Phorbol esters promote postsynaptic accumulation of Vesl-1S/Homer-1a protein.
We examined effects of phorbol esters on the amount and the subcellular distribution of the activity-regulated protein Vesl-1S/Homer-1a in cultured hippocampal neurons. Major Vesl-1S immunoreactivity (IR) was detected throughout neuronal somata under control conditions. Bath application of phorbol esters, PMA and PDBu resulted in the increase in the amount of Vesl-1S proteins and promoted punctate distribution of Vesl-1S IR at the cortical regions of the neuronal somata. Immunofluorescent observations using antisynaptophysin and anti-Vesl-1S antibodies, and electron microscopic observations, revealed that Vesl-1S accumulated at postsynaptic regions following PMA application. Membrane depolarization with high concentrations of external potassium also promoted the punctate distribution of Vesl-1S IR. These results demonstrate that phorbol-triggered reaction cascades result in the accumulation of Vesl-1S protein at postsynaptic regions, and suggest that these phorbol effects may mimic those caused by synaptic activities.
Kato
A
A
Department of Biology, Graduate School of Science, Kyushu University, Higashi-ku, Fukuoka 812-8581, Japan. akatoscb@mbox.nc.kyushu-u.ac.jp
Fukuda
T
T
Fukazawa
Y
Y
Isojima
Y
Y
Fujitani
K
K
Inokuchi
K
K
Sugiyama
H
H
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D017398:Alternative Splicing; D000818:Animals; D000841:Anisomycin / Q000494:pharmacology; D002273:Carcinogens / Q000494:pharmacology*; D002352:Carrier Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D006624:Hippocampus / Q000166:cytology; D000072233:Homer Scaffolding Proteins; D016253:Microscopy, Immunoelectron; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009479:Neuropeptides / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology*; D011188:Potassium / Q000494:pharmacology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013570:Synaptic Membranes / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D013779:Tetrodotoxin / Q000494:pharmacology
D002273:Carcinogens; D002352:Carrier Proteins; D018691:Excitatory Amino Acid Antagonists; D000072233:Homer Scaffolding Proteins; D009479:Neuropeptides; D011500:Protein Synthesis Inhibitors; D015240:Phorbol 12,13-Dibutyrate; D013779:Tetrodotoxin; D000841:Anisomycin; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D013755:Tetradecanoylphorbol Acetate; D011188:Potassium