TY - JOUR
T1 - Properties of plasma membrane-induced amylase release from rat parotid secretory granules
T2 - effects of Ca2+ and Mg-ATP
AU - Mizuno, Masako
AU - Kameyama, Yasunaga
AU - Yashiro, Koji
AU - Ok Shin, Sun
AU - Yokota, Yutaka
N1 - Funding Information:
We are very grateful to Dr. Kouji Yamamoto (Asahi University School of Dentistry, Japan) for the preparation of samples for electron microscopy, and greatly indebted to Professor Yasunobu Okada and Dr. Shigc-loshi Oiki (Kyoto University, Japan) for performing lhc calculations of free calcium concentration. Wc thank Ms. Tcruyo Tanahashi and Dr. Akihiko Okada liar their helpful assistance. This study was supported in part by Grant-in-Aid for Scientific Research from thc Ministry of Education, Science and Culture, Japan and a grant from the Miyata Science Research Foundation of Asahi University, Gifu, Japan.
PY - 1992/4/22
Y1 - 1992/4/22
N2 - A secretory granular fraction (SG) and a plasma membrane rich fraction (PM) have been isolated from rat parotid gland by differential and Percoll gradient centrifugation. With these two fractions, a cell-free interaction system has been reconstituted to clarify the exocytotic between the secretory granules and plasma membranes, and the conditions of amylase release from SG have been characterized in vitro. The addition of PM into this assay system induced a rapid and transient release of amylase from SG. Some other membranes such as erythrocyte ghosts also mimicked the effect of PM. This release was increased by Ca2+, but was not completely blocked by EGTA. Simultaneous addition of 1 mM ATP with 1 mM MgCl2 (Mg-ATP) inthe presence of Ca2+ reduced this release. However, in spite of the existence of Mg-ATP, the stimulation of PM-induced amylase release was caused by Ca2+ in a concentration-dependent manner (10-7-10-3M). These results suggest that Ca2+ and Mg-ATP should participate as important regulators in the exocytotic interaction between secretory granules and plasma membranes in this system. Furthermore, the differences between our system and intact cells are also discussed.
AB - A secretory granular fraction (SG) and a plasma membrane rich fraction (PM) have been isolated from rat parotid gland by differential and Percoll gradient centrifugation. With these two fractions, a cell-free interaction system has been reconstituted to clarify the exocytotic between the secretory granules and plasma membranes, and the conditions of amylase release from SG have been characterized in vitro. The addition of PM into this assay system induced a rapid and transient release of amylase from SG. Some other membranes such as erythrocyte ghosts also mimicked the effect of PM. This release was increased by Ca2+, but was not completely blocked by EGTA. Simultaneous addition of 1 mM ATP with 1 mM MgCl2 (Mg-ATP) inthe presence of Ca2+ reduced this release. However, in spite of the existence of Mg-ATP, the stimulation of PM-induced amylase release was caused by Ca2+ in a concentration-dependent manner (10-7-10-3M). These results suggest that Ca2+ and Mg-ATP should participate as important regulators in the exocytotic interaction between secretory granules and plasma membranes in this system. Furthermore, the differences between our system and intact cells are also discussed.
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U2 - 10.1016/0304-4165(92)90106-5
DO - 10.1016/0304-4165(92)90106-5
M3 - Article
C2 - 1374645
AN - SCOPUS:0026602482
SN - 0304-4165
VL - 1116
SP - 104
EP - 111
JO - BBA - General Subjects
JF - BBA - General Subjects
IS - 2
ER -