The 5-hydroxytryptamine(1A) receptor is stably palmitoylated, and acylation is critical for communication of receptor with Gi protein.
J Biol Chem
; 279(5): 3280-91, 2004 Jan 30.
Article
em En
| MEDLINE
| ID: mdl-14604995
ABSTRACT
In the present study, we verified that the mouse 5-hydroxytryptamine(1A) (5-HT(1A)) receptor is modified by palmitic acid, which is covalently attached to the protein through a thioester-type bond. Palmitoylation efficiency was not modulated by receptor stimulation with agonists. Block of protein synthesis by cycloheximide resulted in a significant reduction of receptor acylation, suggesting that palmitoylation occurs early after synthesis of the 5-HT(1A) receptor. Furthermore, pulse-chase experiments demonstrated that fatty acids are stably attached to the receptor. Two conserved cysteine residues 417 and 420 located in the proximal C-terminal domain were identified as acylation sites by site-directed mutagenesis. To address the functional role of 5-HT(1A) receptor acylation, we have analyzed the ability of acylation-deficient mutants to interact with heterotrimeric G(i) protein and to modulate downstream effectors. Replacement of individual cysteine residues (417 or 420) resulted in a significantly reduced coupling of receptor with G(i) protein and impaired inhibition of adenylyl cyclase activity. When both palmitoylated cysteines were replaced, the communication of receptors with G alpha(i) subunits was completely abolished. Moreover, non-palmitoylated mutants were no longer able to inhibit forskolin-stimulated cAMP formation, indicating that palmitoylation of the 5-HT(1A) receptor is critical for the enabling of G(i) protein coupling/effector signaling. The receptor-dependent activation of extracellular signal-regulated kinase was also affected by acylation-deficient mutants, suggesting the importance of receptor palmitoylation for the signaling through the G beta gamma-mediated pathway, in addition to the G alpha(i)-mediated signaling.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ácidos Palmíticos
/
Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP
/
Receptor 5-HT1A de Serotonina
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
2004
Tipo de documento:
Article