Brefeldin A and a synthetic peptide to ADP-ribosylation factor (ARF) inhibit regulated exocytosis in melanotrophs.
We investigated the role of ADP-ribosylation factor (ARF) in regulated exocytosis in patch-clamped rat melanotrophs. Addition of brefeldin A (BFA) to inhibit activation of endogenous ARF protein was found to attenuate regulated secretory activity monitored as changes in membrane capacitance (Cm). A synthetic peptide to amino acids 46-61 of ARF (P-14) was also found to inhibit Ca(2+)-induced secretory activity in these cells. This inhibition was not apparent with a scrambled amino acid sequence of ARF-P14 peptide. This paper provides the first patch-clamp study to suggest that the small GTP-binding protein ARF is required to trigger release of secretory granules from rat pituitary melanotrophs.
Rupnik
M
M
Laboratory of Neuroendocrinology, School of Medicine, Ljubljana, Slovenia.
Law
G J
GJ
Northrop
A J
AJ
Mason
W T
WT
Zorec
R
R
D020727:ADP-Ribosylation Factors; D000262:Adenylyl Cyclases / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D020126:Brefeldin A; D002118:Calcium / Q000037:antagonists & inhibitors / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D003517:Cyclopentanes / Q000494:pharmacology*; D005089:Exocytosis / Q000187:drug effects*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D018408:Patch-Clamp Techniques; D010903:Pituitary Gland, Anterior / Q000166:cytology* / Q000187:drug effects; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology*; D051381:Rats
D003517:Cyclopentanes; D011500:Protein Synthesis Inhibitors; D020126:Brefeldin A; D019204:GTP-Binding Proteins; D020727:ADP-Ribosylation Factors; D000262:Adenylyl Cyclases; D002118:Calcium