FEBS Letters | |
A novel Ca2+‐dependent step in exocytosis subsequent to vesicle fusion | |
Lindau, Manfred1  Hartmann, Jana1  | |
[1] Abt. Molekulare Zellforschung, Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, D-69120 Heidelberg, Germany | |
关键词: Exocytosis; Calcium; Eosinophil; Fusion pore; EGTA; ethylene glycol-bis(β-amino-ethyl ether)-N; N; N′; N′-tetraacetic acid; HEDTA; N-hydroxyethylethylenediaminetriacetic acid; GTPγS; guanosine-5′-O-(3-thiotriphosphate); | |
DOI : 10.1016/0014-5793(95)00318-4 | |
学科分类:生物化学/生物物理 | |
来源: John Wiley & Sons Ltd. | |
【 摘 要 】
Exocytosis begins with formation of a small fusion pore which then expands allowing rapid release of granular contents. We studied the influence of cytoplasmic free Ca2+ ([Ca2+]i) on the conductance of the initial pore and on the dynamics of subsequent expansion in horse eosinophils using the patch clamp technique. The mean initial conductance is ∼200 pS independent of [Ca2+]i. This value is close to that previously found in beige mouse mast cells. The pore subsequently expands by 18 nS/s at [Ca2+]i < 10 nM, by 40 nS/s at [Ca2+]i = 1.5 μM and by 90 nS/s at [Ca2+]i = 10 μM. These results show that the structure of the initial fusion pore is independent of cytoplasmic Ca2+. However, the pore expansion is a Ca2+-dependent process modulating secretion at a step later than vesicle-plasma membrane fusion.
【 授权许可】
Unknown
【 预 览 】
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