Allosteric Activation of a G Protein-coupled Receptor with Cell-penetrating Receptor Mimetics.
G protein-coupled receptors (GPCRs) are remarkably versatile signaling systems that are activated by a large number of different agonists on the outside of the cell. However, the inside surface of the receptors that couple to G proteins has not yet been effectively modulated for activity or treatment of diseases. Pepducins are cell-penetrating lipopeptides that have enabled chemical and physical access to the intracellular face of GPCRs. The structure of a third intracellular (i3) loop agonist, pepducin, based on protease-activated receptor-1 (PAR1) was solved by NMR and found to closely resemble the i3 loop structure predicted for the intact receptor in the on-state. Mechanistic studies revealed that the pepducin directly interacts with the intracellular H8 helix region of PAR1 and allosterically activates the receptor through the adjacent (D/N)PXXYYY motif through a dimer-like mechanism. The i3 pepducin enhances PAR1/Gα subunit interactions and induces a conformational change in fluorescently labeled PAR1 in a very similar manner to that induced by thrombin. As pepducins can potentially be made to target any GPCR, these data provide insight into the identification of allosteric modulators to this major drug target class.
From the Center of Hemostasis and Thrombosis Research, Molecular Oncology Research Institute, Tufts Medical Center, and Departments of Biochemistry and Medicine, Tufts University School of Medicine, Boston, Massachusetts 02111.
Ping
P
Zhang
From the Center of Hemostasis and Thrombosis Research, Molecular Oncology Research Institute, Tufts Medical Center, and Departments of Biochemistry and Medicine, Tufts University School of Medicine, Boston, Massachusetts 02111.
Andrew J
AJ
Leger
From the Center of Hemostasis and Thrombosis Research, Molecular Oncology Research Institute, Tufts Medical Center, and Departments of Biochemistry and Medicine, Tufts University School of Medicine, Boston, Massachusetts 02111.
James D
JD
Baleja
From the Center of Hemostasis and Thrombosis Research, Molecular Oncology Research Institute, Tufts Medical Center, and Departments of Biochemistry and Medicine, Tufts University School of Medicine, Boston, Massachusetts 02111.
Rajashree
R
Rana
From the Center of Hemostasis and Thrombosis Research, Molecular Oncology Research Institute, Tufts Medical Center, and Departments of Biochemistry and Medicine, Tufts University School of Medicine, Boston, Massachusetts 02111.
Tiffany
T
Corlin
From the Center of Hemostasis and Thrombosis Research, Molecular Oncology Research Institute, Tufts Medical Center, and Departments of Biochemistry and Medicine, Tufts University School of Medicine, Boston, Massachusetts 02111.
Nga
N
Nguyen
From the Center of Hemostasis and Thrombosis Research, Molecular Oncology Research Institute, Tufts Medical Center, and Departments of Biochemistry and Medicine, Tufts University School of Medicine, Boston, Massachusetts 02111.
Georgios
G
Koukos
From the Center of Hemostasis and Thrombosis Research, Molecular Oncology Research Institute, Tufts Medical Center, and Departments of Biochemistry and Medicine, Tufts University School of Medicine, Boston, Massachusetts 02111.
Andrew
A
Bohm
From the Center of Hemostasis and Thrombosis Research, Molecular Oncology Research Institute, Tufts Medical Center, and Departments of Biochemistry and Medicine, Tufts University School of Medicine, Boston, Massachusetts 02111.
Lidija
L
Covic
From the Center of Hemostasis and Thrombosis Research, Molecular Oncology Research Institute, Tufts Medical Center, and Departments of Biochemistry and Medicine, Tufts University School of Medicine, Boston, Massachusetts 02111. Electronic address: athan.kuliopulos@tufts.edu.
Athan
A
Kuliopulos
D000494:Allosteric Regulation / Q000235:genetics; D020816:Amino Acid Motifs; D000818:Animals; D040761:Biomimetic Materials / Q000737:chemistry*; D019556:COS Cells; D057846:Cell-Penetrating Peptides / Q000737:chemistry*; D002522:Chlorocebus aethiops; D044385:GTP-Binding Protein alpha Subunits / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D019906:Nuclear Magnetic Resonance, Biomolecular; D044463:Receptor, PAR-1 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D057846:Cell-Penetrating Peptides; D044385:GTP-Binding Protein alpha Subunits; D044463:Receptor, PAR-1
G protein-coupled receptor (GPCR); biotechnology; cell surface receptor; cell-penetrating peptide (CPP); chemical biology; drug delivery system; nuclear magnetic resonance (NMR); receptor structure-function; signal transduction; thrombin