CELL-TYPE SPECIFIC POSTTRANSLATIONAL PROCESSING OF PEPTIDES BY DIFFERENT PITUITARY CELL-LINES
CELL-TYPE SPECIFIC POSTTRANSLATIONAL PROCESSING OF PEPTIDES BY DIFFERENT PITUITARY CELL-LINES
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DOI：
10.1210/endo-127-1-133
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发表时间：
1990-07-01
期刊：
影响因子：
4.8
通讯作者：
MAINS, RE
中科院分区：
文献类型：
--
作者：
DICKERSON, IM;MAINS, RE
为了比较两种不同的垂体细胞类型中的激素原加工，用编码前原神经肽Y（preproNPY）的载体稳定转染生长催乳细胞（GH 3）和促皮质细胞（AtT-20），所述前原神经肽Y（preproNPY）在单个蛋白内切酶裂解位点含有四对不同的碱性氨基酸：野生型或KR（赖氨酸-精氨酸）、RR、RK和KK。GH-NPY细胞系以类似的程度切割proNPY，而不管切割位点处的碱性氨基酸序列如何（KR = RR = RK = KK）。已知AtT-20-NPY细胞在加工野生型和突变的proNPY形式时表现出强烈的切割位点偏好层次（KR = RR > RK > > KK）。所有四种类型的GH-NPY和AtT-NPY细胞忠实地从proNPY（1-69）产生NPY（1-36）NH 2，而不管切割位点的氨基酸序列如何。所有四种类型的GH-NPY细胞都产生一些预期的proNPY-COOH-末端肽，其NH 2-末端具有Ser 40 [proNPY）40-69）]。表达RR、RK和KK形式的proNPY的CH 3细胞另外产生一些保留氨基末端Lys 39或Arg 39残基的proNPY-COOH末端肽。相比之下，ATT-NPY-RK细胞仅产生Lys 39形式的proNPY-COOH-末端肽，而其他三个AtT-NPY系（KR、RR和KK）仅产生Ser 40形式的proNPY-COOH-末端肽。通过用胰岛素、雌二醇和表皮生长因子处理，与PRL合成的预期增加和GH合成的预期减少一致，在GH 3细胞中的proNPY和NPY的停留时间显著增加;在细胞中的停留时间增加并不导致proNPY裂解为NPY的程度增加。AtT-20细胞没有响应的somatomammotrope特定的一套激素。因此，有几个重要的差异，在翻译后加工和储存的肽激素incorticotropes和somatomammotropes。
In order to compare prohormone processing in two distinct pituitary cell types, somatomammotrope cells (GH3) and corticotrope cells (AtT-20) were stably transfected with vectors encoding preproneuropeptide Y (preproNPY) containing four different pairs of basic amino acids at the single endoproteolytic cleavage site: wildtype or KR (lysine-arginine), RR, RK, and KK. The GH-NPY cell lines cleaved proNPY to a similar extent, regardless of the sequence of the basic amino acids at the cleavage site (KR = RR = RK = KK). AtT-20-NPY cells are known to exhibit a strong hierachy of cleavage site preference when processing wildtype and mutated proNPY forms (KR = RR > RK > > KK). All four types of GH-NPY and AtT-NPY cells faithfully produced NPY (1-36) NH2 from proNPY (1-69), regardless of the amino acid sequence at the cleavage site. All four types of GH-NPY cells produced some of the expected proNPY-COOH-terminal peptide with Ser40 at its NH2-terminal [proNPY)40-69)]. CH3 cells expressing the RR, RK, and KK forms of proNPY yielded in addition some proNPY-COOH terminal peptide retaining the amino terminals Lys39 or Arg39 residue. In contrast, ATT-NPY-RK cells produced only the Lys39 form of proNPY-COOH-terminal peptide while the other three AtT-NPY lines (KR, RR, and KK) produced only the Ser40 form of proNPY-COOH-terminal peptide. The residence time of proNPY and NPY in GH3 cells was dramatically increased by treatment with insulin, estradiol, and epidermal growth factor, in concert with the expected increase in PRL synthesis and decrease in GH synthesis; increased residence time in the cells did not result in an increase in the extent of cleavage of proNPY to NPY. AtT-20 cells did not respond to the somatomammotrope-specific set of hormone. Thus, there are several important differences in the posttranslational processing and storage of peptide hormones incorticotropes and somatomammotropes.