Peptide inhibitors disrupt the serotonin 5-HT2C receptor interaction with phosphatase and tensin homolog to allosterically modulate cellular signaling and behavior.
Serotonin (5-hydroxytryptamine; 5-HT) signaling through the 5-HT(2C) receptor (5-HT(2C)R) is essential in normal physiology, whereas aberrant 5-HT(2C)R function is thought to contribute to the pathogenesis of multiple neural disorders. The 5-HT(2C)R interacts with specific protein partners, but the impact of such interactions on 5-HT(2C)R function is poorly understood. Here, we report convergent cellular and behavioral data that the interaction between the 5-HT(2C)R and protein phosphatase and tensin homolog (PTEN) serves as a regulatory mechanism to control 5-HT(2C)R-mediated biology but not that of the closely homologous 5-HT(2A)R. A peptide derived from the third intracellular loop of the human 5-HT(2C)R [3L4F (third loop, fourth fragment)] disrupted the association, allosterically augmented 5-HT(2C)R-mediated signaling in live cells, and acted as a positive allosteric modulator in rats in vivo. We identified the critical residues within an 8 aa fragment of the 3L4F peptide that maintained efficacy (within the picomolar range) in live cells similar to that of the 3L4F peptide. Last, molecular modeling identified key structural features and potential interaction sites of the active 3L4F peptides against PTEN. These compelling data demonstrate the specificity and importance of this protein assembly in cellular events and behaviors mediated by 5-HT(2C)R signaling and provide a chemical guidepost to the future development of drug-like peptide or small-molecule inhibitors as neuroprobes to study 5-HT(2C)R allostery and therapeutics for 5-HT(2C)R-mediated disorders.
Center for Addiction Research, University of Texas Medical Branch, Galveston, Texas 77555, USA.
Noelle C
NC
Anastasio
Scott R
SR
Gilbertson
Marcy J
MJ
Bubar
Anton
A
Agarkov
Sonja J
SJ
Stutz
Yowjiun
Y
Jeng
Nicole M
NM
Bremer
Thressa D
TD
Smith
Robert G
RG
Fox
Sarah E
SE
Swinford
Patricia K
PK
Seitz
Marc N
MN
Charendoff
John W
JW
Craft
Fernanda M
FM
Laezza
Cheryl S
CS
Watson
James M
JM
Briggs
Kathryn A
KA
Cunningham
D000595:Amino Acid Sequence; D000818:Animals; D006801:Humans; D015151:Immunoblotting; D047468:Immunoprecipitation; D008297:Male; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009043:Motor Activity / Q000502:physiology; D051059:PTEN Phosphohydrolase / Q000737:chemistry* / Q000378:metabolism*; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D044405:Receptor, Serotonin, 5-HT2C / Q000737:chemistry* / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D014162:Transfection
D010446:Peptide Fragments; D044405:Receptor, Serotonin, 5-HT2C; D012701:Serotonin; D051059:PTEN Phosphohydrolase