The dual G protein-coupled receptor 17 (GPR17) is required for the initial differentiation of oligodendrocyte precursor cells (OPCs) but has to be down-regulated to allow OPCs to enter the terminal phases of maturation. We have demonstrated that, upon agonist stimulation, GPR17 undergoes clathrin-dependent endocytosis followed by endosomal sorting to lysosomal degradation or plasma membrane recycling. The fine regulation of this sorting may influence the cells’ ability to undergo terminal differentiation by regulating the levels of cell surface receptors. In order to investigate the mechanisms underlying GPR17 sorting, we analysed the role of the PDZ-binding motif at the C-terminal of the receptor using a combination of biochemical and cellular biological methods, and found that this site regulates receptor recycling after endocytosis because its disruption (obtained by means of site-directed mutagenesis) increases intracellular GPR17 levels. Furthermore, analysis of different candidates in pull-down experiments showed that SNX27 interacts with GPR17-C-terminal. SNX27 is emerging as a regulator of recycling of various receptors from early endosomes to the plasma membrane via interaction with the retromer complexes. Our preliminary immunofluorescence data after in vivo labelling indicate that GPR17 and SNX27 co-localise at the level of the endosomal compartments. Moreover, SNX27 silencing decreases GPR17 levels in a similar manner to that which would occur in the case of defective recycling and increased lysosomal degradation. These findings suggest that the PDZ binding motif is required for plasma membrane recycling of GPR17 via SNX27-retromer complexes.
A PDZ binding motif controls G protein-coupled receptor 17 trafficking in differentiating oligodendrocytes / V. Meraviglia, A.F. Ulivi, A. Fratangeli, F. Valenza, D. Lecca, L. Sironi, M.P. Abbracchio, P. Rosa. ((Intervento presentato al 9. convegno FENS tenutosi a Milano nel 2014.
A PDZ binding motif controls G protein-coupled receptor 17 trafficking in differentiating oligodendrocytes
A.F. UliviSecondo
;A. Fratangeli;D. Lecca;L. Sironi;M.P. AbbracchioPenultimo
;
2014
Abstract
The dual G protein-coupled receptor 17 (GPR17) is required for the initial differentiation of oligodendrocyte precursor cells (OPCs) but has to be down-regulated to allow OPCs to enter the terminal phases of maturation. We have demonstrated that, upon agonist stimulation, GPR17 undergoes clathrin-dependent endocytosis followed by endosomal sorting to lysosomal degradation or plasma membrane recycling. The fine regulation of this sorting may influence the cells’ ability to undergo terminal differentiation by regulating the levels of cell surface receptors. In order to investigate the mechanisms underlying GPR17 sorting, we analysed the role of the PDZ-binding motif at the C-terminal of the receptor using a combination of biochemical and cellular biological methods, and found that this site regulates receptor recycling after endocytosis because its disruption (obtained by means of site-directed mutagenesis) increases intracellular GPR17 levels. Furthermore, analysis of different candidates in pull-down experiments showed that SNX27 interacts with GPR17-C-terminal. SNX27 is emerging as a regulator of recycling of various receptors from early endosomes to the plasma membrane via interaction with the retromer complexes. Our preliminary immunofluorescence data after in vivo labelling indicate that GPR17 and SNX27 co-localise at the level of the endosomal compartments. Moreover, SNX27 silencing decreases GPR17 levels in a similar manner to that which would occur in the case of defective recycling and increased lysosomal degradation. These findings suggest that the PDZ binding motif is required for plasma membrane recycling of GPR17 via SNX27-retromer complexes.Pubblicazioni consigliate
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