Regulation by phorbol esters of the glycine transporter (GLYT1) in glioblastoma cells.
The high-affinity glycine transporter in neurons and glial cells is the primary means of inactivating synaptic glycine. The effects of 12-O-tetradecanoylphorbol ester (TPA), a potent activator of protein kinase C (PKC), on the high-affinity Na(+)-dependent glycine transport were investigated in C6 cells, a cell line of glial origin. Incubation of C6 cells with TPA led to concentration- and time-dependent decrease in the glycine transport that could be completely suppressed by the addition of the PKC inhibitor staurosporine. The TPA effect could be mimicked by oleoylacetylglycerol and exogenous phospholipase C. Northern and Western blot analysis indicate that C6 cells express the GLYT1 glycine transporter. Incubation of COS cells transiently transfected with a full-length clone of the GLYT1 transporter in the presence of TPA, produces a decrease in glycine uptake.
Centro de Biología Molecular Severo Ochoa, Facultad de Ciencias, Universidad Autónoma de Madrid, C.S.I.C., Spain.
J
J
Gomeza
F
F
Zafra
L
L
Olivares
C
C
Giménez
C
C
Aragón
D000470:Alkaloids / Q000494:pharmacology; D026921:Amino Acid Transport Systems, Neutral; D000818:Animals; D001483:Base Sequence; D001692:Biological Transport / Q000187:drug effects; D002352:Carrier Proteins / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D005909:Glioblastoma; D005998:Glycine / Q000378:metabolism*; D050487:Glycine Plasma Membrane Transport Proteins; D008969:Molecular Sequence Data; D009457:Neuroglia / Q000187:drug effects* / Q000378:metabolism; D016376:Oligonucleotides, Antisense; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats; D011994:Recombinant Proteins; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D000470:Alkaloids; D026921:Amino Acid Transport Systems, Neutral; D002352:Carrier Proteins; D050487:Glycine Plasma Membrane Transport Proteins; D016376:Oligonucleotides, Antisense; D011994:Recombinant Proteins; C493266:Slc6a9 protein, rat; D011493:Protein Kinase C; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate; D005998:Glycine