Rab3D redistribution and function in rat parotid acini.
Rab3D redistribution and function in rat parotid acini.
复制标题
Rab3D 在大鼠腮腺腺泡中的重新分布和功能。
DOI：
10.1002/jcp.10373
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发表时间：
2003
影响因子：
5.6
通讯作者：
Ngyen,Danielle
中科院分区：
文献类型：
--
作者：
Nguyen,Danieele;Jones,Antoinette;Ojakian,GeorgeK;Raffaniello,RobertD;Ngyen,Danielle
这篇文章的勘误表已发表在Journal of Cellular Physiology 199：316，2004。Rab 3D是一种低分子量GTP结合蛋白，据信与许多细胞类型中的调节分泌有关。在腮腺中，Rab 3D定位于分泌颗粒膜或作为与Rab护送蛋白的复合物存在于细胞质中。在本研究中，我们研究了透化腮腺腺泡分泌过程中膜相关Rab 3D的再分布。当透化的腺泡刺激钙和cAMP，淀粉酶释放增加大于基础的两倍。亚细胞组分的定量免疫印迹显示Rab 3D在分泌过程中不与腮腺膜分离。免疫组织化学染色表明Rab 3D与细胞顶极中发现的含淀粉酶颗粒共定位。在用钙和cAMP刺激后，颗粒的Rab 3D和淀粉酶免疫染色似乎更加分散。然而，Rab 3D免疫染色未观察到质膜上，似乎驻留在顶端的细胞质。为了检查Rab 3D在淀粉酶释放中的作用，制备含有myc标记的Rab 3D和Rab 3DQ 81 L（GTP结合突变体）的细胞溶质提取物，并与链球菌溶血素O-透化的腺泡一起孵育。Rab 3D而非Rab 3DQ 81 L与腮腺膜结合，表明Rab 3D与腮腺膜的结合是鸟嘌呤核苷酸依赖性的。此外，野生型和突变Rab 3D抑制激动剂诱导的淀粉酶从透化腮腺腺泡释放。这些观察结果表明，在腮腺腺泡，Rab 3D不解离腮腺膜或重新分配到质膜分泌过程中，并可能发挥抑制作用，调节分泌。野生型Rab 3D和GTP结合突变体都抑制淀粉酶释放的事实表明Rab 3D与膜的结合对于分泌抑制不是必需的。 J.细胞。Physiol. 197：400-408，2003© 2003 Wiley利斯公司
An Erratum has been published for this article in Journal of Cellular Physiology 199: 316, 2004.Rab3D is a low molecular weight GTP‐binding protein believed to be involved with regulated secretion in many cell types. In parotid, Rab3D is localized to secretory granule membranes or present in the cytosol as a complex with Rab escort protein. In the present study, we examined the redistribution of membrane‐associated Rab3D during secretion in permeabilized parotid acini. When permeabilized acini were stimulated with calcium and cAMP, amylase release increased greater than twofold over basal. Quantitative immunoblotting of subcellular fractions revealed that Rab3D did not dissociate from parotid membranes during secretion. Immunohistochemical staining demonstrated that Rab3D co‐localizes with amylase containing granules that are found in the apical pole of the cell. Upon stimulation with calcium and cAMP, Rab3D and amylase immunostaining of granules appeared to be more dispersed. However, Rab3D immunostaining was not observed on the plasma membrane and appeared to reside in the apical cytoplasm. To examine the role of Rab3D in amylase release, cytosolic extracts containing myc‐tagged Rab3D and Rab3DQ81L, a GTP‐binding mutant, were prepared and incubated with streptolysin O‐permeabilized acini. Rab3D, but not Rab3DQ81L, bound to parotid membranes suggesting that Rab3D‐binding to parotid membranes is guanine nucleotide‐dependent. Moreover, wild‐type and mutant Rab3D inhibited agonist‐induced amylase release from permeabilized parotid acini. These observations indicate that in parotid acini, Rab3D does not dissociate from parotid membranes or redistribute to the plasma membrane during secretion, and may play an inhibitory role in regulated secretion. The fact that both wild‐type Rab3D and the GTP‐binding mutant inhibit amylase release suggests that binding of Rab3D to the membrane is not essential for secretory inhibition. J. Cell. Physiol. 197: 400–408, 2003© 2003 Wiley‐Liss, Inc.