Ca2+ dependency of 'Ca2+-independent' exocytosis in SPOC1 airway goblet cells.
Ca2+ dependency of 'Ca2+-independent' exocytosis in SPOC1 airway goblet cells.
复制标题
SPOC1 气道杯状细胞中“Ca2 独立”胞吐作用的 Ca2 依赖性。
DOI：
10.1113/jphysiol.2004.070433
复制
发表时间：
2004
期刊：
影响因子：
--
通讯作者：
Davis,CWilliam
中科院分区：
文献类型：
--
作者：
Rossi,AndreaH;Sears,PatrickR;Davis,CWilliam
SPOC 1气道杯状细胞分泌粘蛋白，以响应P2 Y2受体激动剂和促分泌素佛波醇12-肉豆蔻酸酯13-乙酸酯（PMA）和离子霉素，它们分别动员磷脂酶C途径的元件、PKC和Ca 2+。先前的研究表明，PMA在低Ca 2+水平（< 0.1 μm）下刺激SLO透化、EGTA缓冲的SPOC 1细胞的粘蛋白分泌，这与调节性胞吐可能通过Ca 2+非依赖性途径发生的观点一致。我们检验了备择假设，即PMA诱导的粘蛋白分泌实际上是低体积Ca 2+条件下的Ca 2+依赖性过程，这在典型的SLO透化细胞模型中是通过EGTA的缓慢结合动力学而允许的。IP 3和升高的散装Ca 2+激活粘液分泌SPOC 1细胞缓冲EGTA，这表明IP 3产生一个局部Ca 2+梯度附近的分泌颗粒的程度，必要的触发胞吐。BAPTA结合Ca 2+的速度比EGTA快约100倍，在一定浓度范围内使IP 3诱导的粘蛋白释放减少≥ 69%，但在透化的SPOC 1细胞中对升高的大量Ca 2+保持基本正常的粘蛋白分泌反应。相对于EGTA缓冲对照，BAPTA还减少了透化细胞对PMA的粘蛋白分泌反应：在低于30 nm的PMA下，BAPTA消除了分泌反应，并且在较高浓度下，其相对于EGTA缓冲对照显著降低。PMA诱导的EGTA分泌对肝素不敏感。这些结果表明，在PMA诱导的胞吐作用期间，Ca 2+通过IP 3非依赖性机制局部释放。
SPOC1 airway goblet cells secrete mucin in response to P2Y2receptor agonists and to secretagogues, phorbol 12‐myristate 13‐acetate (PMA) and ionomycin, which mobilize elements of the phospholipase C pathway, PKC and Ca2+, respectively. Previous studies demonstrated that mucin secretion from SLO‐permeabilized, EGTA‐buffered SPOC1 cells was stimulated by PMA at low Ca2+levels (< 0.1 μm), consistent with the notion that regulated exocytosis may occur by Ca2+‐independent pathways. We tested the alternative hypothesis that PMA‐induced mucin secretion is, in fact, a Ca2+‐dependent process under the conditions of low bulk Ca2+, one that is permitted in the typical SLO‐permeabilized cell model by the slow binding kinetics of EGTA. Both IP3and elevated bulk Ca2+activated mucin secretion in SPOC1 cells buffered by EGTA, suggesting that IP3generates a local Ca2+gradient in the vicinity of the secretory granules to the degree necessary to trigger exocytosis. BAPTA, which binds Ca2+approximately 100‐fold faster than EGTA, diminished IP3‐induced mucin release over a range of concentrations by ≥ 69%, yet maintained an essentially normal mucin secretory response to elevated bulk Ca2+in permeabilized SPOC1 cells. BAPTA also diminished the mucin secretory response of permeabilized cells to PMA, relative to the EGTA‐buffered control: at PMA below 30 nm, BAPTA abolished the secretory response, and at higher concentrations it was reduced significantly relative to the EGTA‐buffered controls. PMA‐induced secretion in EGTA was insensitive to heparin. These results suggest that Ca2+is released locally during PMA‐induced exocytosis, by an IP3‐independent mechanism.
登录
查看更多内容
T 细胞抗原受体同种异型决定簇特异性鼠单克隆抗体的表征。
DOI：
--
发表时间：
1985
期刊：
Journal of immunology (Baltimore, Md. : 1950)
影响因子：
--
作者：
Staerz,UD;Rammensee,HG;Benedetto,JD;Bevan,MJ
通讯作者：
Bevan,MJ
细胞癌基因 (c-Ki-ras) 在小鼠肾上腺皮质肿瘤细胞中被扩增、过度表达并位于核型异常中
影响因子：
64.8
作者：
M. Schwab;K. Alitalo;H. Varmus;J. Bishop;D. George
通讯作者：
D. George
lpr/lpr 小鼠胸腺中的 T 细胞谱系。
影响因子：
4.4
作者：
R. Budd;M. Schreyer;G. Miescher;H. Macdonald
通讯作者：
H. Macdonald
MRL-lpr/lpr 小鼠的淋巴细胞增殖细胞是带有抗原 T 淋巴细胞受体的多克隆细胞群
影响因子：
5.4
作者：
D. Nemazee;Suzanne Studer;M. Steinmetz;Z. Dembić;M. Kiefer
通讯作者：
M. Kiefer
突变基因 Ipr 引起的异常：独特淋巴细胞亚群的扩张。
影响因子：
4.4
作者：
H. Morse;W. Davidson;R. Yetter;E. Murphy;J. Roths;R. Coffman
通讯作者：
R. Coffman