Sevarino K A, Felix R, Banks C M, Low M J, Montminy M R, Mandel G, Goodman R H
J Biol Chem. 1987 Apr 15;262(11):4987-93.
We have previously found that preprosomatostatin is processed accurately to both somatostatin-14 and somatostatin-28 in pituitary gonadotrophs of transgenic mice. The foreign somatostatin peptides have been shown to enter the regulated secretory pathway of these cells. To determine whether accurate preprosomatostatin processing can occur in any neuroendocrine cell, we introduced preprosomatostatin cDNA expression vectors into several different neuroendocrine cell lines. We found that prosomatostatin was cleaved efficiently to somatostatin-14 and somatostatin-28 in RIN 5F and AtT20 cells, but not in GH4 or PC12 cells. The ability of a particular cell type to process prosomatostatin did not correlate with cellular storage capacity and was independent of the level of biosynthesis of the precursor. These data suggest that prosomatostatin processing requires specific pathways which are present in some neuroendocrine cells, but not in others.
我们之前发现，在转基因小鼠的垂体促性腺细胞中，前促生长素抑制素能准确加工成生长抑素-14和生长抑素-28。已证实外源生长抑素肽可进入这些细胞的调节性分泌途径。为了确定精确的前促生长素抑制素加工是否能在任何神经内分泌细胞中发生，我们将前促生长素抑制素cDNA表达载体导入几种不同的神经内分泌细胞系。我们发现，在RIN 5F和AtT20细胞中，促生长素抑制素能有效切割成生长抑素-14和生长抑素-28，但在GH4或PC12细胞中则不能。特定细胞类型加工促生长素抑制素的能力与细胞储存能力无关，且独立于前体生物合成水平。这些数据表明，促生长素抑制素加工需要特定途径，这些途径存在于一些神经内分泌细胞中，而不存在于其他细胞中。
