de Medicina, Universitat Autonoma de Barcelona, Bellaterra 08193, Spain.
Arnau
A
Cordomi
From the Departments of Pharmacology and.
Kostas
K
Gkountelias
From the Departments of Pharmacology and.
Maria
M
Papadokostaki
the Laboratory of Organic Chemistry, Department of Chemistry, University of Athens, Athens 11571, Greece, and.
Thomas
T
Mavromoustakos
the Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23298.
Diomedes E
DE
Logothetis
Clinical Chemistry, School of Medicine, University of Crete, Heraklion 71003, Greece.
Andrew N
AN
Margioris
the Laboratori de Medicina Computacional, Facultat de Medicina, Universitat Autonoma de Barcelona, Bellaterra 08193, Spain.
Leonardo
L
Pardo
From the Departments of Pharmacology and liapakis@med.uoc.gr.
George
G
Liapakis
D000494:Allosteric Regulation / Q000187:drug effects; D000595:Amino Acid Sequence; D002462:Cell Membrane / Q000378:metabolism*; D017124:Conserved Sequence; D057809:HEK293 Cells; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017434:Protein Structure, Tertiary; D011743:Pyrimidines / Q000494:pharmacology; D011758:Pyrroles / Q000494:pharmacology; D018019:Receptors, Corticotropin-Releasing Hormone / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D013329:Structure-Activity Relationship; D000099052:CRF Receptor, Type 1
D011743:Pyrimidines; D011758:Pyrroles; D018019:Receptors, Corticotropin-Releasing Hormone; C103016:antalarmin; D000099052:CRF Receptor, Type 1
7-Helix Receptor; Corticotropin-releasing Factor (CRF); G Protein-coupled Receptor (GPCR); Protein Drug Interaction; Protein Structure; Receptor Structure-Function; Type 1 CRF Receptor (CRF1R)