Botulinum neurotoxin F, a VAMP-specific endopeptidase, inhibits Ca(2+)-stimulated GH secretion from rat pituitary cells.
Botulinum neurotoxin F (BoNTx F) is a zinc-dependent endopeptidase that causes proteolytic cleavage of the vesicle protein VAMP (vesicle-associated membrane protein). VAMP is an important component of the molecular machinery regulating docking and fusion of secretory vesicles with the target membrane. We have investigated presence of VAMP protein in cultured rat anterior pituitary cells. Confocal laser microscopy revealed presence of VAMP-like immunoreactivity in secretory granules of GH-containing cultured rat anterior pituitary cells. Using BoNTx F, we have investigated whether VAMP is involved in growth hormone (GH) secretion. Treatment of streptolysin-O permeabilized GH-secreting cells with BoNTx F (2.0 and 20 nM) significantly inhibited Ca(2+)-induced GH release. The results show that the secretory granules of rat anterior pituitary cell contain VAMP protein and suggest that VAMP is of importance in regulating Ca(2+)-mediated GH secretion.
Jacobsson
G
G
Department of Neuroscience, karolinska Institute, Stockholm, Sweden.
Håkansson
M L
ML
Hulting
A L
AL
Meister
B
B
D000818:Animals; D001426:Bacterial Proteins; D001905:Botulinum Toxins / Q000633:toxicity*; D002118:Calcium / Q000494:pharmacology*; D002463:Cell Membrane Permeability / Q000187:drug effects; D002478:Cells, Cultured; D013006:Growth Hormone / Q000378:metabolism*; D007150:Immunohistochemistry; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000187:drug effects / Q000502:physiology; D018613:Microscopy, Confocal; D009419:Nerve Tissue Proteins / Q000096:biosynthesis* / Q000187:drug effects / Q000502:physiology; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D050683:R-SNARE Proteins; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D013301:Streptolysins / Q000378:metabolism
D001426:Bacterial Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D050683:R-SNARE Proteins; D013301:Streptolysins; C025964:streptolysin O; D013006:Growth Hormone; D001905:Botulinum Toxins; D002118:Calcium; C096321:botulinum toxin type F