A role of calcyclin, a Ca(2+)-binding protein, on the Ca(2+)-dependent insulin release from the pancreatic beta cell.
Exocytosis is an important example of cell activation. Ca2+ and calcium-binding proteins are considered to modulate signal transduction in exocytosis. We examined the role of calcyclin, calcium-binding protein, in the stimulus-secretion coupling in pancreatic beta cells. The presence of calcyclin in these cells was demonstrated immunologically. We permeabilized rat pancreatic islets with streptolysin-O and examined the effects of calcyclin on insulin release. The Ca(2+)-stimulated insulin release was enhanced by calcyclin, in a dose-dependent manner, whereas this calcium-binding protein had no effect on insulin release from islets in low Ca2+ buffer or from the islets not subjected to the streptolysin-O treatment. Calgizzarin, another member of the S-100 protein family, had no apparent effect on the Ca(2+)-stimulated secretion under parallel conditions. An anticalcyclin antibody suppressed the increase in insulin release induced by calcyclin. We propose that calcyclin may be involved in signal transduction of the Ca(2+)-induced release of insulin.
Okazaki
K
K
Department of Pharmacology, Nagoya University School of Medicine, Japan.
Niki
I
I
Iino
S
S
Kobayashi
S
S
Hidaka
H
H
D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D001426:Bacterial Proteins; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000502:physiology*; D018797:Cell Cycle Proteins; D007120:Immunochemistry; D007328:Insulin / Q000378:metabolism*; D007515:Islets of Langerhans / Q000378:metabolism*; D008297:Male; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar; D000075383:S100 Calcium Binding Protein A6; D009418:S100 Proteins; D013301:Streptolysins
D000906:Antibodies; D001426:Bacterial Proteins; D002135:Calcium-Binding Proteins; D018797:Cell Cycle Proteins; D007328:Insulin; D000075383:S100 Calcium Binding Protein A6; D009418:S100 Proteins; C489132:S100a6 protein, rat; D013301:Streptolysins; C025964:streptolysin O; D002118:Calcium