A subclass of proteins and sulfated macromolecules secreted by AtT-20 (mouse pituitary tumor) cells is sorted with adrenocorticotropin into dense secretory granules.
A subclass of proteins and sulfated macromolecules secreted by AtT-20 (mouse pituitary tumor) cells is sorted with adrenocorticotropin into dense secretory granules.
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DOI：
10.1083/jcb.97.3.810
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发表时间：
1983-09
期刊：
影响因子：
--
通讯作者：
Kelly RB
中科院分区：
文献类型：
--
作者：
Moore HP;Gumbiner B;Kelly RB
AtT-20细胞是一种分泌促肾上腺皮质激素和β-内啡肽的小鼠垂体瘤细胞系，它将其外化的蛋白质分为两种胞吐途径。用[35 S]甲硫氨酸或[35 S]硫酸盐标记的细胞可以显示出将三种酸性多肽（65，000、60，000和37，000 mol wt）和至少两种硫酸化大分子转运到储存分泌颗粒中。当细胞被促分泌素8-溴-cAMP刺激时，这些多肽与成熟的促肾上腺皮质激素协同分泌到培养基中。相反，一组完全不同的分泌多肽和硫酸化大分子不会进入储存形式，而是更迅速地转运到细胞表面。它们从细胞中分泌是组成性的，不需要促分泌素的存在。这些分子，如先前描述的病毒膜糖蛋白（Gumbiner，B.，和R. B。Kelly，1982，Cell，28：51- 59）在分离的分泌颗粒中没有发现，因此必须在不同的胞吐囊泡中到达细胞表面。尽管存在另一种潜在的分泌途径，但分泌大分子的一个亚类分离到分泌颗粒中，表明这些分子具有与调节激素分泌或储存相关的特定功能。据推测，所有由调节分泌颗粒途径分泌的蛋白质都具有一些共同的性质，使它们靶向分泌颗粒。
The AtT-20 cell, a mouse pituitary tumor line that secretes adrenocorticotropin and beta-endorphin, sorts the proteins it externalizes into two exocytotic pathways. Cells that are labeled with [35S]methionine or [35S]sulfate can be shown to transport three acidic polypeptides (65,000, 60,000, and 37,000 mol wt) and at least two sulfated macromolecules into storage secretory granules. When the cells are stimulated by the secretagogue 8-bromo-cAMP, these polypeptides are coordinately secreted with mature adrenocorticotropin into the culture medium. In contrast, a completely different set of secreted polypeptides and sulfated macromolecules does not enter a storage form and is transported to the cell surface more rapidly. Their secretion from the cells is constitutive and does not require the presence of secretagogues. These molecules, like a viral membrane glycoprotein described previously (Gumbiner, B., and R. B. Kelly, 1982, Cell, 28:51- 59) are not found in isolated secretory granules and therefore must reach the cell surface in a different exocytotic vesicle. The segregation of a subclass of secretory macromolecules into the secretory granules, despite the existence of another potential secretory pathway, suggests that these molecules have specific functions related to regulated hormone secretion or storage. Presumably all of the proteins secreted by the regulated secretory granule pathway share some common property that targets them to the secretory granule.