PKA-dependent phosphorylation of ribosomal protein S6 does not correlate with translation efficiency in striatonigral and striatopallidal medium-sized spiny neurons

• Published in: The Journal of neuroscience Vol. 35; no. 10; pp. 4113 - 4130
• Main Authors: Biever, Anne, Puighermanal, Emma, Nishi, Akinori, David, Alexandre, Panciatici, Claire, Longueville, Sophie, Xirodimas, Dimitris, Gangarossa, Giuseppe, Meyuhas, Oded, Hervé, Denis, Girault, Jean-Antoine, Valjent, Emmanuel
• Format: Journal Article
• Language: English
• Published: United States Society for Neuroscience 11.03.2015
• Subjects: Animals; Biochemistry, Molecular Biology; Biophysics; Cellular Biology; Corpus Striatum - cytology; Corpus Striatum - drug effects; Cyclic AMP-Dependent Protein Kinases - metabolism; Dopamine and cAMP-Regulated Phosphoprotein 32 - genetics; Dopamine and cAMP-Regulated Phosphoprotein 32 - metabolism; Female; GTP-Binding Protein alpha Subunits - genetics; GTP-Binding Protein alpha Subunits - metabolism; Harringtonines - metabolism; Life Sciences; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Neural Pathways - drug effects; Neural Pathways - physiology; Neurons - drug effects; Neurons - metabolism; Neurons - ultrastructure; Phosphorylation - drug effects; Phosphorylation - genetics; Protein Synthesis Inhibitors - pharmacology; Protein Transport - drug effects; Protein Transport - genetics; Puromycin - pharmacology; Receptors, Dopamine D1 - genetics; Receptors, Dopamine D1 - metabolism; Receptors, Dopamine D2 - genetics; Receptors, Dopamine D2 - metabolism; Ribosomal Protein S6 - metabolism; Signal Transduction - drug effects; Signal Transduction - genetics; Substantia Nigra - cytology; Substantia Nigra - drug effects; Synaptosomes - drug effects; Synaptosomes - metabolism; d-amphetamine; protein synthesis; striatum; ribosomal protein S6; dopamine
• ISSN: 0270-6474; 1529-2401
• DOI: 10.1523/JNEUROSCI.3288-14.2015

Ribosomal protein S6 (rpS6), a component of the 40S ribosomal subunit, is phosphorylated on several residues in response to numerous stimuli. Although commonly used as a marker for neuronal activity, its upstream mechanisms of regulation are poorly studied and its role in protein synthesis remains largely debated. Here, we demonstrate that the psychostimulant d-amphetamine (d-amph) markedly increases rpS6 phosphorylation at Ser235/236 sites in both crude and synaptoneurosomal preparations of the mouse striatum. This effect occurs selectively in D1R-expressing medium-sized spiny neurons (MSNs) and requires the cAMP/PKA/DARPP-32/PP-1 cascade, whereas it is independent of mTORC1/p70S6K, PKC, and ERK signaling. By developing a novel assay to label nascent peptidic chains, we show that the rpS6 phosphorylation induced in striatonigral MSNs by d-amph, as well as in striatopallidal MSNs by the antipsychotic haloperidol or in both subtypes by papaverine, is not correlated with the translation of global or 5' terminal oligopyrimidine tract mRNAs. Together, these results provide novel mechanistic insights into the in vivo regulation of the post-translational modification of rpS6 in the striatum and point out the lack of a relationship between PKA-dependent rpS6 phosphorylation and translation efficiency.